Merge branch 'master' into fastlanefastlane

# Conflicts:
#	fastlane/metadata/android/en-US/images/phoneScreenshots/1.png
#	fastlane/metadata/android/en-US/images/phoneScreenshots/2.png
#	fastlane/metadata/android/en-US/images/phoneScreenshots/4.png

222 files changed, 9426 insertions, 2898 deletions

diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/DeckApplication.java b/app/src/main/java/it/niedermann/nextcloud/deck/DeckApplication.java
index ff492c226..cf30a0971 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/DeckApplication.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/DeckApplication.java
@@ -1,20 +1,17 @@
 package it.niedermann.nextcloud.deck;
 
-import android.app.Application;
 import android.content.Context;
 import android.content.SharedPreferences;
 
 import androidx.annotation.NonNull;
+import androidx.multidex.MultiDexApplication;
 import androidx.preference.PreferenceManager;
 
-import com.jakewharton.threetenabp.AndroidThreeTen;
-
 import static androidx.appcompat.app.AppCompatDelegate.MODE_NIGHT_NO;
 import static androidx.appcompat.app.AppCompatDelegate.MODE_NIGHT_YES;
 import static androidx.appcompat.app.AppCompatDelegate.setDefaultNightMode;
-import static androidx.multidex.MultiDex.install;
 
-public class DeckApplication extends Application {
+public class DeckApplication extends MultiDexApplication {
 
     public static final long NO_ACCOUNT_ID = -1L;
     public static final long NO_BOARD_ID = -1L;
@@ -24,17 +21,6 @@ public class DeckApplication extends Application {
     public void onCreate() {
         setAppTheme(isDarkTheme(getApplicationContext()));
         super.onCreate();
-        AndroidThreeTen.init(this);
-    }
-
-    // --------
-    // Multidex
-    // --------
-
-    @Override
-    protected void attachBaseContext(Context base) {
-        super.attachBaseContext(base);
-        install(this);
     }
 
     // -----------------
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/DeckAPI.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/DeckAPI.java
index 9883608c2..1f0148b91 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/DeckAPI.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/DeckAPI.java
@@ -1,6 +1,8 @@
 package it.niedermann.nextcloud.deck.api;
 
 
+import com.nextcloud.android.sso.api.ParsedResponse;
+
 import java.util.List;
 
 import io.reactivex.Observable;
@@ -33,6 +35,7 @@ import retrofit2.http.Query;
 public interface DeckAPI {
 
     String MODIFIED_SINCE_HEADER = "If-Modified-Since";
+    String IF_NONE_MATCH = "If-None-Match";
 
     // ### BOARDS
     @POST("boards")
@@ -51,7 +54,7 @@ public interface DeckAPI {
     Observable<FullBoard> restoreBoard(@Path("id") long id);
 
     @GET("boards")
-    Observable<List<FullBoard>> getBoards(@Query ("details") boolean verbose, @Header(MODIFIED_SINCE_HEADER) String lastSync );
+    Observable<ParsedResponse<List<FullBoard>>> getBoards(@Query ("details") boolean verbose, @Header(MODIFIED_SINCE_HEADER) String lastSync, @Header(IF_NONE_MATCH) String eTag);
 
 
     // ### Stacks
@@ -83,11 +86,11 @@ public interface DeckAPI {
 
     @FormUrlEncoded
     @PUT("boards/{boardId}/stacks/{stackId}/cards/{cardId}/assignLabel")
-    Observable assignLabelToCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Field("labelId") long labelId);
+    Observable<Void> assignLabelToCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Field("labelId") long labelId);
 
     @FormUrlEncoded
     @PUT("boards/{boardId}/stacks/{stackId}/cards/{cardId}/removeLabel")
-    Observable unassignLabelFromCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Field("labelId") long labelId);
+    Observable<Void> unassignLabelFromCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Field("labelId") long labelId);
 
     @FormUrlEncoded
     @PUT("boards/{boardId}/stacks/{stackId}/cards/{cardId}/assignUser")
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonConfig.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonConfig.java
index 29b3706fa..4e61abfb3 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonConfig.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonConfig.java
@@ -5,7 +5,7 @@ import com.google.gson.GsonBuilder;
 import com.google.gson.reflect.TypeToken;
 
 import java.lang.reflect.Type;
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.model.Attachment;
@@ -16,6 +16,8 @@ import it.niedermann.nextcloud.deck.model.full.FullStack;
 import it.niedermann.nextcloud.deck.model.ocs.Activity;
 import it.niedermann.nextcloud.deck.model.ocs.Capabilities;
 import it.niedermann.nextcloud.deck.model.ocs.comment.OcsComment;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectList;
+import it.niedermann.nextcloud.deck.model.ocs.user.GroupMemberUIDs;
 import it.niedermann.nextcloud.deck.model.ocs.user.OcsUser;
 import it.niedermann.nextcloud.deck.model.ocs.user.OcsUserList;
 
@@ -42,14 +44,17 @@ public class GsonConfig {
         Type ocsUserList = new TypeToken<OcsUserList>() {}.getType();
         Type ocsUser = new TypeToken<OcsUser>() {}.getType();
         Type activity = new TypeToken<Activity>() {}.getType();
+        Type activityList = new TypeToken<List<Activity>>() {}.getType();
         Type attachment = new TypeToken<Attachment>() {}.getType();
         Type attachmentList = new TypeToken<List<Attachment>>() {}.getType();
         Type comment = new TypeToken<OcsComment>() {}.getType();
+        Type projectList = new TypeToken<OcsProjectList>() {}.getType();
+        Type groupMembers = new TypeToken<GroupMemberUIDs>() {}.getType();
 
         INSTANCE = new GsonBuilder()
                 .setDateFormat(DATE_PATTERN)
                 .setLenient()
-                .registerTypeAdapter(Date.class,        new GsonUTCDateAdapter())
+                .registerTypeAdapter(Instant.class,     new GsonUTCInstantAdapter())
                 .registerTypeAdapter(boardList,         new NextcloudArrayDeserializer<>("boards", FullBoard.class))
                 .registerTypeAdapter(board,             new NextcloudDeserializer<>("board", FullBoard.class))
                 .registerTypeAdapter(cardList,          new NextcloudArrayDeserializer<>("cards", FullCard.class))
@@ -62,9 +67,12 @@ public class GsonConfig {
                 .registerTypeAdapter(ocsUserList,       new NextcloudDeserializer<>("ocsUserList", OcsUserList.class))
                 .registerTypeAdapter(ocsUser,           new NextcloudDeserializer<>("ocsUser", OcsUser.class))
                 .registerTypeAdapter(activity,          new NextcloudDeserializer<>("activity", Activity.class))
+                .registerTypeAdapter(activityList,      new NextcloudDeserializer<>("activityList", Activity.class))
                 .registerTypeAdapter(attachmentList,    new NextcloudArrayDeserializer<>("attachments", Attachment.class))
                 .registerTypeAdapter(attachment,        new NextcloudDeserializer<>("attachment", Attachment.class))
                 .registerTypeAdapter(comment,           new NextcloudDeserializer<>("comment", OcsComment.class))
+                .registerTypeAdapter(projectList,       new NextcloudDeserializer<>("projectList", OcsProjectList.class))
+                .registerTypeAdapter(groupMembers,      new NextcloudDeserializer<>("groupMembers", GroupMemberUIDs.class))
                 .create();
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonUTCDateAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonUTCDateAdapter.java
deleted file mode 100644
index 4d30b3e81..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonUTCDateAdapter.java
+++ /dev/null
@@ -1,48 +0,0 @@
-package it.niedermann.nextcloud.deck.api;
-
-import com.google.gson.JsonDeserializationContext;
-import com.google.gson.JsonDeserializer;
-import com.google.gson.JsonElement;
-import com.google.gson.JsonParseException;
-import com.google.gson.JsonPrimitive;
-import com.google.gson.JsonSerializationContext;
-import com.google.gson.JsonSerializer;
-
-import java.lang.reflect.Type;
-import java.text.DateFormat;
-import java.text.ParseException;
-import java.text.SimpleDateFormat;
-import java.util.Date;
-import java.util.Locale;
-import java.util.TimeZone;
-import java.util.regex.Pattern;
-
-public class GsonUTCDateAdapter implements JsonSerializer<Date>, JsonDeserializer<Date> {
-
-    private final DateFormat dateFormat;
-    private final Pattern UNIX_TIMESTAMP = Pattern.compile("^[0-9]+$");
-
-    public GsonUTCDateAdapter() {
-        //This is the format I need
-      dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.US);
-      //This is the key line which converts the date to UTC which cannot be accessed with the default serializer
-      dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
-    }
-
-    @Override public synchronized JsonElement serialize(Date date, Type type, JsonSerializationContext jsonSerializationContext) {
-        return new JsonPrimitive(dateFormat.format(date));
-    }
-
-    @Override public synchronized Date deserialize(JsonElement jsonElement, Type type, JsonDeserializationContext jsonDeserializationContext) {
-        String dateValue = jsonElement.getAsString();
-        try {
-          return dateFormat.parse(dateValue);
-      } catch (ParseException e) {
-          // fallback to unix timestamp?
-          if (UNIX_TIMESTAMP.matcher(dateValue).matches()){
-              return new Date(Long.valueOf(dateValue));
-          }
-          throw new JsonParseException(e);
-      }
-    }
-}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonUTCInstantAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonUTCInstantAdapter.java
new file mode 100644
index 000000000..5a6b5b0c0
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/GsonUTCInstantAdapter.java
@@ -0,0 +1,43 @@
+package it.niedermann.nextcloud.deck.api;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+
+import java.lang.reflect.Type;
+import java.text.ParseException;
+import java.time.Instant;
+import java.time.format.DateTimeFormatter;
+import java.util.regex.Pattern;
+
+public class GsonUTCInstantAdapter implements JsonSerializer<Instant>, JsonDeserializer<Instant> {
+
+    private static final Pattern UNIX_TIMESTAMP = Pattern.compile("^[0-9]+$");
+
+    @Override
+    public synchronized JsonElement serialize(Instant date, Type type, JsonSerializationContext jsonSerializationContext) {
+        return new JsonPrimitive(DateTimeFormatter.ISO_INSTANT.format(date));
+    }
+
+    @Override
+    public synchronized Instant deserialize(JsonElement jsonElement, Type type, JsonDeserializationContext jsonDeserializationContext) {
+        String dateValue = jsonElement.getAsString();
+        try {
+            final Instant parsedDate = Instant.parse(dateValue);
+            if (parsedDate == null) {
+                throw new ParseException("Parsed date is null", 0);
+            }
+            return parsedDate;
+        } catch (ParseException e) {
+            // fallback to unix timestamp?
+            if (UNIX_TIMESTAMP.matcher(dateValue).matches()) {
+                return Instant.ofEpochMilli(Long.parseLong(dateValue));
+            }
+            throw new JsonParseException(e);
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/IResponseCallback.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/IResponseCallback.java
index 0e523c318..be3eaeb22 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/IResponseCallback.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/IResponseCallback.java
@@ -24,12 +24,18 @@ public abstract class IResponseCallback<T> {
         DeckLog.logError(throwable);
     }
 
+    @CallSuper
+    public void onError(Throwable throwable, T locallyCreatedEntity) {
+        onError(throwable);
+    }
+
     public static <T> IResponseCallback<T> getDefaultResponseCallback(Account account) {
         return new IResponseCallback<T>(account) {
             @Override
             public void onResponse(T response) {
                 // Do Nothing
             }
+
         };
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/JsonToEntityParser.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/JsonToEntityParser.java
index 6dedefa01..e759f27d4 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/JsonToEntityParser.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/JsonToEntityParser.java
@@ -1,20 +1,20 @@
 package it.niedermann.nextcloud.deck.api;
 
+import android.graphics.Color;
+
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 
-import org.threeten.bp.DateTimeUtils;
-import org.threeten.bp.ZonedDateTime;
-import org.threeten.bp.format.DateTimeFormatter;
-
+import java.time.Instant;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.List;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.exceptions.DeckException;
-import it.niedermann.nextcloud.deck.exceptions.TraceableException;
 import it.niedermann.nextcloud.deck.model.AccessControl;
 import it.niedermann.nextcloud.deck.model.Attachment;
 import it.niedermann.nextcloud.deck.model.Board;
@@ -32,13 +32,19 @@ import it.niedermann.nextcloud.deck.model.ocs.Version;
 import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.Mention;
 import it.niedermann.nextcloud.deck.model.ocs.comment.OcsComment;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectList;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.model.ocs.user.GroupMemberUIDs;
 import it.niedermann.nextcloud.deck.model.ocs.user.OcsUser;
 import it.niedermann.nextcloud.deck.model.ocs.user.OcsUserList;
 
 import static it.niedermann.nextcloud.deck.exceptions.DeckException.Hint.CAPABILITIES_VERSION_NOT_PARSABLE;
+import static it.niedermann.nextcloud.deck.exceptions.TraceableException.makeTraceableIfFails;
 
 public class JsonToEntityParser {
 
+    @SuppressWarnings("unchecked")
     protected static <T> T parseJsonObject(JsonObject obj, Class<T> mType) {
         if (mType == FullBoard.class) {
             return (T) parseBoard(obj);
@@ -55,44 +61,54 @@ public class JsonToEntityParser {
         } else if (mType == OcsUserList.class) {
             return (T) parseOcsUserList(obj);
         } else if (mType == OcsUser.class) {
-            return (T) parseOcsUser(obj);
+            return (T) parseSingleOcsUser(obj);
         } else if (mType == Attachment.class) {
             return (T) parseAttachment(obj);
         } else if (mType == OcsComment.class) {
             return (T) parseOcsComment(obj);
+        } else if (mType == GroupMemberUIDs.class) {
+            return (T) parseGroupMemberUIDs(obj);
+        } else if (mType == OcsProjectList.class) {
+            return (T) parseOcsProjectList(obj);
         }
         throw new IllegalArgumentException("unregistered type: " + mType.getCanonicalName());
     }
 
-    private static OcsUser parseOcsUser(JsonObject obj) {
+    private static GroupMemberUIDs parseGroupMemberUIDs(JsonObject obj) {
         DeckLog.verbose(obj.toString());
-        OcsUser ocsUser = new OcsUser();
-        TraceableException.makeTraceableIfFails(() -> {
+        GroupMemberUIDs uids = new GroupMemberUIDs();
+        makeTraceableIfFails(() -> {
             JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
-            if (!data.isJsonNull()) {
-                JsonObject jsonObject = data.getAsJsonObject();
-                if (jsonObject.has("id")) {
-                    ocsUser.setId(getNullAsEmptyString(jsonObject.get("id")));
-                }
-                if (jsonObject.has("displayname")) {
-                    ocsUser.setDisplayName(getNullAsEmptyString(jsonObject.get("displayname")));
+            if (!data.isJsonNull() && data.getAsJsonObject().has("users")) {
+                JsonElement users = data.getAsJsonObject().get("users");
+                if (!users.isJsonNull() && users.isJsonArray()) {
+                    for (JsonElement userElement : users.getAsJsonArray()) {
+                        uids.add(userElement.getAsString());
+                    }
                 }
             }
 
         }, obj);
-        return ocsUser;
+        return uids;
     }
 
     private static OcsUserList parseOcsUserList(JsonObject obj) {
         DeckLog.verbose(obj.toString());
         OcsUserList ocsUserList = new OcsUserList();
-        TraceableException.makeTraceableIfFails(() -> {
+        makeTraceableIfFails(() -> {
             JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
             if (!data.isJsonNull() && data.getAsJsonObject().has("users")) {
                 JsonElement users = data.getAsJsonObject().get("users");
                 if (!users.isJsonNull() && users.isJsonArray()) {
                     for (JsonElement userElement : users.getAsJsonArray()) {
-                        ocsUserList.add(userElement.getAsString());
+                        JsonObject singleUserElement = userElement.getAsJsonObject();
+                        OcsUser user = new OcsUser();
+                        user.setDisplayName(singleUserElement.get("label").getAsString());
+                        user.setId(
+                                singleUserElement.get("value").getAsJsonObject()
+                                        .get("shareWith").getAsString()
+                        );
+                        ocsUserList.addUser(user);
                     }
                 }
             }
@@ -101,10 +117,105 @@ public class JsonToEntityParser {
         return ocsUserList;
     }
 
+    private static OcsUser parseSingleOcsUser(JsonObject obj) {
+        DeckLog.verbose(obj.toString());
+        OcsUser ocsUser = new OcsUser();
+        makeTraceableIfFails(() -> {
+            JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
+            if (!data.isJsonNull()) {
+                JsonObject user = data.getAsJsonObject();
+                if (user.has("id")) {
+                    ocsUser.setId(user.get("id").getAsString());
+                }
+                if (user.has("displayname")) {
+                    ocsUser.setDisplayName(user.get("displayname").getAsString());
+                }
+            }
+
+        }, obj);
+        return ocsUser;
+    }
+
+    private static OcsProjectList parseOcsProjectList(JsonObject obj) {
+        DeckLog.verbose(obj.toString());
+        OcsProjectList projectList = new OcsProjectList();
+        makeTraceableIfFails(() -> {
+            JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
+            if (!data.isJsonNull() && data.isJsonArray()) {
+                JsonArray projectJsonArray = data.getAsJsonArray();
+                for (JsonElement jsonArrayElement : projectJsonArray) {
+                    if (jsonArrayElement.isJsonObject()) {
+                        JsonObject jsonObject = jsonArrayElement.getAsJsonObject();
+                        OcsProject project = new OcsProject();
+                        project.setId(jsonObject.get("id").getAsLong());
+                        project.setName(getNullAsEmptyString(jsonObject.get("name")));
+                        project.setResources(new ArrayList<>());
+                        JsonElement jsonResources = jsonObject.get("resources");
+                        if (jsonResources != null && jsonResources.isJsonArray()) {
+                            JsonArray resourcesArray = jsonResources.getAsJsonArray();
+                            for (JsonElement resourceElement : resourcesArray) {
+                                if (resourceElement.isJsonObject()) {
+                                    OcsProjectResource resource = parseOcsProjectResource(resourceElement.getAsJsonObject());
+                                    resource.setProjectId(project.getId());
+                                    project.getResources().add(resource);
+                                }
+                            }
+                        }
+                        projectList.add(project);
+                    }
+                }
+            }
+
+        }, obj);
+        return projectList;
+    }
+
+    private static OcsProjectResource parseOcsProjectResource(JsonObject obj) {
+        DeckLog.verbose(obj.toString());
+        OcsProjectResource resource = new OcsProjectResource();
+        makeTraceableIfFails(() -> {
+            if (obj.has("id")) {
+                String idString = obj.get("id").getAsString();
+                if (idString != null && idString.trim().length() > 0) {
+                    if (idString.matches("[0-9]+")) {
+                        resource.setId(Long.parseLong(idString.trim()));
+                    } else {
+                        resource.setIdString(idString);
+                    }
+                }
+            }
+            if (obj.has("type")) {
+                resource.setType(getNullAsEmptyString(obj.get("type")));
+            }
+            if (obj.has("name")) {
+                resource.setName(getNullAsEmptyString(obj.get("name")));
+            }
+            if (obj.has("link")) {
+                resource.setLink(getNullAsEmptyString(obj.get("link")));
+            }
+            if (obj.has("iconUrl")) {
+                resource.setIconUrl(getNullAsEmptyString(obj.get("iconUrl")));
+            }
+            if (obj.has("path")) {
+                resource.setPath(obj.get("path").getAsString());
+            }
+            if (obj.has("mimetype")) {
+                resource.setMimetype(obj.get("mimetype").getAsString());
+            }
+            if (obj.has("preview-available")) {
+                resource.setPreviewAvailable(obj.get("preview-available").getAsBoolean());
+            } else {
+                resource.setPreviewAvailable(false);
+            }
+
+        }, obj);
+        return resource;
+    }
+
     private static OcsComment parseOcsComment(JsonObject obj) {
         DeckLog.verbose(obj.toString());
         OcsComment comment = new OcsComment();
-        TraceableException.makeTraceableIfFails(() -> {
+        makeTraceableIfFails(() -> {
             JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
             if (data.isJsonArray()) {
                 for (JsonElement deckComment : data.getAsJsonArray()) {
@@ -121,7 +232,7 @@ public class JsonToEntityParser {
         DeckLog.verbose(data.toString());
         DeckComment deckComment = new DeckComment();
 
-        TraceableException.makeTraceableIfFails(() -> {
+        makeTraceableIfFails(() -> {
             JsonObject commentJson = data.getAsJsonObject();
 
             deckComment.setId(commentJson.get("id").getAsLong());
@@ -132,17 +243,18 @@ public class JsonToEntityParser {
             deckComment.setActorType(commentJson.get("actorType").getAsString());
             deckComment.setCreationDateTime(getTimestampFromString(commentJson.get("creationDateTime")));
 
-            if (commentJson.has("replyTo")){
-            JsonObject replyTo = commentJson.get("replyTo").getAsJsonObject();
-            deckComment.setParentId(replyTo.get("id").getAsLong());
-        }
+            if (commentJson.has("replyTo")) {
+                JsonObject replyTo = commentJson.get("replyTo").getAsJsonObject();
+                deckComment.setParentId(replyTo.get("id").getAsLong());
+            }
 
-        JsonElement mentions = commentJson.get("mentions");
-        if (mentions != null && mentions.isJsonArray()) {
-            for (JsonElement mention : mentions.getAsJsonArray()) {
-                deckComment.addMention(parseMention(mention));
+            JsonElement mentions = commentJson.get("mentions");
+            if (mentions != null && mentions.isJsonArray()) {
+                for (JsonElement mention : mentions.getAsJsonArray()) {
+                    deckComment.addMention(parseMention(mention));
+                }
             }
-        }}, data);
+        }, data);
 
         return deckComment;
     }
@@ -152,7 +264,7 @@ public class JsonToEntityParser {
         DeckLog.verbose(mentionJson.toString());
 
 
-        TraceableException.makeTraceableIfFails(() -> {
+        makeTraceableIfFails(() -> {
             JsonObject mentionObject = mentionJson.getAsJsonObject();
             mention.setMentionId(mentionObject.get("mentionId").getAsString());
             mention.setMentionType(mentionObject.get("mentionType").getAsString());
@@ -169,9 +281,10 @@ public class JsonToEntityParser {
         DeckLog.verbose(e.toString());
         Board board = new Board();
 
-        TraceableException.makeTraceableIfFails(() -> {
+        makeTraceableIfFails(() -> {
             board.setTitle(getNullAsEmptyString(e.get("title")));
             board.setColor(getNullAsEmptyString(e.get("color")));
+            board.setEtag(getNullAsNull(e.get("ETag")));
             board.setArchived(e.get("archived").getAsBoolean());
 
             board.setLastModified(getTimestampFromLong(e.get("lastModified")));
@@ -232,12 +345,19 @@ public class JsonToEntityParser {
                 }
             }
 
-            JsonElement owner = e.get("owner");
-            if (owner != null) {
-                if (owner.isJsonPrimitive()) {//TODO: remove if, let only else!
-                    DeckLog.verbose("owner is Primitive, skipping");
-                } else
-                    fullBoard.setOwner(parseUser(owner.getAsJsonObject()));
+            if (e.has("owner")) {
+                fullBoard.setOwner(parseUser(e.get("owner")));
+            }
+            if (e.has("users")) {
+                JsonElement users = e.get("users");
+                if (users != null && !users.isJsonNull() && users.isJsonArray()) {
+                    JsonArray usersArray = users.getAsJsonArray();
+                    List<User> usersList = new ArrayList<>();
+                    for (JsonElement userJson : usersArray) {
+                        usersList.add(parseUser(userJson));
+                    }
+                    fullBoard.setUsers(usersList);
+                }
             }
         }, e);
         return fullBoard;
@@ -248,8 +368,8 @@ public class JsonToEntityParser {
         AccessControl acl = new AccessControl();
 
         if (aclJson.has("participant") && !aclJson.get("participant").isJsonNull()) {
-            TraceableException.makeTraceableIfFails(() -> {
-                User participant = parseUser(aclJson.get("participant").getAsJsonObject());
+            makeTraceableIfFails(() -> {
+                User participant = parseUser(aclJson.get("participant"));
                 acl.setUser(participant);
                 acl.setType(aclJson.get("type").getAsLong());
                 acl.setBoardId(aclJson.get("boardId").getAsLong());
@@ -271,12 +391,13 @@ public class JsonToEntityParser {
         FullCard fullCard = new FullCard();
         Card card = new Card();
         fullCard.setCard(card);
-        TraceableException.makeTraceableIfFails(() -> {
+        makeTraceableIfFails(() -> {
             card.setId(e.get("id").getAsLong());
             card.setTitle(getNullAsEmptyString(e.get("title")));
             card.setDescription(getNullAsEmptyString(e.get("description")));
             card.setStackId(e.get("stackId").getAsLong());
             card.setType(getNullAsEmptyString(e.get("type")));
+            card.setEtag(getNullAsNull(e.get("ETag")));
             card.setLastModified(getTimestampFromLong(e.get("lastModified")));
             card.setCreatedAt(getTimestampFromLong(e.get("createdAt")));
             card.setDeletedAt(getTimestampFromLong(e.get("deletedAt")));
@@ -296,7 +417,7 @@ public class JsonToEntityParser {
                 for (JsonElement assignedUser : assignedUsers) {
                     JsonObject userJson = assignedUser.getAsJsonObject();
                     if (userJson.has("participant") && !userJson.get("participant").isJsonNull()) {
-                        users.add(parseUser(userJson.get("participant").getAsJsonObject()));
+                        users.add(parseUser(userJson.get("participant")));
                     }
                 }
                 fullCard.setAssignedUsers(users);
@@ -322,10 +443,7 @@ public class JsonToEntityParser {
             card.setCommentsUnread(e.get("commentsUnread").getAsInt());
             JsonElement owner = e.get("owner");
             if (owner != null) {
-                if (owner.isJsonPrimitive()) {//TODO: remove if, let only else!
-                    DeckLog.verbose("owner is Primitive, skipping");
-                } else
-                    fullCard.setOwner(parseUser(owner.getAsJsonObject()));
+                fullCard.setOwner(parseUser(owner));
             }
             card.setArchived(e.get("archived").getAsBoolean());
         }, e);
@@ -336,16 +454,17 @@ public class JsonToEntityParser {
     protected static Attachment parseAttachment(JsonObject e) {
         DeckLog.verbose(e.toString());
         Attachment a = new Attachment();
-        TraceableException.makeTraceableIfFails(() -> {
+        makeTraceableIfFails(() -> {
             a.setId(e.get("id").getAsLong());
             a.setCardId(e.get("cardId").getAsLong());
             a.setType(e.get("type").getAsString());
+            a.setEtag(getNullAsNull(e.get("ETag")));
             a.setData(e.get("data").getAsString());
             a.setLastModified(getTimestampFromLong(e.get("lastModified")));
             a.setCreatedAt(getTimestampFromLong(e.get("createdAt")));
             a.setCreatedBy(e.get("createdBy").getAsString());
             a.setDeletedAt(getTimestampFromLong(e.get("deletedAt")));
-            if (e.has("extendedData") && !e.get("extendedData").isJsonNull()) {
+            if (e.has("extendedData") && !e.get("extendedData").isJsonNull() && e.get("extendedData").isJsonObject()) {
                 JsonObject extendedData = e.getAsJsonObject("extendedData").getAsJsonObject();
                 a.setFilesize(extendedData.get("filesize").getAsLong());
                 a.setMimetype(extendedData.get("mimetype").getAsString());
@@ -364,14 +483,27 @@ public class JsonToEntityParser {
         return a;
     }
 
-    protected static User parseUser(JsonObject e) {
-        DeckLog.verbose(e.toString());
+    protected static User parseUser(JsonElement userElement) {
+        DeckLog.verbose(userElement.toString());
+        if (userElement.isJsonNull()) {
+            return null;
+        }
         User user = new User();
-        TraceableException.makeTraceableIfFails(() -> {
-            user.setDisplayname(getNullAsEmptyString(e.get("displayname")));
-            user.setPrimaryKey(getNullAsEmptyString(e.get("primaryKey")));
-            user.setUid(getNullAsEmptyString(e.get("uid")));
-        }, e);
+        makeTraceableIfFails(() -> {
+
+            if (userElement.isJsonPrimitive()) {
+                String uid = userElement.getAsString();
+                user.setDisplayname(uid);
+                user.setPrimaryKey(uid);
+                user.setUid(uid);
+            } else {
+                JsonObject userJson = userElement.getAsJsonObject();
+                user.setDisplayname(getNullAsEmptyString(userJson.get("displayname")));
+                user.setPrimaryKey(getNullAsEmptyString(userJson.get("primaryKey")));
+                user.setUid(getNullAsEmptyString(userJson.get("uid")));
+            }
+
+        }, userElement);
         return user;
     }
 
@@ -419,8 +551,8 @@ public class JsonToEntityParser {
                     }
                     if (caps.has("theming")) {
                         JsonObject theming = caps.getAsJsonObject("theming");
-                        capabilities.setColor(theming.get("color").getAsString());
-                        capabilities.setTextColor(theming.get("color-text").getAsString());
+                        capabilities.setColor(getColorAsInt(theming, "color"));
+                        capabilities.setTextColor(getColorAsInt(theming, "color-text"));
                     }
                 }
                 capabilities.setDeckVersion(Version.of(version));
@@ -429,31 +561,17 @@ public class JsonToEntityParser {
         return capabilities;
     }
 
-    protected static List<Activity> parseActivity(JsonObject e) {
-        DeckLog.verbose(e.toString());
-        List<Activity> activityList = new ArrayList<>();
-
-        TraceableException.makeTraceableIfFails(() -> {
-            if (e.has("ocs")) {
-                JsonObject ocs = e.getAsJsonObject("ocs");
-                if (ocs.has("data")) {
-                    JsonArray data = ocs.getAsJsonArray("data");
-                    for (JsonElement activityJson : data) {
-                        Activity activity = new Activity();
-                        JsonObject activityObject = activityJson.getAsJsonObject();
-
-                        activity.setId(activityObject.get("activity_id").getAsLong());
-                        activity.setType(ActivityType.findByPath(getNullAsEmptyString(activityObject.get("icon"))).getId());
-                        activity.setSubject(getNullAsEmptyString(activityObject.get("subject")));
-                        activity.setCardId(activityObject.get("object_id").getAsLong());
-                        activity.setLastModified(getTimestampFromString(activityObject.get("datetime")));
-
-                        activityList.add(activity);
-                    }
-                }
+    private static int getColorAsInt(JsonObject element, String field) {
+        String rawString = getNullAsEmptyString(element.get(field));
+        try {
+            if (!rawString.trim().isEmpty()) {
+                String colorAsString = ColorUtil.INSTANCE.formatColorToParsableHexString(rawString);
+                return Color.parseColor(colorAsString);
             }
-        }, e);
-        return activityList;
+        } catch (Exception e) {
+            // Do mostly nothing, return default value
+        }
+        return Color.GRAY;
     }
 
     protected static FullStack parseStack(JsonObject e) {
@@ -461,10 +579,11 @@ public class JsonToEntityParser {
         FullStack fullStack = new FullStack();
         Stack stack = new Stack();
         fullStack.setStack(stack);
-        TraceableException.makeTraceableIfFails(() -> {
+        makeTraceableIfFails(() -> {
             stack.setTitle(getNullAsEmptyString(e.get("title")));
             stack.setBoardId(e.get("boardId").getAsLong());
             stack.setId(e.get("id").getAsLong());
+            stack.setEtag(getNullAsNull(e.get("ETag")));
             stack.setLastModified(getTimestampFromLong(e.get("lastModified")));
             stack.setDeletedAt(getTimestampFromLong(e.get("deletedAt")));
             if (e.has("order") && !e.get("order").isJsonNull()) {
@@ -485,37 +604,70 @@ public class JsonToEntityParser {
         return fullStack;
     }
 
+    protected static List<Activity> parseActivity(JsonObject e) {
+        DeckLog.verbose(e.toString());
+        List<Activity> activityList = new ArrayList<>();
+
+        makeTraceableIfFails(() -> {
+            if (e.has("ocs")) {
+                JsonObject ocs = e.getAsJsonObject("ocs");
+                if (ocs.has("data")) {
+                    JsonArray data = ocs.getAsJsonArray("data");
+                    for (JsonElement activityJson : data) {
+                        Activity activity = new Activity();
+                        JsonObject activityObject = activityJson.getAsJsonObject();
+
+                        activity.setId(activityObject.get("activity_id").getAsLong());
+                        activity.setType(ActivityType.findByPath(getNullAsEmptyString(activityObject.get("icon"))).getId());
+                        activity.setSubject(getNullAsEmptyString(activityObject.get("subject")));
+                        activity.setCardId(activityObject.get("object_id").getAsLong());
+                        activity.setEtag(getNullAsNull(e.get("ETag")));
+                        activity.setLastModified(getTimestampFromString(activityObject.get("datetime")));
+
+                        activityList.add(activity);
+                    }
+                }
+            }
+        }, e);
+        return activityList;
+    }
+
     protected static Label parseLabel(JsonObject e) {
         DeckLog.verbose(e.toString());
         Label label = new Label();
-        TraceableException.makeTraceableIfFails(() -> {
+        makeTraceableIfFails(() -> {
             label.setId(e.get("id").getAsLong());
             //todo: last modified!
 //          label.setLastModified(get);
             label.setTitle(getNullAsEmptyString(e.get("title")));
-            label.setColor(getNullAsEmptyString(e.get("color")));
+            label.setEtag(getNullAsNull(e.get("ETag")));
+            label.setColor(getColorAsInt(e, "color"));
         }, e);
         return label;
     }
 
     private static String getNullAsEmptyString(JsonElement jsonElement) {
-        return jsonElement.isJsonNull() ? "" : jsonElement.getAsString();
+        return jsonElement == null || jsonElement.isJsonNull() ? "" : jsonElement.getAsString();
+    }
+
+    private static String getNullAsNull(JsonElement jsonElement) {
+        return jsonElement == null || jsonElement.isJsonNull() ? null : jsonElement.getAsString();
     }
 
-    private static Date getTimestampFromString(JsonElement jsonElement) {
+    private static Instant getTimestampFromString(JsonElement jsonElement) {
         if (jsonElement.isJsonNull()) {
             return null;
         } else {
             String dateAsString = jsonElement.getAsString();
-            return DateTimeUtils.toDate(ZonedDateTime.from(DateTimeFormatter.ISO_DATE_TIME.parse(dateAsString)).toInstant());
+            return ZonedDateTime.from(DateTimeFormatter.ISO_DATE_TIME.parse(dateAsString)).toInstant();
         }
     }
 
-    private static Date getTimestampFromLong(JsonElement jsonElement) {
+    private static Instant getTimestampFromLong(JsonElement jsonElement) {
         if (jsonElement.isJsonNull()) {
             return null;
         } else {
-            return new Date(jsonElement.getAsLong() * 1000);
+            return Instant.ofEpochMilli(jsonElement.getAsLong() * 1000);
         }
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/LastSyncUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/LastSyncUtil.java
index 1d44bfe13..1492d78ac 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/LastSyncUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/LastSyncUtil.java
@@ -3,7 +3,7 @@ package it.niedermann.nextcloud.deck.api;
 import android.content.Context;
 import android.content.SharedPreferences;
 
-import java.util.Date;
+import java.time.Instant;
 
 import it.niedermann.nextcloud.deck.R;
 
@@ -22,19 +22,19 @@ public class LastSyncUtil {
 
     }
 
-    public static long getLastSync(long accountId){
+    public static long getLastSync(long accountId) {
         return INSTANCE.lastSyncPref.getLong(getSyncKeyForAccount(accountId), 0L);
     }
 
-    public static Date getLastSyncDate(long accountId){
-        return new Date(getLastSync(accountId));
+    public static Instant getLastSyncDate(long accountId) {
+        return Instant.ofEpochMilli(getLastSync(accountId));
     }
 
-    public static void setLastSyncDate(long accountId, Date value){
-        INSTANCE.lastSyncPref.edit().putLong(getSyncKeyForAccount(accountId), value.getTime()).apply();
+    public static void setLastSyncDate(long accountId, Instant value) {
+        INSTANCE.lastSyncPref.edit().putLong(getSyncKeyForAccount(accountId), value.toEpochMilli()).apply();
     }
 
-    public static void resetLastSyncDate(long accountId){
+    public static void resetLastSyncDate(long accountId) {
         INSTANCE.lastSyncPref.edit().remove(getSyncKeyForAccount(accountId)).apply();
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudServerAPI.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudServerAPI.java
index d69ee8513..7b93ace49 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudServerAPI.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudServerAPI.java
@@ -1,6 +1,8 @@
 package it.niedermann.nextcloud.deck.api;
 
 
+import com.nextcloud.android.sso.api.ParsedResponse;
+
 import java.util.List;
 
 import io.reactivex.Observable;
@@ -8,11 +10,14 @@ import it.niedermann.nextcloud.deck.model.ocs.Activity;
 import it.niedermann.nextcloud.deck.model.ocs.Capabilities;
 import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.OcsComment;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectList;
+import it.niedermann.nextcloud.deck.model.ocs.user.GroupMemberUIDs;
 import it.niedermann.nextcloud.deck.model.ocs.user.OcsUser;
 import it.niedermann.nextcloud.deck.model.ocs.user.OcsUserList;
 import retrofit2.http.Body;
 import retrofit2.http.DELETE;
 import retrofit2.http.GET;
+import retrofit2.http.Header;
 import retrofit2.http.Headers;
 import retrofit2.http.POST;
 import retrofit2.http.PUT;
@@ -22,13 +27,19 @@ import retrofit2.http.Query;
 public interface NextcloudServerAPI {
 
     @GET("cloud/capabilities?format=json")
-    Observable<Capabilities> getCapabilities();
+    Observable<ParsedResponse<Capabilities>> getCapabilities(@Header("If-None-Match") String eTag);
+
+    @GET("collaboration/resources/deck-card/{cardId}?format=json")
+    Observable<OcsProjectList> getProjectsForCard(@Path("cardId") long cardId);
+
+    @GET("apps/files_sharing/api/v1/sharees?format=json&perPage=20&itemType=0%2C1%2C7")
+    Observable<OcsUserList> searchUser(@Query("search") String searchTerm);
 
-    @GET("cloud/users?format=json")
-    Observable<OcsUserList> getAllUsers();
+    @GET("cloud/groups/{search}?format=json")
+    Observable<GroupMemberUIDs> searchGroupMembers(@Path("search") String groupUid);
 
-    @GET("cloud/users/{uid}?format=json")
-    Observable<OcsUser> getUserDetails(@Path("uid") String uid);
+    @GET("cloud/users/{search}?format=json")
+    Observable<OcsUser> getSingleUserData(@Path("search") String userUid);
 
     @GET("apps/activity/api/v2/activity/filter?format=json&object_type=deck_card&limit=50&since=-1&sort=asc")
     Observable<List<Activity>> getActivitiesForCard(@Query("object_id") long cardId);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/json/JsonColorSerializer.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/json/JsonColorSerializer.java
new file mode 100644
index 000000000..5169e7f5e
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/json/JsonColorSerializer.java
@@ -0,0 +1,26 @@
+package it.niedermann.nextcloud.deck.api.json;
+
+import com.google.gson.TypeAdapter;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+
+import java.io.IOException;
+
+import it.niedermann.android.util.ColorUtil;
+
+public class JsonColorSerializer extends TypeAdapter<Integer> {
+    @Override
+    public void write(JsonWriter out, Integer value) throws IOException {
+        if (value == null) {
+            out.nullValue();
+        } else {
+            out.value(ColorUtil.INSTANCE.intColorToHexString(value));
+        }
+    }
+
+    @Override
+    public Integer read(JsonReader in) throws IOException {
+        // currently not needed
+        return null;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/DeckException.java b/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/DeckException.java
index 8c2904d2b..0512f8a60 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/DeckException.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/DeckException.java
@@ -5,6 +5,8 @@ public class DeckException extends IllegalArgumentException {
     public enum Hint {
         CAPABILITIES_NOT_PARSABLE,
         CAPABILITIES_VERSION_NOT_PARSABLE,
+        UNKNOWN_ACCOUNT_USER_ID,
+        DEPENDENCY_NOT_SYNCED_YET
     }
 
     private Hint hint;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/TraceableException.java b/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/TraceableException.java
index a53ce8c1f..8d436477d 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/TraceableException.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/exceptions/TraceableException.java
@@ -11,22 +11,24 @@ public class TraceableException extends RuntimeException {
     public static void makeTraceableIfFails(Runnable runnable, Object... args) {
         try {
             runnable.run();
+        } catch (TraceableException t) {
+            throw t;
         } catch (Throwable t) {
-            String message = "Sorry, a wild error appeared!\n" +
-                    "### If you want to tell us about the following issue, " +
-                    "please make sure to censor sensitive data beforehand! ###\n" +
-                    "Failed to run traceable code";
+            final StringBuilder message = new StringBuilder("Sorry, a wild error appeared!\n\n" +
+                    "⚠️ If you want to tell us about the following issue, " +
+                    "please make sure to censor sensitive data beforehand! ⚠️\n\n" +
+                    "Failed to run traceable code");
             if (args != null && args.length > 0) {
-                message += " with arguments:\n";
+                message.append(" with arguments:\n");
                 for (Object arg : args) {
-                    message += (arg == null ? "null" : arg.toString())+"\n";
+                    message.append(arg == null ? "null" : arg.toString()).append("\n");
                 }
             } else {
-                message += ":\n";
+                message.append(":\n");
             }
 
-            message += "Cause: " + t.getLocalizedMessage();
-            TraceableException ex = new TraceableException(message, t);
+            message.append("Cause: ").append(t.getLocalizedMessage());
+            TraceableException ex = new TraceableException(message.toString(), t);
             DeckLog.logError(ex);
             throw ex;
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/AccessControl.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/AccessControl.java
index 299dd7ca0..e2a3ccc3b 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/AccessControl.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/AccessControl.java
@@ -8,6 +8,7 @@ import androidx.room.Index;
 import com.google.gson.annotations.SerializedName;
 
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
+import it.niedermann.nextcloud.deck.model.ocs.user.GroupMemberUIDs;
 
 @Entity(inheritSuperIndices = true,
     indices = {
@@ -35,6 +36,8 @@ public class AccessControl extends AbstractRemoteEntity {
     @Ignore
     @SerializedName("participant")
     private User user;
+    @Ignore
+    private GroupMemberUIDs groupMemberUIDs;
 
     public AccessControl() {
         super();
@@ -115,6 +118,14 @@ public class AccessControl extends AbstractRemoteEntity {
         this.user = user;
     }
 
+    public GroupMemberUIDs getGroupMemberUIDs() {
+        return groupMemberUIDs;
+    }
+
+    public void setGroupMemberUIDs(GroupMemberUIDs groupMemberUIDs) {
+        this.groupMemberUIDs = groupMemberUIDs;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/Account.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/Account.java
index ba8fb72b7..8abcbced7 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/Account.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/Account.java
@@ -2,6 +2,7 @@ package it.niedermann.nextcloud.deck.model;
 
 import android.net.Uri;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Px;
 import androidx.room.ColumnInfo;
@@ -18,7 +19,6 @@ import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.model.ocs.Capabilities;
 import it.niedermann.nextcloud.deck.model.ocs.Version;
 import it.niedermann.nextcloud.deck.ui.accountswitcher.AccountSwitcherDialog;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
 
 @Entity(indices = {@Index(value = "name", unique = true)})
 public class Account implements Serializable {
@@ -38,12 +38,12 @@ public class Account implements Serializable {
     private String url;
 
     @NonNull
-    @ColumnInfo(defaultValue = "#0082c9")
-    private String color = "#0082c9";
+    @ColumnInfo(defaultValue = "0")
+    private Integer color = 0;
 
     @NonNull
-    @ColumnInfo(defaultValue = "#ffffff")
-    private String textColor = "#ffffff";
+    @ColumnInfo(defaultValue = "0")
+    private Integer textColor = 0;
 
     @NonNull
     @ColumnInfo(defaultValue = "0.6.4")
@@ -53,6 +53,9 @@ public class Account implements Serializable {
     @ColumnInfo(defaultValue = "0")
     private boolean maintenanceEnabled = false;
 
+    private String etag;
+    private String boardsEtag;
+
     @Ignore
     public Account(Long id, @NonNull String name, @NonNull String userName, @NonNull String url) {
         this(name, userName, url);
@@ -60,7 +63,7 @@ public class Account implements Serializable {
     }
 
     @Ignore
-    public Account(String name, String userName, String url) {
+    public Account(@NonNull String name, @NonNull String userName, @NonNull String url) {
         this.name = name;
         this.userName = userName;
         this.url = url;
@@ -74,22 +77,29 @@ public class Account implements Serializable {
     public Account() {
     }
 
-    public void applyCapabilities(Capabilities capabilities) {
+    public void applyCapabilities(Capabilities capabilities, String eTag) {
+        if (capabilities == null) {
+            maintenanceEnabled = true;
+            return;
+        }
         maintenanceEnabled = capabilities.isMaintenanceEnabled();
         if (!isMaintenanceEnabled()) {
             try {
                 // Nextcloud might return color format #000 which cannot be parsed by Color.parseColor()
                 // https://github.com/stefan-niedermann/nextcloud-deck/issues/466
-                color = ColorUtil.formatColorToParsableHexString(capabilities.getColor());
-                textColor = ColorUtil.formatColorToParsableHexString(capabilities.getTextColor());
+                color = capabilities.getColor();
+                textColor = capabilities.getTextColor();
             } catch (Exception e) {
                 DeckLog.logError(e);
-                color = "#0082c9";
-                color = "#ffffff";
+                color = 0;
+                color = 0;
             }
             if (capabilities.getDeckVersion() != null) {
                 serverDeckVersion = capabilities.getDeckVersion().getOriginalVersion();
             }
+            if (eTag != null) {
+                this.etag = eTag;
+            }
         }
     }
 
@@ -132,21 +142,23 @@ public class Account implements Serializable {
         return serialVersionUID;
     }
 
+    @ColorInt
     @NonNull
-    public String getColor() {
+    public Integer getColor() {
         return color;
     }
 
-    public void setColor(@NonNull String color) {
+    public void setColor(@NonNull Integer color) {
         this.color = color;
     }
 
     @NonNull
-    public String getTextColor() {
+    public Integer getTextColor() {
         return textColor;
     }
 
-    public void setTextColor(@NonNull String textColor) {
+    @Deprecated
+    public void setTextColor(@NonNull Integer textColor) {
         this.textColor = textColor;
     }
 
@@ -171,6 +183,31 @@ public class Account implements Serializable {
         this.maintenanceEnabled = maintenanceEnabled;
     }
 
+    public String getEtag() {
+        return etag;
+    }
+
+    public void setEtag(String etag) {
+        this.etag = etag;
+    }
+
+    public String getBoardsEtag() {
+        return boardsEtag;
+    }
+
+    public void setBoardsEtag(String boardsEtag) {
+        this.boardsEtag = boardsEtag;
+    }
+
+    /**
+     * A cache buster parameter is added for duplicate account names on different hosts which shall be fetched from the same {@link SingleSignOnAccount} (e. g. {@link AccountSwitcherDialog})
+     *
+     * @return an {@link String} to fetch the avatar for this account.
+     */
+    public String getAvatarUrl(@Px int size) {
+        return getUrl() + "/index.php/avatar/" + Uri.encode(getUserName()) + "/" + size;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
@@ -185,16 +222,8 @@ public class Account implements Serializable {
         if (!url.equals(account.url)) return false;
         if (!color.equals(account.color)) return false;
         if (!textColor.equals(account.textColor)) return false;
-        return serverDeckVersion.equals(account.serverDeckVersion);
-    }
-
-    /**
-     * A cache buster parameter is added for duplicate account names on different hosts which shall be fetched from the same {@link SingleSignOnAccount} (e. g. {@link AccountSwitcherDialog})
-     *
-     * @return an {@link String} to fetch the avatar for this account.
-     */
-    public String getAvatarUrl(@Px int size) {
-        return getUrl() + "/index.php/avatar/" + Uri.encode(getUserName()) + "/" + size;
+        if (!serverDeckVersion.equals(account.serverDeckVersion)) return false;
+        return etag != null ? etag.equals(account.etag) : account.etag == null;
     }
 
     @Override
@@ -207,6 +236,7 @@ public class Account implements Serializable {
         result = 31 * result + textColor.hashCode();
         result = 31 * result + serverDeckVersion.hashCode();
         result = 31 * result + (maintenanceEnabled ? 1 : 0);
+        result = 31 * result + (etag != null ? etag.hashCode() : 0);
         return result;
     }
 
@@ -221,6 +251,7 @@ public class Account implements Serializable {
                 ", textColor='" + textColor + '\'' +
                 ", serverDeckVersion='" + serverDeckVersion + '\'' +
                 ", maintenanceEnabled=" + maintenanceEnabled +
+                ", eTag='" + etag + '\'' +
                 '}';
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/Attachment.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/Attachment.java
index 91192f597..7eabcbe70 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/Attachment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/Attachment.java
@@ -2,32 +2,33 @@ package it.niedermann.nextcloud.deck.model;
 
 import androidx.room.Entity;
 import androidx.room.ForeignKey;
+import androidx.room.Ignore;
 import androidx.room.Index;
 
 import java.io.Serializable;
-import java.util.Date;
+import java.time.Instant;
 
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
 
 @Entity(inheritSuperIndices = true,
         indices = {@Index("cardId")},
         foreignKeys = {
-        @ForeignKey(
-            entity = Card.class,
-            parentColumns = "localId",
-            childColumns = "cardId",
-            onDelete = ForeignKey.CASCADE
-        )
-    }
+                @ForeignKey(
+                        entity = Card.class,
+                        parentColumns = "localId",
+                        childColumns = "cardId",
+                        onDelete = ForeignKey.CASCADE
+                )
+        }
 )
 public class Attachment extends AbstractRemoteEntity implements Comparable<Attachment>, Serializable {
 
     private long cardId;
     private String type = "deck_file";
     private String data;
-    private Date createdAt;
+    private Instant createdAt;
     private String createdBy;
-    private Date deletedAt;
+    private Instant deletedAt;
     private long filesize;
     private String mimetype;
     private String dirname;
@@ -35,6 +36,9 @@ public class Attachment extends AbstractRemoteEntity implements Comparable<Attac
     private String extension;
     private String filename;
     private String localPath;
+    // TODO should probably be a Long... depends on https://github.com/nextcloud/deck/pull/2638
+    @Ignore
+    private String fileId;
 
     public long getCardId() {
         return cardId;
@@ -60,11 +64,11 @@ public class Attachment extends AbstractRemoteEntity implements Comparable<Attac
         this.data = data;
     }
 
-    public Date getCreatedAt() {
+    public Instant getCreatedAt() {
         return createdAt;
     }
 
-    public void setCreatedAt(Date createdAt) {
+    public void setCreatedAt(Instant createdAt) {
         this.createdAt = createdAt;
     }
 
@@ -76,11 +80,11 @@ public class Attachment extends AbstractRemoteEntity implements Comparable<Attac
         this.createdBy = createdBy;
     }
 
-    public Date getDeletedAt() {
+    public Instant getDeletedAt() {
         return deletedAt;
     }
 
-    public void setDeletedAt(Date deletedAt) {
+    public void setDeletedAt(Instant deletedAt) {
         this.deletedAt = deletedAt;
     }
 
@@ -140,6 +144,22 @@ public class Attachment extends AbstractRemoteEntity implements Comparable<Attac
         this.localPath = localPath;
     }
 
+    /**
+     * TODO depends on https://github.com/nextcloud/deck/pull/2638
+     */
+    @Ignore
+    public String getFileId() {
+        return this.fileId;
+    }
+
+    /**
+     * TODO depends on https://github.com/nextcloud/deck/pull/2638
+     */
+    @Ignore
+    public void setFileId(String fileId) {
+        this.fileId = fileId;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
@@ -202,7 +222,7 @@ public class Attachment extends AbstractRemoteEntity implements Comparable<Attac
     private static int longToComparsionResult(long diff) {
         if (diff > 0) {
             return 1;
-        } else if(diff < 0) {
+        } else if (diff < 0) {
             return -1;
         }
         return 0;
@@ -210,18 +230,18 @@ public class Attachment extends AbstractRemoteEntity implements Comparable<Attac
 
     public long getModificationTimeForComparsion() {
         if (lastModifiedLocal != null) {
-            return lastModifiedLocal.getTime();
+            return lastModifiedLocal.toEpochMilli();
         }
         if (lastModified != null) {
-            return lastModified.getTime();
+            return lastModified.toEpochMilli();
         }
-        return new Date().getTime();
+        return Instant.now().toEpochMilli();
     }
 
     public long getCreationTimeForComparsion() {
         if (createdAt != null) {
-            return createdAt.getTime();
+            return createdAt.toEpochMilli();
         }
-        return new Date().getTime();
+        return Instant.now().toEpochMilli();
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/Board.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/Board.java
index 29afe844b..27dcd1df8 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/Board.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/Board.java
@@ -1,17 +1,23 @@
 package it.niedermann.nextcloud.deck.model;
 
+import android.graphics.Color;
+
+import androidx.annotation.ColorInt;
 import androidx.room.Entity;
 import androidx.room.ForeignKey;
 import androidx.room.Ignore;
 import androidx.room.Index;
 
+import com.google.gson.annotations.JsonAdapter;
+
 import java.io.Serializable;
-import java.util.Date;
+import java.time.Instant;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.api.json.JsonColorSerializer;
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
 
 @Entity(
         inheritSuperIndices = true,
@@ -31,20 +37,18 @@ public class Board extends AbstractRemoteEntity implements Serializable {
     }
 
     @Ignore
-    public Board(String title, String color) {
-        this.title = title;
+    public Board(String title, @ColorInt int color) {
+        setTitle(title);
         setColor(color);
     }
 
     private String title;
     private long ownerId;
-    /**
-     * Deck App sends color strings without leading # character
-     */
-    private String color;
+    @JsonAdapter(JsonColorSerializer.class)
+    private Integer color;
     private boolean archived;
     private int shared;
-    private Date deletedAt;
+    private Instant deletedAt;
     private boolean permissionRead = false;
     private boolean permissionEdit = false;
     private boolean permissionManage = false;
@@ -52,22 +56,22 @@ public class Board extends AbstractRemoteEntity implements Serializable {
 
 
     @Override
-    public Date getLastModified() {
+    public Instant getLastModified() {
         return lastModified;
     }
 
     @Override
-    public void setLastModified(Date lastModified) {
+    public void setLastModified(Instant lastModified) {
         this.lastModified = lastModified;
     }
 
     @Override
-    public Date getLastModifiedLocal() {
+    public Instant getLastModifiedLocal() {
         return lastModifiedLocal;
     }
 
     @Override
-    public void setLastModifiedLocal(Date lastModifiedLocal) {
+    public void setLastModifiedLocal(Instant lastModifiedLocal) {
         this.lastModifiedLocal = lastModifiedLocal;
     }
 
@@ -79,21 +83,25 @@ public class Board extends AbstractRemoteEntity implements Serializable {
         this.id = id;
     }
 
-    public String getColor() {
+    @ColorInt
+    public Integer getColor() {
         return color;
     }
 
+
     public void setColor(String color) {
         try {
-            // Nextcloud might return color format #000 which cannot be parsed by Color.parseColor()
-            // https://github.com/stefan-niedermann/nextcloud-deck/issues/466
-            this.color = ColorUtil.formatColorToParsableHexString(color).substring(1);
+            setColor(Color.parseColor(ColorUtil.INSTANCE.formatColorToParsableHexString(color)));
         } catch (Exception e) {
             DeckLog.logError(e);
-            this.color = "757575";
+            setColor(Color.GRAY);
         }
     }
 
+    public void setColor(@ColorInt Integer color) {
+        this.color = color;
+    }
+
     public boolean isArchived() {
         return archived;
     }
@@ -114,11 +122,11 @@ public class Board extends AbstractRemoteEntity implements Serializable {
         this.shared = shared;
     }
 
-    public Date getDeletedAt() {
+    public Instant getDeletedAt() {
         return deletedAt;
     }
 
-    public void setDeletedAt(Date deletedAt) {
+    public void setDeletedAt(Instant deletedAt) {
         this.deletedAt = deletedAt;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/Card.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/Card.java
index 732ccfc50..6f2b70020 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/Card.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/Card.java
@@ -8,7 +8,7 @@ import androidx.room.Index;
 
 import com.google.gson.annotations.SerializedName;
 
-import java.util.Date;
+import java.time.Instant;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -16,22 +16,23 @@ import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
 
 @Entity(inheritSuperIndices = true,
-    indices = {
-        @Index(value = "accountId", name = "card_accID"),
-        @Index("stackId")
-    },
-    foreignKeys = {
-        @ForeignKey(
-            entity = Stack.class,
-            parentColumns = "localId",
-            childColumns = "stackId", onDelete = ForeignKey.CASCADE
-        )
-    }
+        indices = {
+                @Index(value = "accountId", name = "card_accID"),
+                @Index("stackId")
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = Stack.class,
+                        parentColumns = "localId",
+                        childColumns = "stackId", onDelete = ForeignKey.CASCADE
+                )
+        }
 )
 public class Card extends AbstractRemoteEntity {
 
     private static Pattern PATTERN_MD_TASK = Pattern.compile("\\[([xX ])]");
-    public class TaskStatus {
+
+    public static class TaskStatus {
         public int taskCount;
         public int doneCount;
 
@@ -49,20 +50,21 @@ public class Card extends AbstractRemoteEntity {
     @NonNull
     private Long stackId;
     private String type;
-    private Date createdAt;
-    private Date deletedAt;
+    private Instant createdAt;
+    private Instant deletedAt;
     private int attachmentCount;
 
     private Long userId;
     private int order;
     private boolean archived;
     @SerializedName("duedate")
-    private Date dueDate;
+    private Instant dueDate;
     private boolean notified;
     private int overdue;
     private int commentsUnread;
 
-    public Card() {}
+    public Card() {
+    }
 
     @Ignore
     public Card(String title, String description, long stackId) {
@@ -89,15 +91,15 @@ public class Card extends AbstractRemoteEntity {
         this.commentsUnread = card.getCommentsUnread();
     }
 
-    public TaskStatus getTaskStatus(){
-        if (taskStatus == null){
+    public TaskStatus getTaskStatus() {
+        if (taskStatus == null) {
             int count = 0, done = 0;
             if (description != null) {
                 Matcher matcher = PATTERN_MD_TASK.matcher(description);
-                while (matcher.find()){
+                while (matcher.find()) {
                     count++;
                     char c = matcher.group().charAt(1);
-                    if (c == 'x' || c == 'X'){
+                    if (c == 'x' || c == 'X') {
                         done++;
                     }
                 }
@@ -164,19 +166,19 @@ public class Card extends AbstractRemoteEntity {
         this.type = type;
     }
 
-    public Date getCreatedAt() {
+    public Instant getCreatedAt() {
         return createdAt;
     }
 
-    public void setCreatedAt(Date createdAt) {
+    public void setCreatedAt(Instant createdAt) {
         this.createdAt = createdAt;
     }
 
-    public Date getDeletedAt() {
+    public Instant getDeletedAt() {
         return deletedAt;
     }
 
-    public void setDeletedAt(Date deletedAt) {
+    public void setDeletedAt(Instant deletedAt) {
         this.deletedAt = deletedAt;
     }
 
@@ -200,12 +202,12 @@ public class Card extends AbstractRemoteEntity {
         this.archived = archived;
     }
 
-    public Date getDueDate() {
+    public Instant getDueDate() {
         return dueDate;
     }
 
-    public void setDueDate(Date dueDate) {
-        this.dueDate = dueDate;
+    public void setDueDate(Instant dateTime) {
+        this.dueDate = dateTime;
     }
 
     public int getOverdue() {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/Label.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/Label.java
index 0d97ce5a0..da24edb5a 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/Label.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/Label.java
@@ -1,27 +1,41 @@
 package it.niedermann.nextcloud.deck.model;
 
+import android.graphics.Color;
+
+import androidx.annotation.ColorInt;
+import androidx.annotation.NonNull;
+import androidx.room.ColumnInfo;
 import androidx.room.Entity;
 import androidx.room.ForeignKey;
 import androidx.room.Index;
 
+import com.google.gson.annotations.JsonAdapter;
+
 import java.io.Serializable;
 
+import it.niedermann.android.util.ColorUtil;
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.api.json.JsonColorSerializer;
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
 
 @Entity(inheritSuperIndices = true,
         indices = {@Index("boardId"), @Index(value = {"boardId", "title"}, unique = true, name = "idx_label_title_unique")},
         foreignKeys = {
-        @ForeignKey(
-            entity = Board.class,
-            parentColumns = "localId",
-            childColumns = "boardId",
-            onDelete = ForeignKey.CASCADE
-        )
-    }
+                @ForeignKey(
+                        entity = Board.class,
+                        parentColumns = "localId",
+                        childColumns = "boardId",
+                        onDelete = ForeignKey.CASCADE
+                )
+        }
 )
 public class Label extends AbstractRemoteEntity implements Serializable {
     private String title;
-    private String color;
+
+    @JsonAdapter(JsonColorSerializer.class)
+    @NonNull
+    @ColumnInfo(defaultValue = "0")
+    private Integer color;
     private long boardId;
 
     public Label() {
@@ -42,14 +56,25 @@ public class Label extends AbstractRemoteEntity implements Serializable {
         this.title = title;
     }
 
-    public String getColor() {
+    @NonNull
+    @ColorInt
+    public Integer getColor() {
         return color;
     }
 
-    public void setColor(String color) {
+    public void setColor(@NonNull @ColorInt Integer color) {
         this.color = color;
     }
 
+    public void setColor(String color) {
+        try {
+            setColor(Color.parseColor(ColorUtil.INSTANCE.formatColorToParsableHexString(color)));
+        } catch (Exception e) {
+            DeckLog.logError(e);
+            setColor(Color.GRAY);
+        }
+    }
+
     public long getBoardId() {
         return boardId;
     }
@@ -62,18 +87,20 @@ public class Label extends AbstractRemoteEntity implements Serializable {
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
+        if (!super.equals(o)) return false;
 
         Label label = (Label) o;
 
         if (boardId != label.boardId) return false;
         if (title != null ? !title.equals(label.title) : label.title != null) return false;
-        return color != null ? color.equals(label.color) : label.color == null;
+        return color.equals(label.color);
     }
 
     @Override
     public int hashCode() {
-        int result = title != null ? title.hashCode() : 0;
-        result = 31 * result + (color != null ? color.hashCode() : 0);
+        int result = super.hashCode();
+        result = 31 * result + (title != null ? title.hashCode() : 0);
+        result = 31 * result + color.hashCode();
         result = 31 * result + (int) (boardId ^ (boardId >>> 32));
         return result;
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/Stack.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/Stack.java
index 330ec16d7..00f054605 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/Stack.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/Stack.java
@@ -1,12 +1,11 @@
 package it.niedermann.nextcloud.deck.model;
 
-import androidx.annotation.NonNull;
 import androidx.room.Entity;
 import androidx.room.ForeignKey;
 import androidx.room.Ignore;
 import androidx.room.Index;
 
-import java.util.Date;
+import java.time.Instant;
 
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
 
@@ -35,12 +34,10 @@ public class Stack extends AbstractRemoteEntity {
 
     private String title;
 
-    @NonNull
     private long boardId;
 
-    private Date deletedAt;
+    private Instant deletedAt;
 
-    @NonNull
     private int order;
 //
 //    @ToMany
@@ -64,11 +61,11 @@ public class Stack extends AbstractRemoteEntity {
         this.boardId = boardId;
     }
 
-    public Date getDeletedAt() {
+    public Instant getDeletedAt() {
         return deletedAt;
     }
 
-    public void setDeletedAt(Date deletedAt) {
+    public void setDeletedAt(Instant deletedAt) {
         this.deletedAt = deletedAt;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/User.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/User.java
index cfb48d543..fd318ce7a 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/User.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/User.java
@@ -4,10 +4,12 @@ import androidx.room.Entity;
 import androidx.room.Ignore;
 import androidx.room.Index;
 
+import java.io.Serializable;
+
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
 
 @Entity(inheritSuperIndices = true, indices = {@Index(value = "uid", name = "user_uid")})
-public class User extends AbstractRemoteEntity {
+public class User extends AbstractRemoteEntity implements Serializable {
 
 
     private String primaryKey;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/appwidgets/StackWidgetModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/appwidgets/StackWidgetModel.java
new file mode 100644
index 000000000..fb7a74076
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/appwidgets/StackWidgetModel.java
@@ -0,0 +1,68 @@
+package it.niedermann.nextcloud.deck.model.appwidgets;
+
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Index;
+import androidx.room.PrimaryKey;
+
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Stack;
+
+@Entity(
+        indices = {
+                @Index("stackId"),
+                @Index("accountId")
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = Account.class,
+                        parentColumns = "id",
+                        childColumns = "accountId", onDelete = ForeignKey.CASCADE
+                ),
+                @ForeignKey(
+                        entity = Stack.class,
+                        parentColumns = "localId",
+                        childColumns = "stackId", onDelete = ForeignKey.CASCADE
+                )
+        }
+)
+public class StackWidgetModel {
+
+    @PrimaryKey()
+    private Integer appWidgetId;
+    private Long accountId;
+    private Long stackId;
+    private boolean darkTheme;
+
+    public Integer getAppWidgetId() {
+        return appWidgetId;
+    }
+
+    public void setAppWidgetId(Integer appWidgetId) {
+        this.appWidgetId = appWidgetId;
+    }
+
+    public Long getAccountId() {
+        return accountId;
+    }
+
+    public void setAccountId(Long accountId) {
+        this.accountId = accountId;
+    }
+
+    public Long getStackId() {
+        return stackId;
+    }
+
+    public void setStackId(Long stackId) {
+        this.stackId = stackId;
+    }
+
+    public boolean getDarkTheme() {
+        return darkTheme;
+    }
+
+    public void setDarkTheme(boolean darkTheme) {
+        this.darkTheme = darkTheme;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullBoard.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullBoard.java
index 31ad21f16..f9f1643ff 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullBoard.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullBoard.java
@@ -1,5 +1,6 @@
 package it.niedermann.nextcloud.deck.model.full;
 
+import androidx.annotation.NonNull;
 import androidx.room.Embedded;
 import androidx.room.Ignore;
 import androidx.room.Relation;
@@ -29,6 +30,8 @@ public class FullBoard implements IRemoteEntity {
     @Relation(entity = Stack.class, parentColumn = "localId", entityColumn = "boardId")
     public List<Stack> stacks;
 
+    @Ignore
+    public List<User> users;
 
     public User getOwner() {
         return owner;
@@ -54,9 +57,17 @@ public class FullBoard implements IRemoteEntity {
         this.labels = labels;
     }
 
+    public List<User> getUsers() {
+        return users;
+    }
+
+    public void setUsers(List<User> users) {
+        this.users = users;
+    }
+
     @Ignore
     @Override
-    public IRemoteEntity getEntity() {
+    public Board getEntity() {
         return board;
     }
 
@@ -102,6 +113,7 @@ public class FullBoard implements IRemoteEntity {
         return result;
     }
 
+    @NonNull
     @Override
     public String toString() {
         return "FullBoard{" +
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullCard.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullCard.java
index 41303cac6..611baf3df 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullCard.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullCard.java
@@ -6,8 +6,6 @@ import androidx.room.Ignore;
 import androidx.room.Junction;
 import androidx.room.Relation;
 
-import org.jetbrains.annotations.NotNull;
-
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -25,7 +23,7 @@ import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 public class FullCard implements IRemoteEntity, DragAndDropModel {
 
     @Ignore
-    private transient boolean isAttachmentsSorted = false;
+    protected transient boolean isAttachmentsSorted = false;
 
     @Embedded
     public Card card;
@@ -48,7 +46,6 @@ public class FullCard implements IRemoteEntity, DragAndDropModel {
     @Relation(entity = DeckComment.class, parentColumn = "localId", entityColumn = "objectId", projection = "localId")
     public List<Long> commentIDs;
 
-
     public FullCard() {
         super();
     }
@@ -126,11 +123,11 @@ public class FullCard implements IRemoteEntity, DragAndDropModel {
 
     @Ignore
     @Override
-    public IRemoteEntity getEntity() {
+    public Card getEntity() {
         return card;
     }
 
-    @NotNull
+    @NonNull
     @Override
     public String toString() {
         return "FullCard{" +
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullCardWithProjects.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullCardWithProjects.java
new file mode 100644
index 000000000..cf43fc86b
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullCardWithProjects.java
@@ -0,0 +1,82 @@
+package it.niedermann.nextcloud.deck.model.full;
+
+import androidx.annotation.NonNull;
+import androidx.room.Junction;
+import androidx.room.Relation;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.ocs.projects.JoinCardWithProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.full.OcsProjectWithResources;
+
+public class FullCardWithProjects extends FullCard {
+
+
+    @NonNull
+    @Relation(entity = OcsProject.class, parentColumn = "localId", entityColumn = "localId",
+            associateBy = @Junction(value = JoinCardWithProject.class, parentColumn = "cardId", entityColumn = "projectId"))
+
+    private List<OcsProjectWithResources> projects = new ArrayList<>();
+
+    public FullCardWithProjects() {
+        super();
+    }
+
+    public FullCardWithProjects(FullCardWithProjects fullCard) {
+        super(fullCard);
+        this.projects = copyList(fullCard.getProjects());
+    }
+
+    @NonNull
+    public List<OcsProjectWithResources> getProjects() {
+        return projects;
+    }
+
+    public void setProjects(@NonNull List<OcsProjectWithResources> projects) {
+        this.projects = projects;
+    }
+
+    @NonNull
+    @Override
+    public String toString() {
+        return "FullCard{" +
+                "card=" + card +
+                ", labels=" + labels +
+                ", assignedUsers=" + assignedUsers +
+                ", owner=" + owner +
+                ", attachments=" + attachments +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        FullCardWithProjects fullCard = (FullCardWithProjects) o;
+
+        if (card != null ? !card.equals(fullCard.card) : fullCard.card != null) return false;
+        if (labels != null ? !labels.equals(fullCard.labels) : fullCard.labels != null)
+            return false;
+        if (assignedUsers != null ? !assignedUsers.equals(fullCard.assignedUsers) : fullCard.assignedUsers != null)
+            return false;
+        if (owner != null ? !owner.equals(fullCard.owner) : fullCard.owner != null) return false;
+        if (attachments != null ? !attachments.equals(fullCard.attachments) : fullCard.attachments != null)
+            return false;
+        return commentIDs != null ? commentIDs.equals(fullCard.commentIDs) : fullCard.commentIDs == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = (isAttachmentsSorted ? 1 : 0);
+        result = 31 * result + (card != null ? card.hashCode() : 0);
+        result = 31 * result + (labels != null ? labels.hashCode() : 0);
+        result = 31 * result + (assignedUsers != null ? assignedUsers.hashCode() : 0);
+        result = 31 * result + (owner != null ? owner.hashCode() : 0);
+        result = 31 * result + (attachments != null ? attachments.hashCode() : 0);
+        result = 31 * result + (commentIDs != null ? commentIDs.hashCode() : 0);
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullStack.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullStack.java
index eddbafce4..1c9e94899 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullStack.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/full/FullStack.java
@@ -14,7 +14,7 @@ public class FullStack implements IRemoteEntity {
     @Embedded
     public Stack stack;
 
-    @Relation(entity =  Card.class, parentColumn = "localId", entityColumn = "stackId")
+    @Relation(entity = Card.class, parentColumn = "localId", entityColumn = "stackId")
     public List<Card> cards;
 
 
@@ -36,7 +36,7 @@ public class FullStack implements IRemoteEntity {
 
     @Ignore
     @Override
-    public IRemoteEntity getEntity() {
+    public Stack getEntity() {
         return stack;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractJoinEntity.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractJoinEntity.java
index 50057dfe4..ce14ac6be 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractJoinEntity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractJoinEntity.java
@@ -1,21 +1,20 @@
 package it.niedermann.nextcloud.deck.model.interfaces;
 
-import androidx.annotation.NonNull;
 import androidx.room.Entity;
 import androidx.room.Ignore;
+
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 
 @Entity()
 public abstract class AbstractJoinEntity {
 
-    @NonNull
     protected int status = DBStatus.UP_TO_DATE.getId();
 
     public int getStatus() {
         return status;
     }
 
-    public void setStatus(@NonNull int status) {
+    public void setStatus(int status) {
         this.status = status;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractRemoteEntity.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractRemoteEntity.java
index 328c642ae..2f7771383 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractRemoteEntity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/AbstractRemoteEntity.java
@@ -1,31 +1,30 @@
 package it.niedermann.nextcloud.deck.model.interfaces;
 
-import androidx.annotation.NonNull;
 import androidx.room.Entity;
 import androidx.room.ForeignKey;
 import androidx.room.Ignore;
 import androidx.room.Index;
 import androidx.room.PrimaryKey;
 
-import java.util.Date;
+import java.time.Instant;
 
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 
 @Entity(
-    indices = {
-        @Index("accountId"),
-        @Index("id"),
-        @Index("lastModifiedLocal"),
-        @Index(value = {"accountId", "id"}, unique = true)
-    },
-    foreignKeys = {
-        @ForeignKey(
-            entity = Account.class,
-            parentColumns = "id",
-            childColumns = "accountId", onDelete = ForeignKey.CASCADE
-        )
-    }
+        indices = {
+                @Index("accountId"),
+                @Index("id"),
+                @Index("lastModifiedLocal"),
+                @Index(value = {"accountId", "id"}, unique = true)
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = Account.class,
+                        parentColumns = "id",
+                        childColumns = "accountId", onDelete = ForeignKey.CASCADE
+                )
+        }
 )
 public abstract class AbstractRemoteEntity implements IRemoteEntity {
     @PrimaryKey(autoGenerate = true)
@@ -35,11 +34,12 @@ public abstract class AbstractRemoteEntity implements IRemoteEntity {
 
     protected Long id;
 
-    @NonNull
     protected int status = DBStatus.UP_TO_DATE.getId();
 
-    protected Date lastModified;
-    protected Date lastModifiedLocal;
+    protected Instant lastModified;
+    protected Instant lastModifiedLocal;
+
+    protected String etag;
 
     public AbstractRemoteEntity() {
     }
@@ -102,35 +102,30 @@ public abstract class AbstractRemoteEntity implements IRemoteEntity {
 
 
     @Override
-    public void setStatus(@NonNull int status) {
+    public void setStatus(int status) {
         this.status = status;
     }
 
-
     @Override
-    public Date getLastModified() {
+    public Instant getLastModified() {
         return this.lastModified;
     }
 
-
     @Override
-    public void setLastModified(Date lastModified) {
+    public void setLastModified(Instant lastModified) {
         this.lastModified = lastModified;
     }
 
-
     @Override
-    public Date getLastModifiedLocal() {
+    public Instant getLastModifiedLocal() {
         return this.lastModifiedLocal;
     }
 
-
     @Override
-    public void setLastModifiedLocal(Date lastModifiedLocal) {
+    public void setLastModifiedLocal(Instant lastModifiedLocal) {
         this.lastModifiedLocal = lastModifiedLocal;
     }
 
-
     @Ignore
     @Override
     public DBStatus getStatusEnum() {
@@ -144,6 +139,15 @@ public abstract class AbstractRemoteEntity implements IRemoteEntity {
         this.status = status.getId();
     }
 
+    @Override
+    public String getEtag() {
+        return etag;
+    }
+
+    @Override
+    public void setEtag(String etag) {
+        this.etag = etag;
+    }
 
     @Override
     public boolean equals(Object o) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/IRemoteEntity.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/IRemoteEntity.java
index 30a478808..f197c0d30 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/IRemoteEntity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/interfaces/IRemoteEntity.java
@@ -1,94 +1,87 @@
 package it.niedermann.nextcloud.deck.model.interfaces;
 
-import androidx.annotation.NonNull;
-
+import java.time.Instant;
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 
 public interface IRemoteEntity {
 
-    default IRemoteEntity getEntity() {return this;}
+    default IRemoteEntity getEntity() {
+        return this;
+    }
 
     default Long getLocalId() {
         return getEntity().getLocalId();
     }
 
-    
     default void setLocalId(Long localId) {
         getEntity().setLocalId(localId);
     }
 
-    
     default long getAccountId() {
         return getEntity().getAccountId();
     }
 
-    
     default void setAccountId(long accountId) {
         getEntity().setAccountId(accountId);
     }
 
-    
     default Long getId() {
         return getEntity().getId();
     }
 
-    
     default void setId(Long id) {
         getEntity().setId(id);
     }
 
-    
     default int getStatus() {
         return getEntity().getStatus();
     }
 
-    
-    default void setStatus(@NonNull int status) {
+    default void setStatus(int status) {
         getEntity().setStatus(status);
     }
 
-    
-    default Date getLastModified() {
+    default Instant getLastModified() {
         return getEntity().getLastModified();
     }
 
-    
-    default void setLastModified(Date lastModified) {
+    default void setLastModified(Instant lastModified) {
         getEntity().setLastModified(lastModified);
     }
 
-    
-    default Date getLastModifiedLocal() {
+    default Instant getLastModifiedLocal() {
         return getEntity().getLastModifiedLocal();
     }
 
-    
-    default void setLastModifiedLocal(Date lastModifiedLocal) {
+    default void setLastModifiedLocal(Instant lastModifiedLocal) {
         getEntity().setLastModifiedLocal(lastModifiedLocal);
     }
 
-    
     default DBStatus getStatusEnum() {
         return getEntity().getStatusEnum();
     }
 
-    
     default void setStatusEnum(DBStatus status) {
         getEntity().setStatusEnum(status);
     }
 
+    default String getEtag() {
+        return getEntity().getEtag();
+    }
+
+    default void setEtag(String etag) {
+        getEntity().setEtag(etag);
+    }
+
     default <T> List<T> copyList(List<T> listToCopy) {
         if (listToCopy == null) {
             return null;
         }
         List<T> list = new ArrayList<>(listToCopy.size());
-        for (T t : listToCopy) {
-            list.add(t);
-        }
+        list.addAll(listToCopy);
         return list;
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/internal/FilterInformation.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/internal/FilterInformation.java
index f3892dfa5..1b5f0879d 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/internal/FilterInformation.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/internal/FilterInformation.java
@@ -3,8 +3,6 @@ package it.niedermann.nextcloud.deck.model.internal;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
-import org.jetbrains.annotations.NotNull;
-
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
@@ -14,12 +12,21 @@ import it.niedermann.nextcloud.deck.model.User;
 import it.niedermann.nextcloud.deck.model.enums.EDueType;
 
 public class FilterInformation implements Serializable {
+
+    public enum EArchiveStatus{
+        ALL, ARCHIVED, NON_ARCHIVED
+    }
+
     @NonNull
     private EDueType dueType = EDueType.NO_FILTER;
+    private boolean noAssignedLabel = false;
+    private boolean noAssignedUser = false;
     @NonNull
     private List<User> users = new ArrayList<>();
     @NonNull
     private List<Label> labels = new ArrayList<>();
+    @NonNull
+    private EArchiveStatus archiveStatus = EArchiveStatus.NON_ARCHIVED;
 
     public FilterInformation() {
         // Default constructor
@@ -28,8 +35,12 @@ public class FilterInformation implements Serializable {
     public FilterInformation(@Nullable FilterInformation filterInformation) {
         if (filterInformation != null) {
             this.dueType = filterInformation.getDueType();
+            this.archiveStatus = filterInformation.getArchiveStatus();
             this.users.addAll(filterInformation.getUsers());
             this.labels.addAll(filterInformation.getLabels());
+            this.noAssignedUser = filterInformation.isNoAssignedUser();
+            this.noAssignedLabel = filterInformation.isNoAssignedLabel();
+            this.archiveStatus = filterInformation.getArchiveStatus();
         }
     }
 
@@ -47,7 +58,7 @@ public class FilterInformation implements Serializable {
         return users;
     }
 
-    @NotNull
+    @NonNull
     public List<Label> getLabels() {
         return labels;
     }
@@ -68,23 +79,55 @@ public class FilterInformation implements Serializable {
         users.remove(user);
     }
 
-    @NotNull
+    public boolean isNoAssignedUser() {
+        return noAssignedUser;
+    }
+
+    public void setNoAssignedUser(boolean noAssignedUser) {
+        this.noAssignedUser = noAssignedUser;
+    }
+
+    public boolean isNoAssignedLabel() {
+        return noAssignedLabel;
+    }
+
+    public void setNoAssignedLabel(boolean noAssignedLabel) {
+        this.noAssignedLabel = noAssignedLabel;
+    }
+
+    public void setArchiveStatus(@NonNull EArchiveStatus archiveStatus) {
+        this.archiveStatus = archiveStatus;
+    }
+
+    @NonNull
+    public EArchiveStatus getArchiveStatus() {
+        return archiveStatus;
+    }
+
+    @NonNull
     @Override
     public String toString() {
         return "FilterInformation{" +
                 "dueType=" + dueType +
+                ", noAssignedLabel=" + noAssignedLabel +
+                ", noAssignedUser=" + noAssignedUser +
                 ", users=" + users +
                 ", labels=" + labels +
+                ", archiveStatus=" + archiveStatus +
                 '}';
     }
 
     /**
-     * @return whether or not the given filterInformation has any actual filters set
+     * @return whether or not the given {@param filterInformation} has any actual filters set
      */
     public static boolean hasActiveFilter(@Nullable FilterInformation filterInformation) {
         if (filterInformation == null) {
             return false;
         }
-        return filterInformation.getDueType() != EDueType.NO_FILTER || filterInformation.getUsers().size() > 0 || filterInformation.getLabels().size() > 0;
+        return filterInformation.getDueType() != EDueType.NO_FILTER
+                || filterInformation.getUsers().size() > 0
+                || filterInformation.getLabels().size() > 0
+                || filterInformation.noAssignedUser
+                || filterInformation.noAssignedLabel;
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/Capabilities.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/Capabilities.java
index 9ff4d7945..12e8692d4 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/Capabilities.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/Capabilities.java
@@ -5,8 +5,8 @@ public class Capabilities {
     private Version deckVersion;
     private Version nextcloudVersion;
 
-    private String color = "#0082c9";
-    private String textColor = "#ffffff";
+    private int color = 0;
+    private int textColor = 0;
     private boolean maintenanceEnabled = false;
 
     public Capabilities() {
@@ -28,19 +28,19 @@ public class Capabilities {
         this.nextcloudVersion = nextcloudVersion;
     }
 
-    public String getColor() {
+    public int getColor() {
         return color;
     }
 
-    public void setColor(String color) {
+    public void setColor(int color) {
         this.color = color;
     }
 
-    public String getTextColor() {
+    public int getTextColor() {
         return textColor;
     }
 
-    public void setTextColor(String textColor) {
+    public void setTextColor(int textColor) {
         this.textColor = textColor;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/Version.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/Version.java
index 7ef97a294..cfd973831 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/Version.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/Version.java
@@ -6,18 +6,18 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
 
-import org.jetbrains.annotations.NotNull;
-
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Attachment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 
 public class Version implements Comparable<Version> {
     private static final Pattern NUMBER_EXTRACTION_PATTERN = Pattern.compile("[0-9]+");
     private static final Version VERSION_1_0_0 = new Version("1.0.0", 1, 0, 0);
     private static final Version VERSION_1_0_3 = new Version("1.0.3", 1, 0, 3);
+    private static final Version VERSION_1_3_0 = new Version("1.3.0", 1, 3, 0);
     @Nullable
     private static Version VERSION_MINIMUM_SUPPORTED;
 
@@ -125,7 +125,7 @@ public class Version implements Comparable<Version> {
         return 0;
     }
 
-    @NotNull
+    @NonNull
     @Override
     public String toString() {
         return "Version{" +
@@ -157,6 +157,22 @@ public class Version implements Comparable<Version> {
     }
 
     /**
+     * Before {@link #VERSION_1_3_0} all {@link Attachment}s have been stored in a special folder at the server.
+     * Starting with {@link #VERSION_1_3_0} {@link Attachment}s can be stored as regular files, allowing for example to make use of server side thumbnail generation.
+     * <p>
+     * Since the migration takes a long time, it does not happen on upgrading the server app but step by step via a cronjob.
+     * Therefore this method is just an indicator, that it is possible that {@link Attachment}s are stored as files, but it is no guarantee that all {@link Attachment}s already have been migrated to files.
+     *
+     * @return whether or not the server supports file attachments
+     * @see <a href="https://github.com/nextcloud/deck/pull/2638">documentation in PR</a>
+     */
+    public boolean supportsFileAttachments() {
+        return false;
+//         TODO depends on https://github.com/nextcloud/deck/pull/2638
+//         return isGreaterOrEqualTo(VERSION_1_3_0);
+    }
+
+    /**
      * Title max length has been increased from 100 to 255 characters beginning with server {@link Version} 1.0.0
      *
      * @return the number of characters that the title fields of cards allow
@@ -167,6 +183,7 @@ public class Version implements Comparable<Version> {
                 ? 255
                 : 100;
     }
+
     /**
      * URL to view a card in the web interface has been changed in {@link Version} 1.0.0
      *
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/comment/DeckComment.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/comment/DeckComment.java
index 707bae974..8bba9740b 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/comment/DeckComment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/comment/DeckComment.java
@@ -5,12 +5,13 @@ import androidx.room.ForeignKey;
 import androidx.room.Ignore;
 import androidx.room.Index;
 
+import java.time.Instant;
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.model.Card;
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
+
 @Entity(inheritSuperIndices = true,
         indices = {
                 @Index(value = "accountId", name = "comment_accID"),
@@ -35,7 +36,7 @@ public class DeckComment extends AbstractRemoteEntity {
 
     private Long objectId;
     private String actorType;
-    private Date creationDateTime;
+    private Instant creationDateTime;
     private String actorId;
     private String actorDisplayName;
     private String message;
@@ -47,7 +48,7 @@ public class DeckComment extends AbstractRemoteEntity {
     }
 
     @Ignore
-    public DeckComment(String message, String actorDisplayName, Date creationDateTime) {
+    public DeckComment(String message, String actorDisplayName, Instant creationDateTime) {
         setMessage(message);
         setActorDisplayName(actorDisplayName);
         setCreationDateTime(creationDateTime);
@@ -76,11 +77,11 @@ public class DeckComment extends AbstractRemoteEntity {
         this.actorType = actorType;
     }
 
-    public Date getCreationDateTime() {
+    public Instant getCreationDateTime() {
         return creationDateTime;
     }
 
-    public void setCreationDateTime(Date creationDateTime) {
+    public void setCreationDateTime(Instant creationDateTime) {
         this.creationDateTime = creationDateTime;
     }
 
@@ -121,8 +122,8 @@ public class DeckComment extends AbstractRemoteEntity {
     }
 
     public void setMessage(String message) {
-        if (message!= null && message.length() > MAX_MESSAGE_LENGTH) {
-            throw new IllegalArgumentException("The server won't accept messages longer than "+MAX_MESSAGE_LENGTH+" characters!");
+        if (message != null && message.length() > MAX_MESSAGE_LENGTH) {
+            throw new IllegalArgumentException("The server won't accept messages longer than " + MAX_MESSAGE_LENGTH + " characters!");
         }
         this.message = message;
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/JoinCardWithProject.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/JoinCardWithProject.java
new file mode 100644
index 000000000..615c7a2a2
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/JoinCardWithProject.java
@@ -0,0 +1,66 @@
+package it.niedermann.nextcloud.deck.model.ocs.projects;
+
+import androidx.annotation.NonNull;
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Index;
+
+import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.model.interfaces.AbstractJoinEntity;
+
+@Entity(
+        primaryKeys = {"projectId", "cardId"},
+        indices = {@Index("cardId"), @Index("projectId")},
+        foreignKeys = {
+            @ForeignKey(entity = OcsProject.class,
+                parentColumns = "localId",
+                childColumns = "projectId",
+                onDelete = ForeignKey.CASCADE
+            ),
+            @ForeignKey(entity = Card.class,
+                parentColumns = "localId",
+                childColumns = "cardId",
+                onDelete = ForeignKey.CASCADE
+            )
+        })
+public class JoinCardWithProject extends AbstractJoinEntity {
+    @NonNull
+    private Long projectId;
+    @NonNull
+    private Long cardId;
+
+    @NonNull
+    public Long getProjectId() {
+        return projectId;
+    }
+
+    public void setProjectId(@NonNull Long projectId) {
+        this.projectId = projectId;
+    }
+
+    public Long getCardId() {
+        return cardId;
+    }
+
+    public void setCardId(Long cardId) {
+        this.cardId = cardId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        JoinCardWithProject that = (JoinCardWithProject) o;
+
+        if (!projectId.equals(that.projectId)) return false;
+        return cardId.equals(that.cardId);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = projectId.hashCode();
+        result = 31 * result + cardId.hashCode();
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/OcsProject.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/OcsProject.java
new file mode 100644
index 000000000..49bc7296d
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/OcsProject.java
@@ -0,0 +1,45 @@
+package it.niedermann.nextcloud.deck.model.ocs.projects;
+
+import androidx.annotation.NonNull;
+import androidx.room.Entity;
+import androidx.room.Ignore;
+import androidx.room.Index;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
+
+@Entity(inheritSuperIndices = true,
+        indices = {
+                @Index(value = "accountId", name = "index_project_accID"),
+        },
+        foreignKeys = {
+        }
+)
+public class OcsProject extends AbstractRemoteEntity {
+    @NonNull
+    private String name;
+
+    @Ignore
+    @NonNull
+    private ArrayList<OcsProjectResource> resources = new ArrayList<>();
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @NonNull
+    public ArrayList<OcsProjectResource> getResources() {
+        return resources;
+    }
+
+    public void setResources(@NonNull List<OcsProjectResource> resources) {
+        this.resources.clear();
+        this.resources.addAll(resources);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/OcsProjectList.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/OcsProjectList.java
new file mode 100644
index 000000000..af42b8432
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/OcsProjectList.java
@@ -0,0 +1,24 @@
+package it.niedermann.nextcloud.deck.model.ocs.projects;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class OcsProjectList {
+    List<OcsProject>  projects;
+
+    public OcsProjectList() {
+        projects = new ArrayList<>();
+    }
+
+    public OcsProjectList(List<OcsProject> projects) {
+        this.projects = projects;
+    }
+
+    public List<OcsProject> getProjects() {
+        return projects;
+    }
+
+    public void add(OcsProject project) {
+        projects.add(project);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/OcsProjectResource.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/OcsProjectResource.java
new file mode 100644
index 000000000..cd63ccde4
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/OcsProjectResource.java
@@ -0,0 +1,135 @@
+package it.niedermann.nextcloud.deck.model.ocs.projects;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Index;
+import androidx.room.RoomWarnings;
+
+import java.io.Serializable;
+
+import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
+
+@SuppressWarnings(RoomWarnings.INDEX_FROM_PARENT_IS_DROPPED)
+@Entity(
+        indices = {
+                @Index(value = "id", name = "index_OcsProjectResource_id"),
+                @Index(value = "lastModifiedLocal", name = "index_OcsProjectResource_lastModifiedLocal"),
+                @Index(value = {"accountId", "id", "idString", "projectId"}, name = "index_OcsProjectResource_accountId_id", unique = true),
+                @Index(value = "accountId", name = "index_projectResource_accID"),
+                @Index(value = "projectId", name = "index_projectResource_projectId"),
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = OcsProject.class,
+                        parentColumns = "localId",
+                        childColumns = "projectId", onDelete = ForeignKey.CASCADE
+                )
+        }
+)
+public class OcsProjectResource extends AbstractRemoteEntity implements Serializable {
+    @Nullable
+    private String type;
+    @Nullable
+    private String name;
+    @Nullable
+    private String link;
+    @Nullable
+    private String path;
+    @Nullable
+    private String iconUrl;
+    @Nullable
+    private String mimetype;
+    @Nullable
+    private Boolean previewAvailable;
+    @Nullable
+    private String idString;
+
+
+    @NonNull
+    private Long projectId;
+
+    public Long getProjectId() {
+        return projectId;
+    }
+
+    public void setProjectId(Long projectId) {
+        this.projectId = projectId;
+    }
+
+    @Nullable
+    public String getType() {
+        return type;
+    }
+
+    public void setType(@Nullable String type) {
+        this.type = type;
+    }
+
+    @Nullable
+    public String getName() {
+        return name;
+    }
+
+    public void setName(@Nullable String name) {
+        this.name = name;
+    }
+
+    /**
+     * Caution: the Link might be a full url or only the relative path!
+     * @return The link to the Resource
+     */
+    @Nullable
+    public String getLink() {
+        return link;
+    }
+
+    public void setLink(@Nullable String link) {
+        this.link = link;
+    }
+
+    @Nullable
+    public String getIconUrl() {
+        return iconUrl;
+    }
+
+    public void setIconUrl(@Nullable String iconUrl) {
+        this.iconUrl = iconUrl;
+    }
+
+    @Nullable
+    public String getPath() {
+        return path;
+    }
+
+    public void setPath(@Nullable String path) {
+        this.path = path;
+    }
+
+    @Nullable
+    public String getMimetype() {
+        return mimetype;
+    }
+
+    public void setMimetype(@Nullable String mimetype) {
+        this.mimetype = mimetype;
+    }
+
+    public Boolean getPreviewAvailable() {
+        return Boolean.TRUE.equals(previewAvailable);
+    }
+
+    public void setPreviewAvailable(@Nullable Boolean previewAvailable) {
+        this.previewAvailable = previewAvailable;
+    }
+
+    @Nullable
+    public String getIdString() {
+        return idString;
+    }
+
+    public void setIdString(@Nullable String idString) {
+        this.idString = idString;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/full/OcsProjectWithResources.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/full/OcsProjectWithResources.java
new file mode 100644
index 000000000..257cf6f60
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/projects/full/OcsProjectWithResources.java
@@ -0,0 +1,50 @@
+package it.niedermann.nextcloud.deck.model.ocs.projects.full;
+
+import androidx.annotation.NonNull;
+import androidx.room.Embedded;
+import androidx.room.Relation;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.interfaces.IRemoteEntity;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+
+public class OcsProjectWithResources implements IRemoteEntity {
+    @Embedded
+    public OcsProject project;
+
+
+    @Relation(entity = OcsProjectResource.class, parentColumn = "localId", entityColumn = "projectId")
+    public List<OcsProjectResource> resources;
+
+    public OcsProject getProject() {
+        return project;
+    }
+
+    public void setProject(OcsProject project) {
+        this.project = project;
+    }
+
+    @NonNull
+    public List<OcsProjectResource> getResources() {
+        return resources;
+    }
+
+    public void setResources(List<OcsProjectResource> resources) {
+        this.resources = resources;
+    }
+
+    public String getName() {
+        return project.getName();
+    }
+
+    public void setName(String name) {
+        project.setName(name);
+    }
+
+    @Override
+    public IRemoteEntity getEntity() {
+        return project;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/user/GroupMemberUIDs.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/user/GroupMemberUIDs.java
new file mode 100644
index 000000000..085ca786e
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/user/GroupMemberUIDs.java
@@ -0,0 +1,27 @@
+package it.niedermann.nextcloud.deck.model.ocs.user;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class GroupMemberUIDs {
+    private List<String> uids = new ArrayList<>();
+
+    public List<String> getUids() {
+        return uids;
+    }
+
+    public void setUids(List<String> uids) {
+        this.uids = uids;
+    }
+
+    @Override
+    public String toString() {
+        return "GroupMemberUIDs{" +
+                "uids=" + uids +
+                '}';
+    }
+
+    public void add(String uid) {
+        uids.add(uid);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/user/OcsUserList.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/user/OcsUserList.java
index a10ae005d..818d5b96e 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/user/OcsUserList.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/ocs/user/OcsUserList.java
@@ -1,7 +1,16 @@
 package it.niedermann.nextcloud.deck.model.ocs.user;
 
 import java.util.ArrayList;
+import java.util.List;
 
-public class OcsUserList extends ArrayList<String> {
-    // nothing.
+public class OcsUserList {
+    private List<OcsUser> users = new ArrayList<>();
+
+    public List<OcsUser> getUsers() {
+        return users;
+    }
+
+    public void addUser(OcsUser user) {
+        this.users.add(user);
+    }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/relations/UserInBoard.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/relations/UserInBoard.java
new file mode 100644
index 000000000..1f167bad1
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/relations/UserInBoard.java
@@ -0,0 +1,71 @@
+package it.niedermann.nextcloud.deck.model.relations;
+
+import androidx.annotation.NonNull;
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Index;
+
+import it.niedermann.nextcloud.deck.model.Board;
+import it.niedermann.nextcloud.deck.model.User;
+
+@Entity(
+        primaryKeys = {"userId", "boardId"},
+        indices = {@Index("userId"), @Index("boardId"), @Index(name = "unique_idx_user_board", value = {"userId","boardId"}, unique = true)},
+        foreignKeys = {
+                @ForeignKey(entity = User.class,
+                        parentColumns = "localId",
+                        childColumns = "userId", onDelete = ForeignKey.CASCADE),
+                @ForeignKey(entity = Board.class,
+                        parentColumns = "localId",
+                        childColumns = "boardId", onDelete = ForeignKey.CASCADE)
+        })
+public class UserInBoard {
+    @NonNull
+    private Long userId;
+    @NonNull
+    private Long boardId;
+
+    @NonNull
+    public Long getUserId() {
+        return userId;
+    }
+
+    public void setUserId(@NonNull Long userId) {
+        this.userId = userId;
+    }
+
+    @NonNull
+    public Long getBoardId() {
+        return boardId;
+    }
+
+    public void setBoardId(@NonNull Long boardId) {
+        this.boardId = boardId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        UserInBoard that = (UserInBoard) o;
+
+        if (!userId.equals(that.userId)) return false;
+        return boardId.equals(that.boardId);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = userId.hashCode();
+        result = 31 * result + boardId.hashCode();
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "UserInGroup{" +
+                "userId=" + userId +
+                ", boardId=" + boardId +
+                '}';
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/relations/UserInGroup.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/relations/UserInGroup.java
new file mode 100644
index 000000000..48e16cce5
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/relations/UserInGroup.java
@@ -0,0 +1,70 @@
+package it.niedermann.nextcloud.deck.model.relations;
+
+import androidx.annotation.NonNull;
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Index;
+
+import it.niedermann.nextcloud.deck.model.User;
+
+@Entity(
+        primaryKeys = {"groupId", "memberId"},
+        indices = {@Index("groupId"), @Index("memberId"), @Index(name = "unique_idx_group_member", value = {"groupId","memberId"}, unique = true)},
+        foreignKeys = {
+                @ForeignKey(entity = User.class,
+                        parentColumns = "localId",
+                        childColumns = "groupId", onDelete = ForeignKey.CASCADE),
+                @ForeignKey(entity = User.class,
+                        parentColumns = "localId",
+                        childColumns = "memberId", onDelete = ForeignKey.CASCADE)
+        })
+public class UserInGroup {
+    @NonNull
+    private Long groupId;
+    @NonNull
+    private Long memberId;
+
+    @NonNull
+    public Long getGroupId() {
+        return groupId;
+    }
+
+    public void setGroupId(@NonNull Long groupId) {
+        this.groupId = groupId;
+    }
+
+    @NonNull
+    public Long getMemberId() {
+        return memberId;
+    }
+
+    public void setMemberId(@NonNull Long memberId) {
+        this.memberId = memberId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        UserInGroup that = (UserInGroup) o;
+
+        if (!groupId.equals(that.groupId)) return false;
+        return memberId.equals(that.memberId);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = groupId.hashCode();
+        result = 31 * result + memberId.hashCode();
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "UserInGroup{" +
+                "groupId=" + groupId +
+                ", memberId=" + memberId +
+                '}';
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncManager.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncManager.java
index 9ed9035cf..d93835423 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncManager.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncManager.java
@@ -1,31 +1,43 @@
 package it.niedermann.nextcloud.deck.persistence.sync;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
 import android.database.sqlite.SQLiteConstraintException;
 
 import androidx.annotation.AnyThread;
+import androidx.annotation.ColorInt;
+import androidx.annotation.MainThread;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.Size;
 import androidx.annotation.WorkerThread;
 import androidx.core.util.Pair;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MediatorLiveData;
 import androidx.lifecycle.MutableLiveData;
 
+import com.nextcloud.android.sso.api.ParsedResponse;
 import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
 
 import java.io.File;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Date;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.GsonConfig;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.api.LastSyncUtil;
+import it.niedermann.nextcloud.deck.exceptions.DeckException;
 import it.niedermann.nextcloud.deck.exceptions.OfflineException;
 import it.niedermann.nextcloud.deck.model.AccessControl;
 import it.niedermann.nextcloud.deck.model.Account;
@@ -36,9 +48,11 @@ import it.niedermann.nextcloud.deck.model.JoinCardWithUser;
 import it.niedermann.nextcloud.deck.model.Label;
 import it.niedermann.nextcloud.deck.model.Stack;
 import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.model.appwidgets.StackWidgetModel;
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.model.full.FullCardWithProjects;
 import it.niedermann.nextcloud.deck.model.full.FullSingleCardWidgetModel;
 import it.niedermann.nextcloud.deck.model.full.FullStack;
 import it.niedermann.nextcloud.deck.model.internal.FilterInformation;
@@ -46,12 +60,12 @@ import it.niedermann.nextcloud.deck.model.ocs.Capabilities;
 import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.OcsComment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.full.FullDeckComment;
-import it.niedermann.nextcloud.deck.model.ocs.user.OcsUser;
-import it.niedermann.nextcloud.deck.model.ocs.user.OcsUserList;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.extrawurst.UserSearchLiveData;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.DataPropagationHelper;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.AbstractSyncDataProvider;
@@ -64,20 +78,23 @@ import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.CardPropa
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.DeckCommentsDataProvider;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.LabelDataProvider;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.StackDataProvider;
-import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.partial.BoardWitAclDownSyncDataProvider;
-import it.niedermann.nextcloud.deck.util.DateUtil;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.partial.BoardWithAclDownSyncDataProvider;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.partial.BoardWithStacksAndLabelsUpSyncDataProvider;
 
+import static java.net.HttpURLConnection.HTTP_NOT_MODIFIED;
 import static java.net.HttpURLConnection.HTTP_UNAVAILABLE;
 
 @SuppressWarnings("WeakerAccess")
 public class SyncManager {
 
     @NonNull
-    private Context appContext;
+    private final Context appContext;
     @NonNull
-    private DataBaseAdapter dataBaseAdapter;
+    private final DataBaseAdapter dataBaseAdapter;
     @NonNull
-    private ServerAdapter serverAdapter;
+    private final ServerAdapter serverAdapter;
+
+    private static final Map<Long, List<IResponseCallback<Boolean>>> RUNNING_SYNCS = new ConcurrentHashMap<>();
 
     @AnyThread
     public SyncManager(@NonNull Context context) {
@@ -98,62 +115,35 @@ public class SyncManager {
     }
 
     @AnyThread
-    public MutableLiveData<FullCard> synchronizeCardByRemoteId(long cardRemoteId, @NonNull Account account) {
-        MutableLiveData<FullCard> liveData = new MutableLiveData<>();
-        doAsync(() -> {
-            Long accountId = account.getId();
-            Card card = dataBaseAdapter.getCardByRemoteIdDirectly(accountId, cardRemoteId);
-            FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getStackId());
-            // only sync this one card.
-            stack.setCards(Collections.singletonList(card));
-            Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
-            new SyncHelper(serverAdapter, dataBaseAdapter, new Date()).setResponseCallback(new IResponseCallback<Boolean>(account) {
-                @Override
-                public void onResponse(Boolean response) {
-                    FullCard fullCard = dataBaseAdapter.getFullCardByLocalIdDirectly(accountId, card.getLocalId());
-                    liveData.postValue(fullCard);
-                }
-
-                @Override
-                public void onError(Throwable throwable) {
-                    liveData.postValue(null);
-                }
-            }).doSyncFor(new CardDataProvider(null, board, stack));
-        });
-        return liveData;
-    }
-
-    // TODO if the card does not exist yet, try to synchronize it first, instead of directly returning null. If sync failed, return null.
-    @AnyThread
     public LiveData<Long> getLocalBoardIdByCardRemoteIdAndAccount(long cardRemoteId, @NonNull Account account) {
         return dataBaseAdapter.getLocalBoardIdByCardRemoteIdAndAccountId(cardRemoteId, account.getId());
     }
 
-    @AnyThread
+    @WorkerThread
     public boolean synchronizeEverything() {
         List<Account> accounts = dataBaseAdapter.getAllAccountsDirectly();
         if (accounts.size() > 0) {
-            final BooleanResultHolder success = new BooleanResultHolder();
+            final AtomicBoolean success = new AtomicBoolean();
             CountDownLatch latch = new CountDownLatch(accounts.size());
             try {
                 for (Account account : accounts) {
                     new SyncManager(dataBaseAdapter.getContext(), account.getName()).synchronize(new IResponseCallback<Boolean>(account) {
                         @Override
                         public void onResponse(Boolean response) {
-                            success.result = success.result && Boolean.TRUE.equals(response);
+                            success.set(success.get() && Boolean.TRUE.equals(response));
                             latch.countDown();
                         }
 
                         @Override
                         public void onError(Throwable throwable) {
-                            success.result = false;
+                            success.set(false);
                             super.onError(throwable);
                             latch.countDown();
                         }
                     });
                 }
                 latch.await();
-                return success.result;
+                return success.get();
             } catch (InterruptedException e) {
                 DeckLog.logError(e);
                 return false;
@@ -164,76 +154,160 @@ public class SyncManager {
 
     @AnyThread
     public void synchronize(@NonNull IResponseCallback<Boolean> responseCallback) {
-        if(responseCallback.getAccount() == null) {
+        synchronize(Collections.singletonList(responseCallback));
+    }
+
+    @AnyThread
+    public void synchronizeBoard(@NonNull IResponseCallback<Boolean> responseCallback, long localBoadId) {
+        doAsync(() -> {
+            FullBoard board = dataBaseAdapter.getFullBoardByLocalIdDirectly(responseCallback.getAccount().getId(), localBoadId);
+            try {
+                new SyncHelper(serverAdapter, dataBaseAdapter, null).setResponseCallback(responseCallback).doSyncFor(new StackDataProvider(null, board));
+            } catch (OfflineException e) {
+                responseCallback.onError(e);
+            }
+        });
+    }
+
+    @AnyThread
+    public void synchronizeCard(@NonNull IResponseCallback<Boolean> responseCallback, Card card) {
+        doAsync(() -> {
+            FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getStackId());
+            Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
+            try {
+                new SyncHelper(serverAdapter, dataBaseAdapter, null).setResponseCallback(responseCallback).doSyncFor(new CardDataProvider(null, board, stack));
+            } catch (OfflineException e) {
+                responseCallback.onError(e);
+            }
+        });
+    }
+
+    private void synchronize(@NonNull @Size(min = 1) List<IResponseCallback<Boolean>> responseCallbacks) {
+        if (responseCallbacks == null || responseCallbacks.size() < 1) {
+            return;
+        }
+        IResponseCallback<Boolean> responseCallback = responseCallbacks.get(0);
+        Account callbackAccount = responseCallback.getAccount();
+        if (callbackAccount == null) {
             throw new IllegalArgumentException(Account.class.getSimpleName() + " object in given " + IResponseCallback.class.getSimpleName() + " must not be null.");
         }
-        if(responseCallback.getAccount().getId() == null) {
+        Long callbackAccountId = callbackAccount.getId();
+        if (callbackAccountId == null) {
             throw new IllegalArgumentException(Account.class.getSimpleName() + " object in given " + IResponseCallback.class.getSimpleName() + " must contain a valid id, but given id was null.");
         }
-        doAsync(() -> refreshCapabilities(new IResponseCallback<Capabilities>(responseCallback.getAccount()) {
-            @Override
-            public void onResponse(Capabilities response) {
-                if (!response.isMaintenanceEnabled()) {
-                    if (response.getDeckVersion().isSupported(appContext)) {
-                        long accountId = responseCallback.getAccount().getId();
-                        Date lastSyncDate = LastSyncUtil.getLastSyncDate(responseCallback.getAccount().getId());
-                        Date now = DateUtil.nowInGMT();
-
-                        final SyncHelper syncHelper = new SyncHelper(serverAdapter, dataBaseAdapter, lastSyncDate);
+        List<IResponseCallback<Boolean>> queuedCallbacks = RUNNING_SYNCS.get(callbackAccountId);
+        if (queuedCallbacks != null) {
+            queuedCallbacks.addAll(responseCallbacks);
+            return;
+        } else {
+            RUNNING_SYNCS.put(callbackAccountId, new ArrayList<>(responseCallbacks));
+        }
+        doAsync(() -> {
+            List<IResponseCallback<Boolean>> existingQueue = RUNNING_SYNCS.get(callbackAccountId);
+            List<IResponseCallback<Boolean>> callbacksQueueForSync = existingQueue == null ? new ArrayList<>() : new ArrayList<>(existingQueue);
+            refreshCapabilities(new IResponseCallback<Capabilities>(responseCallback.getAccount()) {
+                @Override
+                public void onResponse(Capabilities response) {
+                    if (response != null && !response.isMaintenanceEnabled()) {
+                        if (response.getDeckVersion().isSupported(appContext)) {
+                            long accountId = callbackAccountId;
+                            Instant lastSyncDate = LastSyncUtil.getLastSyncDate(callbackAccountId);
 
-                        IResponseCallback<Boolean> callback = new IResponseCallback<Boolean>(responseCallback.getAccount()) {
-                            @Override
-                            public void onResponse(Boolean response) {
-                                syncHelper.setResponseCallback(new IResponseCallback<Boolean>(account) {
-                                    @Override
-                                    public void onResponse(Boolean response) {
-                                        // TODO deactivate for dev
-                                        LastSyncUtil.setLastSyncDate(accountId, now);
-                                        responseCallback.onResponse(response);
-                                    }
+                            final SyncHelper syncHelper = new SyncHelper(serverAdapter, dataBaseAdapter, lastSyncDate);
 
-                                    @Override
-                                    public void onError(Throwable throwable) {
-                                        super.onError(throwable);
-                                        responseCallback.onError(throwable);
-                                    }
-                                });
-                                doAsync(() -> {
-                                    try {
-                                        syncHelper.doUpSyncFor(new BoardDataProvider());
-                                    } catch (Throwable e) {
-                                        DeckLog.logError(e);
-                                        responseCallback.onError(e);
-                                    }
-                                });
+                            IResponseCallback<Boolean> callback = new IResponseCallback<Boolean>(callbackAccount) {
+                                @Override
+                                public void onResponse(Boolean response) {
+                                    syncHelper.setResponseCallback(new IResponseCallback<Boolean>(account) {
+                                        @Override
+                                        public void onResponse(Boolean response) {
+                                            // TODO deactivate for dev
+                                            LastSyncUtil.setLastSyncDate(accountId, Instant.now());
+                                            respondCallbacksAfterSync(callbacksQueueForSync, response, null);
+                                        }
+
+                                        @Override
+                                        public void onError(Throwable throwable) {
+                                            super.onError(throwable);
+                                            respondCallbacksAfterSync(callbacksQueueForSync, null, throwable);
+                                        }
+                                    });
+                                    doAsync(() -> {
+                                        try {
+                                            syncHelper.doUpSyncFor(new BoardDataProvider());
+                                        } catch (Throwable e) {
+                                            DeckLog.logError(e);
+                                            respondCallbacksAfterSync(callbacksQueueForSync, null, e);
+                                        }
+                                    });
 
-                            }
+                                }
 
-                            @Override
-                            public void onError(Throwable throwable) {
-                                super.onError(throwable);
-                                responseCallback.onError(throwable);
-                            }
-                        };
+                                @Override
+                                public void onError(Throwable throwable) {
+                                    super.onError(throwable);
+                                    respondCallbacksAfterSync(callbacksQueueForSync, null, throwable);
+                                }
+                            };
 
-                        syncHelper.setResponseCallback(callback);
+                            syncHelper.setResponseCallback(callback);
 
-                        try {
-                            syncHelper.doSyncFor(new BoardDataProvider());
-                        } catch (Throwable e) {
-                            DeckLog.logError(e);
-                            responseCallback.onError(e);
+                            try {
+                                syncHelper.doSyncFor(new BoardDataProvider());
+                            } catch (Throwable e) {
+                                DeckLog.logError(e);
+                                respondCallbacksAfterSync(callbacksQueueForSync, null, e);
+                            }
+                        } else {
+                            respondCallbacksAfterSync(callbacksQueueForSync, Boolean.FALSE, null);
+                            DeckLog.warn("No sync. Server version not supported: " + response.getDeckVersion().getOriginalVersion());
                         }
                     } else {
-                        responseCallback.onResponse(false);
-                        DeckLog.warn("No sync. Server version not supported: " + response.getDeckVersion().getOriginalVersion());
+                        respondCallbacksAfterSync(callbacksQueueForSync, Boolean.FALSE, null);
+                        if (response != null) {
+                            DeckLog.warn("No sync. Status maintenance mode: " + response.isMaintenanceEnabled());
+                        }
                     }
-                } else {
-                    responseCallback.onResponse(false);
-                    DeckLog.warn("No sync. Status maintenance mode: " + response.isMaintenanceEnabled());
                 }
+            });
+        });
+    }
+
+    private void respondCallbacksAfterSync(List<IResponseCallback<Boolean>> callbacksQueueForSync, Boolean response, Throwable throwable) {
+        if (callbacksQueueForSync == null || callbacksQueueForSync.isEmpty()) {
+            return;
+        }
+        // notify done callbacks
+        DeckLog.info("SyncQueue: responding sync for " + callbacksQueueForSync.size() + " queued callbacks!");
+        List<IResponseCallback<Boolean>> callbacksQueue = new ArrayList<>(callbacksQueueForSync);
+        if (throwable == null) {
+            //success:
+            for (IResponseCallback<Boolean> callback : callbacksQueue) {
+                if (callback != null) callback.onResponse(response);
             }
-        }));
+        } else {
+            // failure:
+            for (IResponseCallback<Boolean> callback : callbacksQueue) {
+                if (callback != null) callback.onError(throwable);
+            }
+        }
+        // remove done callbacks from queue
+        IResponseCallback<Boolean> firstCallbackOfAccount = callbacksQueue.iterator().next();
+        List<IResponseCallback<Boolean>> queuedCallbacks = RUNNING_SYNCS.get(firstCallbackOfAccount.getAccount().getId());
+        if (queuedCallbacks == null) {
+            return;
+        }
+        for (IResponseCallback<Boolean> callback : callbacksQueue) {
+            queuedCallbacks.remove(callback);
+        }
+        // cleanup if done, or proceed if not
+        if (queuedCallbacks.isEmpty()) {
+            RUNNING_SYNCS.remove(firstCallbackOfAccount.getAccount().getId());
+        } else {
+            DeckLog.info("SyncQueue: starting sync for " + queuedCallbacks.size() + " queued callbacks!");
+            RUNNING_SYNCS.remove(firstCallbackOfAccount.getAccount().getId());
+            synchronize(queuedCallbacks);
+        }
     }
 
 //
@@ -274,14 +348,15 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<Account> createAccount(@NonNull Account accout) {
-        return dataBaseAdapter.createAccount(accout);
+    public WrappedLiveData<Account> createAccount(@NonNull Account account) {
+        return dataBaseAdapter.createAccount(account);
     }
 
     public boolean hasInternetConnection() {
         return serverAdapter.hasInternetConnection();
     }
 
+    @AnyThread
     public void deleteAccount(long id) {
         doAsync(() -> {
             dataBaseAdapter.deleteAccount(id);
@@ -289,10 +364,6 @@ public class SyncManager {
         });
     }
 
-    public void updateAccount(Account account) {
-        dataBaseAdapter.updateAccount(account);
-    }
-
     @AnyThread
     public LiveData<Account> readAccount(long id) {
         return dataBaseAdapter.readAccount(id);
@@ -320,7 +391,7 @@ public class SyncManager {
      * - located at the given {@param host}
      * - and have the permission to read the board with the given {@param boardRemoteId} (aka the {@link Board} is shared with this {@link User}).
      */
-    @AnyThread
+    @MainThread
     public LiveData<List<Account>> readAccountsForHostWithReadAccessToBoard(String host, long boardRemoteId) {
         MediatorLiveData<List<Account>> liveData = new MediatorLiveData<>();
         liveData.addSource(dataBaseAdapter.readAccountsForHostWithReadAccessToBoard(host, boardRemoteId), accounts -> {
@@ -333,7 +404,7 @@ public class SyncManager {
                                 public void onResponse(Boolean response) {
                                     liveData.postValue(dataBaseAdapter.readAccountsForHostWithReadAccessToBoardDirectly(host, boardRemoteId));
                                 }
-                            }).doSyncFor(new BoardWitAclDownSyncDataProvider());
+                            }).doSyncFor(new BoardWithAclDownSyncDataProvider());
                 }
             });
         });
@@ -345,15 +416,17 @@ public class SyncManager {
     public void refreshCapabilities(@NonNull IResponseCallback<Capabilities> callback) {
         doAsync(() -> {
             try {
-                serverAdapter.getCapabilities(new IResponseCallback<Capabilities>(callback.getAccount()) {
+                Account accountForEtag = dataBaseAdapter.getAccountByIdDirectly(callback.getAccount().getId());
+                serverAdapter.getCapabilities(accountForEtag.getEtag(), new IResponseCallback<ParsedResponse<Capabilities>>(callback.getAccount()) {
                     @Override
-                    public void onResponse(Capabilities response) {
+                    public void onResponse(ParsedResponse<Capabilities> response) {
                         Account acc = dataBaseAdapter.getAccountByIdDirectly(account.getId());
-                        acc.applyCapabilities(response);
+                        acc.applyCapabilities(response.getResponse(), response.getHeaders().get("ETag"));
                         dataBaseAdapter.updateAccount(acc);
-                        callback.onResponse(response);
+                        callback.onResponse(response.getResponse());
                     }
 
+                    @SuppressLint("MissingSuperCall")
                     @Override
                     public void onError(Throwable throwable) {
                         if (throwable instanceof NextcloudHttpRequestFailedException) {
@@ -361,13 +434,28 @@ public class SyncManager {
                             if (requestFailedException.getStatusCode() == HTTP_UNAVAILABLE && requestFailedException.getCause() != null) {
                                 String errorString = requestFailedException.getCause().getMessage();
                                 Capabilities capabilities = GsonConfig.getGson().fromJson(errorString, Capabilities.class);
+                                DeckLog.verbose("HTTP Status " + HTTP_UNAVAILABLE + ": This server seems to be in maintenance mode.");
                                 if (capabilities.isMaintenanceEnabled()) {
-                                    doAsync(() -> {
-                                        onResponse(capabilities);
-                                    });
+                                    doAsync(() -> onResponse(ParsedResponse.of(capabilities)));
                                 } else {
                                     onError(throwable);
                                 }
+                            } else if (requestFailedException.getStatusCode() == HTTP_NOT_MODIFIED) {
+                                DeckLog.verbose("HTTP Status " + HTTP_NOT_MODIFIED + ": There haven't been any changes on the server side for this request.");
+                                //could be after maintenance. so we have to at least revert the maintenance flag
+                                doAsync(() -> {
+                                    Account acc = dataBaseAdapter.getAccountByIdDirectly(account.getId());
+                                    if (acc.isMaintenanceEnabled()) {
+                                        acc.setMaintenanceEnabled(false);
+                                        dataBaseAdapter.updateAccount(acc);
+                                    }
+                                    Capabilities capabilities = new Capabilities();
+                                    capabilities.setMaintenanceEnabled(false);
+                                    capabilities.setDeckVersion(acc.getServerDeckVersionAsObject());
+                                    capabilities.setTextColor(acc.getTextColor());
+                                    capabilities.setColor(acc.getColor());
+                                    callback.onResponse(capabilities);
+                                });
                             }
                         } else {
                             callback.onError(throwable);
@@ -377,39 +465,30 @@ public class SyncManager {
             } catch (OfflineException e) {
                 callback.onError(e);
             }
-
-            try {
-                serverAdapter.getAllOcsUsers(new IResponseCallback<OcsUserList>(callback.getAccount()) {
-                    @Override
-                    public void onResponse(OcsUserList response) {
-                        Long accountId = callback.getAccount().getId();
-                        for (String ocsUserName : response) {
-                            User existingUser = dataBaseAdapter.getUserByUidDirectly(accountId, ocsUserName);
-                            if (existingUser == null) {
-                                // we don't know this user, lets get some details...
-                                serverAdapter.getOcsUserDetails(ocsUserName, new IResponseCallback<OcsUser>(callback.getAccount()) {
-                                    @Override
-                                    public void onResponse(OcsUser response) {
-                                        User newUser = new User();
-                                        newUser.setStatus(DBStatus.UP_TO_DATE.getId());
-                                        newUser.setPrimaryKey(ocsUserName);
-                                        newUser.setUid(ocsUserName);
-                                        newUser.setDisplayname(response.getDisplayName());
-                                        dataBaseAdapter.createUser(accountId, newUser);
-                                    }
-                                });
-                            }
-                        }
-                    }
-                });
-            } catch (OfflineException ignored) {
-                // Nothing to do here...
-            }
         });
     }
 
     /**
      * @param accountId ID of the account
+     * @return all {@link Board}s no matter if {@link Board#archived} or not.
+     */
+    @SuppressWarnings("JavadocReference")
+    @AnyThread
+    public LiveData<List<Board>> getBoards(long accountId) {
+        return dataBaseAdapter.getBoards(accountId);
+    }
+
+    /**
+     * @param localProjectId LocalId of the OcsProject
+     * @return all {@link OcsProjectResource}s of the Project
+     */
+    @AnyThread
+    public LiveData<List<OcsProjectResource>> getResourcesForProject(long localProjectId) {
+        return dataBaseAdapter.getResourcesByLocalProjectId(localProjectId);
+    }
+
+    /**
+     * @param accountId ID of the account
      * @param archived  Decides whether only archived or not-archived boards for the specified account will be returned
      * @return all archived or non-archived <code>Board</code>s depending on <code>archived</code> parameter
      */
@@ -445,8 +524,8 @@ public class SyncManager {
     }
 
     @AnyThread
-    public LiveData<FullBoard> createBoard(long accountId, @NonNull Board board) {
-        MutableLiveData<FullBoard> liveData = new MutableLiveData<>();
+    public WrappedLiveData<FullBoard> createBoard(long accountId, @NonNull Board board) {
+        WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             User owner = dataBaseAdapter.getUserByUidDirectly(accountId, account.getUserName());
@@ -465,6 +544,12 @@ public class SyncManager {
                     public void onResponse(FullBoard response) {
                         liveData.postValue(response);
                     }
+
+                    @SuppressLint("MissingSuperCall")
+                    @Override
+                    public void onError(Throwable throwable, FullBoard entity) {
+                        liveData.postError(throwable, entity);
+                    }
                 });
             }
         });
@@ -474,58 +559,145 @@ public class SyncManager {
     /**
      * Creates a new {@link Board} and adds the same {@link Label} and {@link Stack} as in the origin {@link Board}.
      * Owner of the target {@link Board} will be the {@link User} with the {@link Account} of {@param targetAccountId}.
-     * Does <strong>not</strong> clone any {@link Card} or {@link AccessControl} from the origin {@link Board}.
+     *
+     * @param cloneCards determines whether or not the cards in this {@link Board} shall be cloned or not
+     *                   Does <strong>not</strong> clone any {@link Card} or {@link AccessControl} from the origin {@link Board}.
+     *                   <p>
+     *                   TODO implement https://github.com/stefan-niedermann/nextcloud-deck/issues/608
      */
     @AnyThread
-    public WrappedLiveData<FullBoard> cloneBoard(long originAccountId, long originBoardLocalId, long targetAccountId, String targetBoardTitle, String targetBoardColor) {
-        WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
+    public WrappedLiveData<FullBoard> cloneBoard(long originAccountId, long originBoardLocalId, long targetAccountId, @ColorInt int targetBoardColor, boolean cloneCards) {
+        final WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
 
         doAsync(() -> {
             Account originAccount = dataBaseAdapter.getAccountByIdDirectly(originAccountId);
             User newOwner = dataBaseAdapter.getUserByUidDirectly(originAccountId, originAccount.getUserName());
+            if (newOwner == null) {
+                liveData.postError(new DeckException(DeckException.Hint.UNKNOWN_ACCOUNT_USER_ID, "User with Account-UID \"" + originAccount.getUserName() + "\" not found."));
+                return;
+            }
             FullBoard originalBoard = dataBaseAdapter.getFullBoardByLocalIdDirectly(originAccountId, originBoardLocalId);
+            String newBoardTitleBaseName = originalBoard.getBoard().getTitle().trim();
+            int newBoardTitleCopyIndex = 0;
+            //already a copy?
+            String regex = " \\(copy [0-9]+\\)$";
+            Pattern pattern = Pattern.compile(regex);
+            Matcher matcher = pattern.matcher(originalBoard.getBoard().getTitle());
+            if (matcher.find()) {
+                String found = matcher.group();
+                newBoardTitleBaseName = newBoardTitleBaseName.substring(0, newBoardTitleBaseName.length() - found.length());
+                Matcher indexMatcher = Pattern.compile("[0-9]+").matcher(found);
+                //noinspection ResultOfMethodCallIgnored
+                indexMatcher.find();
+                String oldIndexString = indexMatcher.group();
+                newBoardTitleCopyIndex = Integer.parseInt(oldIndexString);
+            }
+
+            String newBoardTitle;
+            do {
+                newBoardTitleCopyIndex++;
+                newBoardTitle = newBoardTitleBaseName + " (copy " + newBoardTitleCopyIndex + ")";
+
+            } while (dataBaseAdapter.getBoardForAccountByNameDirectly(targetAccountId, newBoardTitle) != null);
+
+
             originalBoard.setAccountId(targetAccountId);
-            originalBoard.getBoard().setTitle(targetBoardTitle);
-            originalBoard.getBoard().setColor(targetBoardColor);
-            originalBoard.getBoard().setOwnerId(newOwner.getId());
-            originalBoard.setStatusEnum(DBStatus.LOCAL_EDITED);
-            originalBoard.setOwner(newOwner);
             originalBoard.setId(null);
             originalBoard.setLocalId(null);
+            originalBoard.getBoard().setTitle(newBoardTitle);
+            originalBoard.getBoard().setColor(String.format("%06X", 0xFFFFFF & targetBoardColor));
+            originalBoard.getBoard().setOwnerId(newOwner.getLocalId());
+            originalBoard.setStatusEnum(DBStatus.LOCAL_EDITED);
+            originalBoard.setOwner(newOwner);
             long newBoardId = dataBaseAdapter.createBoardDirectly(originAccountId, originalBoard.getBoard());
             originalBoard.setLocalId(newBoardId);
 
-            for (Stack stack : originalBoard.getStacks()) {
-                stack.setLocalId(null);
-                stack.setId(null);
-                stack.setStatusEnum(DBStatus.LOCAL_EDITED);
-                stack.setAccountId(targetAccountId);
-                stack.setBoardId(newBoardId);
-                dataBaseAdapter.createStack(targetAccountId, stack);
+            boolean isSameAccount = targetAccountId == originAccountId;
+
+            if (isSameAccount) {
+                List<AccessControl> aclList = originalBoard.getParticipants();
+                for (AccessControl acl : aclList) {
+                    acl.setLocalId(null);
+                    acl.setId(null);
+                    acl.setBoardId(newBoardId);
+                    dataBaseAdapter.createAccessControl(targetAccountId, acl);
+                }
             }
+
+            Map<Long, Long> oldToNewLabelIdsDictionary = new HashMap<>();
+
             for (Label label : originalBoard.getLabels()) {
+                Long oldLocalId = label.getLocalId();
                 label.setLocalId(null);
                 label.setId(null);
                 label.setAccountId(targetAccountId);
                 label.setStatusEnum(DBStatus.LOCAL_EDITED);
                 label.setBoardId(newBoardId);
-                dataBaseAdapter.createLabel(targetAccountId, label);
+                long newLocalId = dataBaseAdapter.createLabelDirectly(targetAccountId, label);
+                oldToNewLabelIdsDictionary.put(oldLocalId, newLocalId);
             }
-            Account targetAccount = dataBaseAdapter.getAccountByIdDirectly(targetAccountId);
-            new SyncHelper(serverAdapter, dataBaseAdapter, null)
-                    .setResponseCallback(new IResponseCallback<Boolean>(targetAccount) {
-                        @Override
-                        public void onResponse(Boolean response) {
-                            liveData.postValue(dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, newBoardId));
-                        }
 
-                        @Override
-                        public void onError(Throwable throwable) {
-                            super.onError(throwable);
-                            liveData.postError(throwable);
+            List<Stack> oldStacks = originalBoard.getStacks();
+            for (Stack stack : oldStacks) {
+                Long oldStackId = stack.getLocalId();
+                stack.setLocalId(null);
+                stack.setId(null);
+                stack.setStatusEnum(DBStatus.LOCAL_EDITED);
+                stack.setAccountId(targetAccountId);
+                stack.setBoardId(newBoardId);
+                long createdStackId = dataBaseAdapter.createStack(targetAccountId, stack);
+                if (cloneCards) {
+                    List<FullCard> oldCards = dataBaseAdapter.getFullCardsForStackDirectly(originAccountId, oldStackId, null);
+                    for (FullCard oldCard : oldCards) {
+                        Card newCard = oldCard.getCard();
+                        newCard.setId(null);
+                        newCard.setUserId(newOwner.getLocalId());
+                        newCard.setLocalId(null);
+                        newCard.setStackId(createdStackId);
+                        newCard.setAccountId(targetAccountId);
+                        newCard.setStatusEnum(DBStatus.LOCAL_EDITED);
+                        long createdCardId = dataBaseAdapter.createCardDirectly(targetAccountId, newCard);
+                        if (oldCard.getLabels() != null) {
+                            for (Label oldLabel : oldCard.getLabels()) {
+                                Long newLabelId = oldToNewLabelIdsDictionary.get(oldLabel.getLocalId());
+                                if (newLabelId != null) {
+                                    dataBaseAdapter.createJoinCardWithLabel(newLabelId, createdCardId, DBStatus.LOCAL_EDITED);
+                                } else
+                                    DeckLog.error("ID of created Label is null! Skipping assignment of \"" + oldLabel.getTitle() + "\"...");
+                            }
+                        }
+                        if (isSameAccount && oldCard.getAssignedUsers() != null) {
+                            for (User assignedUser : oldCard.getAssignedUsers()) {
+                                dataBaseAdapter.createJoinCardWithUser(assignedUser.getLocalId(), createdCardId, DBStatus.LOCAL_EDITED);
+                            }
                         }
-                    }).doSyncFor(new BoardDataProvider());
+                    }
+                }
+            }
+            // dont trigger concurrent syncs!
+            List<IResponseCallback<Boolean>> queuedSync = RUNNING_SYNCS.get(targetAccountId);
+            if ((queuedSync == null || queuedSync.isEmpty()) && serverAdapter.hasInternetConnection()) {
+                Account targetAccount = dataBaseAdapter.getAccountByIdDirectly(targetAccountId);
+                ServerAdapter serverAdapterToUse = this.serverAdapter;
+                if (originAccountId != targetAccountId) {
+                    serverAdapterToUse = new ServerAdapter(appContext, targetAccount.getName());
+                }
+                new SyncHelper(serverAdapterToUse, dataBaseAdapter, null)
+                        .setResponseCallback(new IResponseCallback<Boolean>(targetAccount) {
+                            @Override
+                            public void onResponse(Boolean response) {
+                                liveData.postValue(dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, newBoardId));
+                            }
 
+                            @Override
+                            public void onError(Throwable throwable) {
+                                super.onError(throwable);
+                                liveData.postError(throwable);
+                            }
+                        }).doUpSyncFor(new BoardWithStacksAndLabelsUpSyncDataProvider(dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, newBoardId)));
+            } else {
+                liveData.postValue(dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, newBoardId));
+            }
         });
         return liveData;
     }
@@ -624,6 +796,7 @@ public class SyncManager {
                     liveData.postValue(response);
                 }
 
+                @SuppressLint("MissingSuperCall")
                 @Override
                 public void onError(Throwable throwable) {
                     liveData.postError(throwable);
@@ -633,8 +806,8 @@ public class SyncManager {
         return liveData;
     }
 
-    public LiveData<List<FullStack>> getStacksForBoard(long accountId, long localBoardId) {
-        return dataBaseAdapter.getFullStacksForBoard(accountId, localBoardId);
+    public LiveData<List<Stack>> getStacksForBoard(long accountId, long localBoardId) {
+        return dataBaseAdapter.getStacksForBoard(accountId, localBoardId);
     }
 
     public LiveData<FullStack> getStack(long accountId, long localStackId) {
@@ -651,8 +824,7 @@ public class SyncManager {
                     new AccessControlDataProvider(null, board, Collections.singletonList(entity)), entity, getCallbackToLiveDataConverter(account, liveData), ((entity1, response) -> {
                         response.setBoardId(entity.getBoardId());
                         response.setUserId(entity.getUser().getLocalId());
-                    }
-                    )
+                    })
             );
         });
         return liveData;
@@ -687,6 +859,7 @@ public class SyncManager {
                 liveData.postValue(response);
             }
 
+            @SuppressLint("MissingSuperCall")
             @Override
             public void onError(Throwable throwable) {
                 liveData.postError(throwable);
@@ -711,6 +884,7 @@ public class SyncManager {
                             liveData.postValue(response);
                         }
 
+                        @SuppressLint("MissingSuperCall")
                         @Override
                         public void onError(Throwable throwable) {
                             liveData.postError(throwable);
@@ -725,18 +899,30 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<FullStack> createStack(long accountId, @NonNull Stack stack) {
+    public WrappedLiveData<FullStack> createStack(long accountId, @NonNull String title, long boardLocalId) {
         WrappedLiveData<FullStack> liveData = new WrappedLiveData<>();
         doAsync(() -> {
+            Stack stack = new Stack(title, boardLocalId);
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             FullBoard board = dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, stack.getBoardId());
             FullStack fullStack = new FullStack();
-            // TODO set stack order to (highest stack-order from board) + 1 and remove logic from caller
+            stack.setOrder(dataBaseAdapter.getHighestStackOrderInBoard(stack.getBoardId()) + 1);
             stack.setAccountId(accountId);
             stack.setBoardId(board.getLocalId());
             fullStack.setStack(stack);
             fullStack.setAccountId(accountId);
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new StackDataProvider(null, board), fullStack, getCallbackToLiveDataConverter(account, liveData));
+            new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new StackDataProvider(null, board), fullStack, new IResponseCallback<FullStack>(account) {
+                @Override
+                public void onResponse(FullStack response) {
+                    liveData.postValue(response);
+                }
+
+                @SuppressLint("MissingSuperCall")
+                @Override
+                public void onError(Throwable throwable, FullStack entity) {
+                    liveData.postError(throwable, entity);
+                }
+            });
         });
         return liveData;
     }
@@ -754,36 +940,36 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<FullStack> updateStack(@NonNull FullStack stack) {
+    public WrappedLiveData<FullStack> updateStackTitle(long localStackId, @NonNull String newTitle) {
         WrappedLiveData<FullStack> liveData = new WrappedLiveData<>();
         doAsync(() -> {
+            FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(localStackId);
+            FullBoard fullBoard = dataBaseAdapter.getFullBoardByLocalIdDirectly(stack.getAccountId(), stack.getStack().getBoardId());
             Account account = dataBaseAdapter.getAccountByIdDirectly(stack.getAccountId());
-            FullBoard board = dataBaseAdapter.getFullBoardByLocalIdDirectly(stack.getAccountId(), stack.getStack().getBoardId());
-            updateStack(account, board, stack, liveData);
+            stack.getStack().setTitle(newTitle);
+            updateStack(account, fullBoard, stack, liveData);
         });
         return liveData;
-
     }
 
     @AnyThread
     private void updateStack(@NonNull Account account, @NonNull FullBoard board, @NonNull FullStack stack, @Nullable WrappedLiveData<FullStack> liveData) {
-        doAsync(() -> {
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).updateEntity(new StackDataProvider(null, board), stack, new IResponseCallback<FullStack>(account) {
-                @Override
-                public void onResponse(FullStack response) {
-                    if (liveData != null) {
-                        liveData.postValue(response);
-                    }
+        doAsync(() -> new DataPropagationHelper(serverAdapter, dataBaseAdapter).updateEntity(new StackDataProvider(null, board), stack, new IResponseCallback<FullStack>(account) {
+            @Override
+            public void onResponse(FullStack response) {
+                if (liveData != null) {
+                    liveData.postValue(response);
                 }
+            }
 
-                @Override
-                public void onError(Throwable throwable) {
-                    if (liveData != null) {
-                        liveData.postError(throwable);
-                    }
+            @SuppressLint("MissingSuperCall")
+            @Override
+            public void onError(Throwable throwable) {
+                if (liveData != null) {
+                    liveData.postError(throwable);
                 }
-            });
-        });
+            }
+        }));
     }
 
     /**
@@ -813,8 +999,8 @@ public class SyncManager {
         });
     }
 
-    public LiveData<FullCard> getCardByLocalId(long accountId, long cardLocalId) {
-        return dataBaseAdapter.getCardByLocalId(accountId, cardLocalId);
+    public LiveData<FullCardWithProjects> getFullCardWithProjectsByLocalId(long accountId, long cardLocalId) {
+        return dataBaseAdapter.getCardWithProjectsByLocalId(accountId, cardLocalId);
     }
 
     public LiveData<List<FullCard>> getFullCardsForStack(long accountId, long localStackId, @Nullable FilterInformation filter) {
@@ -863,8 +1049,8 @@ public class SyncManager {
 //    }
 
     @AnyThread
-    public LiveData<FullCard> createFullCard(long accountId, long localBoardId, long localStackId, @NonNull FullCard card) {
-        MutableLiveData<FullCard> liveData = new MutableLiveData<>();
+    public WrappedLiveData<FullCard> createFullCard(long accountId, long localBoardId, long localStackId, @NonNull FullCard card) {
+        WrappedLiveData<FullCard> liveData = new WrappedLiveData<>();
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             User owner = dataBaseAdapter.getUserByUidDirectly(accountId, account.getUserName());
@@ -875,7 +1061,7 @@ public class SyncManager {
             card.getCard().setAccountId(accountId);
             card.getCard().setStatusEnum(DBStatus.LOCAL_EDITED);
             card.getCard().setOrder(dataBaseAdapter.getHighestCardOrderInStack(localStackId) + 1);
-            long localCardId = dataBaseAdapter.createCard(accountId, card.getCard());
+            long localCardId = dataBaseAdapter.createCardDirectly(accountId, card.getCard());
             card.getCard().setLocalId(localCardId);
 
             List<User> assignedUsers = card.getAssignedUsers();
@@ -901,11 +1087,28 @@ public class SyncManager {
                 }
             }
 
-            liveData.postValue(card);
+
             if (serverAdapter.hasInternetConnection()) {
                 new SyncHelper(serverAdapter, dataBaseAdapter, null)
-                        .setResponseCallback(IResponseCallback.getDefaultResponseCallback(account))
+                        .setResponseCallback(new IResponseCallback<Boolean>(account) {
+                            @Override
+                            public void onResponse(Boolean response) {
+                                liveData.postValue(card);
+                            }
+
+                            @SuppressLint("MissingSuperCall")
+                            @Override
+                            public void onError(Throwable throwable) {
+                                if (throwable.getClass() == DeckException.class && ((DeckException)throwable).getHint().equals(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET)) {
+                                    liveData.postValue(card);
+                                } else {
+                                    liveData.postError(throwable);
+                                }
+                            }
+                        })
                         .doUpSyncFor(new CardDataProvider(null, board, stack));
+            } else {
+                liveData.postValue(card);
             }
         });
         return liveData;
@@ -917,7 +1120,7 @@ public class SyncManager {
         doAsync(() -> {
             FullCard fullCard = dataBaseAdapter.getFullCardByLocalIdDirectly(card.getAccountId(), card.getLocalId());
             if (fullCard == null) {
-                throw new IllegalArgumentException("card to delete does not exist.");
+                throw new IllegalArgumentException("card with id " + card.getLocalId() + " to delete does not exist.");
             }
             Account account = dataBaseAdapter.getAccountByIdDirectly(card.getAccountId());
             FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getStackId());
@@ -935,12 +1138,12 @@ public class SyncManager {
             FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getCard().getStackId());
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
             card.getCard().setArchived(true);
-            updateCardForArchive(account, stack, board, card, getCallbackToLiveDataConverter(account, liveData));
+            updateCardForArchive(stack, board, card, getCallbackToLiveDataConverter(account, liveData));
         });
         return liveData;
     }
 
-    private void updateCardForArchive(Account account, FullStack stack, Board board, FullCard card, @NonNull IResponseCallback<FullCard> callback) {
+    private void updateCardForArchive(FullStack stack, Board board, FullCard card, @NonNull IResponseCallback<FullCard> callback) {
         new DataPropagationHelper(serverAdapter, dataBaseAdapter).updateEntity(new CardDataProvider(null, board, stack), card, callback);
     }
 
@@ -952,29 +1155,34 @@ public class SyncManager {
             FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getCard().getStackId());
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
             card.getCard().setArchived(false);
-            updateCardForArchive(account, stack, board, card, getCallbackToLiveDataConverter(account, liveData));
+            updateCardForArchive(stack, board, card, getCallbackToLiveDataConverter(account, liveData));
         });
         return liveData;
     }
 
     @AnyThread
-    public WrappedLiveData<Void> archiveCardsInStack(long accountId, long stackLocalId) {
+    public WrappedLiveData<Void> archiveCardsInStack(long accountId, long stackLocalId, @NonNull FilterInformation filterInformation) {
         WrappedLiveData<Void> liveData = new WrappedLiveData<>();
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(stackLocalId);
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
-            List<FullCard> cards = dataBaseAdapter.getFullCardsForStackDirectly(accountId, stackLocalId);
+            List<FullCard> cards = dataBaseAdapter.getFullCardsForStackDirectly(accountId, stackLocalId, filterInformation);
             if (cards.size() > 0) {
                 CountDownLatch latch = new CountDownLatch(cards.size());
                 for (FullCard card : cards) {
+                    if (card.getCard().isArchived()) {
+                        latch.countDown();
+                        continue;
+                    }
                     card.getCard().setArchived(true);
-                    updateCardForArchive(account, stack, board, card, new IResponseCallback<FullCard>(account) {
+                    updateCardForArchive(stack, board, card, new IResponseCallback<FullCard>(account) {
                         @Override
                         public void onResponse(FullCard response) {
                             latch.countDown();
                         }
 
+                        @SuppressLint("MissingSuperCall")
                         @Override
                         public void onError(Throwable throwable) {
                             latch.countDown();
@@ -996,21 +1204,35 @@ public class SyncManager {
     }
 
     @AnyThread
-    public void archiveBoard(@NonNull Board board) {
+    public WrappedLiveData<FullBoard> archiveBoard(@NonNull Board board) {
+        WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
         doAsync(() -> {
-            FullBoard b = dataBaseAdapter.getFullBoardByLocalIdDirectly(board.getAccountId(), board.getLocalId());
-            b.getBoard().setArchived(true);
-            updateBoard(b);
+            try {
+                FullBoard b = dataBaseAdapter.getFullBoardByLocalIdDirectly(board.getAccountId(), board.getLocalId());
+                b.getBoard().setArchived(true);
+                updateBoard(b);
+                liveData.postValue(b);
+            } catch (Throwable e) {
+                liveData.postError(e);
+            }
         });
+        return liveData;
     }
 
     @AnyThread
-    public void dearchiveBoard(@NonNull Board board) {
+    public WrappedLiveData<FullBoard> dearchiveBoard(@NonNull Board board) {
+        WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
         doAsync(() -> {
-            FullBoard b = dataBaseAdapter.getFullBoardByLocalIdDirectly(board.getAccountId(), board.getLocalId());
-            b.getBoard().setArchived(false);
-            updateBoard(b);
+            try {
+                FullBoard b = dataBaseAdapter.getFullBoardByLocalIdDirectly(board.getAccountId(), board.getLocalId());
+                b.getBoard().setArchived(false);
+                updateBoard(b);
+                liveData.postValue(b);
+            } catch (Throwable e) {
+                liveData.postError(e);
+            }
         });
+        return liveData;
     }
 
     @AnyThread
@@ -1055,6 +1277,7 @@ public class SyncManager {
                                 liveData.postValue(dataBaseAdapter.getFullCardByLocalIdDirectly(card.getAccountId(), card.getLocalId()));
                             }
 
+                            @SuppressLint("MissingSuperCall")
                             @Override
                             public void onError(Throwable throwable) {
                                 liveData.postError(throwable);
@@ -1092,39 +1315,44 @@ public class SyncManager {
     public WrappedLiveData<Void> moveCard(long originAccountId, long originCardLocalId, long targetAccountId, long targetBoardLocalId, long targetStackLocalId) {
         return LiveDataHelper.wrapInLiveData(() -> {
 
-            FullCard originalCard = dataBaseAdapter.getFullCardByLocalIdDirectly(originAccountId, originCardLocalId);
+            final FullCard originalCard = dataBaseAdapter.getFullCardByLocalIdDirectly(originAccountId, originCardLocalId);
             int newIndex = dataBaseAdapter.getHighestCardOrderInStack(targetStackLocalId) + 1;
-            FullBoard originalBoard = dataBaseAdapter.getFullBoardByLocalCardIdDirectly(originCardLocalId);
+            final FullBoard originalBoard = dataBaseAdapter.getFullBoardByLocalCardIdDirectly(originCardLocalId);
             // ### maybe shortcut possible? (just moved to another stack)
             if (targetBoardLocalId == originalBoard.getLocalId()) {
                 reorder(originAccountId, originalCard, targetStackLocalId, newIndex);
                 return null;
             }
             // ### get rid of original card where it is now.
-            Card originalInnerCard = originalCard.getCard();
-            deleteCard(originalInnerCard);
+            final Card originalInnerCard = originalCard.getCard();
+            deleteCard(new Card(originalInnerCard));
             // ### clone card itself
-            Card targetCard = originalInnerCard;
-            targetCard.setAccountId(targetAccountId);
-            targetCard.setId(null);
-            targetCard.setLocalId(null);
-            targetCard.setStatusEnum(DBStatus.LOCAL_EDITED);
-            targetCard.setStackId(targetStackLocalId);
-            targetCard.setOrder(newIndex);
-            //TODO: this needs to propagate to server as well, since anything else propagates as well (otherwise card isn't known on server)
-            FullCard fullCardForServerPropagation = new FullCard();
-            fullCardForServerPropagation.setCard(targetCard);
-
-            Account targetAccount = dataBaseAdapter.getAccountByIdDirectly(targetAccountId);
-            FullBoard targetBoard = dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, targetBoardLocalId);
-            FullStack targetFullStack = dataBaseAdapter.getFullStackByLocalIdDirectly(targetStackLocalId);
-            User userOfTargetAccount = dataBaseAdapter.getUserByUidDirectly(targetAccountId, targetAccount.getUserName());
-            CountDownLatch latch = new CountDownLatch(1);
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new CardPropagationDataProvider(null, targetBoard.getBoard(), targetFullStack), fullCardForServerPropagation, new IResponseCallback<FullCard>(targetAccount) {
+            originalInnerCard.setAccountId(targetAccountId);
+            originalInnerCard.setId(null);
+            originalInnerCard.setLocalId(null);
+            originalInnerCard.setStatusEnum(DBStatus.LOCAL_EDITED);
+            originalInnerCard.setStackId(targetStackLocalId);
+            originalInnerCard.setOrder(newIndex);
+            originalInnerCard.setArchived(false);
+            originalInnerCard.setAttachmentCount(0);
+            originalInnerCard.setCommentsUnread(0);
+            final FullCard fullCardForServerPropagation = new FullCard();
+            fullCardForServerPropagation.setCard(originalInnerCard);
+
+            final Account targetAccount = dataBaseAdapter.getAccountByIdDirectly(targetAccountId);
+            final FullBoard targetBoard = dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, targetBoardLocalId);
+            final FullStack targetFullStack = dataBaseAdapter.getFullStackByLocalIdDirectly(targetStackLocalId);
+            final User userOfTargetAccount = dataBaseAdapter.getUserByUidDirectly(targetAccountId, targetAccount.getUserName());
+            final CountDownLatch latch = new CountDownLatch(1);
+            ServerAdapter serverToUse = serverAdapter;
+            if (originAccountId != targetAccountId) {
+                serverToUse = new ServerAdapter(appContext, targetAccount.getName());
+            }
+            new DataPropagationHelper(serverToUse, dataBaseAdapter).createEntity(new CardPropagationDataProvider(null, targetBoard.getBoard(), targetFullStack), fullCardForServerPropagation, new IResponseCallback<FullCard>(targetAccount) {
                 @Override
                 public void onResponse(FullCard response) {
-                    targetCard.setId(response.getId());
-                    targetCard.setLocalId(response.getLocalId());
+                    originalInnerCard.setId(response.getId());
+                    originalInnerCard.setLocalId(response.getLocalId());
                     latch.countDown();
                 }
 
@@ -1134,8 +1362,10 @@ public class SyncManager {
                     throw new RuntimeException("unable to create card in moveCard target", throwable);
                 }
             }, (FullCard entity, FullCard response) -> {
-                response.getCard().setUserId(entity.getCard().getUserId());
+                response.getCard().setUserId(userOfTargetAccount.getLocalId());
                 response.getCard().setStackId(targetFullStack.getLocalId());
+                entity.getCard().setUserId(userOfTargetAccount.getLocalId());
+                entity.getCard().setStackId(targetFullStack.getLocalId());
             });
 
             try {
@@ -1145,7 +1375,7 @@ public class SyncManager {
                 throw new RuntimeException("error fulfilling countDownLatch", e);
             }
 
-            long newCardId = targetCard.getLocalId();
+            long newCardId = originalInnerCard.getLocalId();
 
             // ### clone labels, assign them
             // prepare
@@ -1154,7 +1384,7 @@ public class SyncManager {
             List<AccessControl> aclOfTargetBoard = dataBaseAdapter.getAccessControlByLocalBoardIdDirectly(targetAccountId, targetBoard.getLocalId());
             if (!hasManagePermission) {
                 for (AccessControl accessControl : aclOfTargetBoard) {
-                    if (accessControl.getUserId() == userOfTargetAccount.getLocalId() && accessControl.isPermissionManage()) {
+                    if (accessControl.getUserId().equals(userOfTargetAccount.getLocalId()) && accessControl.isPermissionManage()) {
                         hasManagePermission = true;
                         break;
                     }
@@ -1178,10 +1408,10 @@ public class SyncManager {
                         originalLabel.setLocalId(null);
                         originalLabel.setStatusEnum(DBStatus.LOCAL_EDITED);
                         originalLabel.setAccountId(targetBoard.getAccountId());
-                        createAndAssignLabelToCard(originalBoard.getAccountId(), originalLabel, newCardId);
+                        createAndAssignLabelToCard(targetBoard.getAccountId(), originalLabel, newCardId, serverToUse);
                     }
                 } else {
-                    assignLabelToCard(existingMatch, targetCard);
+                    assignLabelToCard(existingMatch, originalInnerCard, serverToUse);
                 }
             }
 
@@ -1194,7 +1424,7 @@ public class SyncManager {
                     boolean hasViewPermission = targetBoard.getBoard().getOwnerId() == assignedUser.getLocalId();
                     if (!hasViewPermission) {
                         for (AccessControl accessControl : aclOfTargetBoard) {
-                            if (accessControl.getUserId() == userOfTargetAccount.getLocalId()) {
+                            if (accessControl.getUserId().equals(userOfTargetAccount.getLocalId())) {
                                 // ACL exists, so viewing is granted
                                 hasViewPermission = true;
                                 break;
@@ -1202,7 +1432,7 @@ public class SyncManager {
                         }
                     }
                     if (hasViewPermission) {
-                        assignUserToCard(assignedUser, targetCard);
+                        assignUserToCard(assignedUser, originalInnerCard);
                     }
                 }
             }
@@ -1229,25 +1459,28 @@ public class SyncManager {
                     liveData.postValue(response);
                 }
 
+                @SuppressLint("MissingSuperCall")
                 @Override
                 public void onError(Throwable throwable) {
                     liveData.postError(throwable);
                 }
-            }, (entity, response) -> {
-                response.setBoardId(board.getLocalId());
-            });
+            }, (entity, response) -> response.setBoardId(board.getLocalId()));
         });
         return liveData;
     }
 
-    @AnyThread
     public MutableLiveData<Label> createAndAssignLabelToCard(long accountId, @NonNull Label label, long localCardId) {
+        return createAndAssignLabelToCard(accountId, label, localCardId, serverAdapter);
+    }
+
+    @AnyThread
+    private MutableLiveData<Label> createAndAssignLabelToCard(long accountId, @NonNull Label label, long localCardId, ServerAdapter serverAdapterToUse) {
         MutableLiveData<Label> liveData = new MutableLiveData<>();
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             Board board = dataBaseAdapter.getBoardByLocalCardIdDirectly(localCardId);
             label.setAccountId(accountId);
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new LabelDataProvider(null, board, null), label, new IResponseCallback<Label>(account) {
+            new DataPropagationHelper(serverAdapterToUse, dataBaseAdapter).createEntity(new LabelDataProvider(null, board, null), label, new IResponseCallback<Label>(account) {
                 @Override
                 public void onResponse(Label response) {
                     assignLabelToCard(response, dataBaseAdapter.getCardByLocalIdDirectly(accountId, localCardId));
@@ -1317,6 +1550,11 @@ public class SyncManager {
 
     @AnyThread
     public void assignLabelToCard(@NonNull Label label, @NonNull Card card) {
+        assignLabelToCard(label, card, serverAdapter);
+    }
+
+    @AnyThread
+    public void assignLabelToCard(@NonNull Label label, @NonNull Card card, ServerAdapter serverAdapterToUse) {
         doAsync(() -> {
             final long localLabelId = label.getLocalId();
             final long localCardId = card.getLocalId();
@@ -1327,8 +1565,8 @@ public class SyncManager {
             Stack stack = dataBaseAdapter.getStackByLocalIdDirectly(card.getStackId());
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getBoardId());
             Account account = dataBaseAdapter.getAccountByIdDirectly(card.getAccountId());
-            if (serverAdapter.hasInternetConnection()) {
-                serverAdapter.assignLabelToCard(board.getId(), stack.getId(), card.getId(), label.getId(), new IResponseCallback<Void>(account) {
+            if (serverAdapterToUse.hasInternetConnection()) {
+                serverAdapterToUse.assignLabelToCard(board.getId(), stack.getId(), card.getId(), label.getId(), new IResponseCallback<Void>(account) {
 
                     @Override
                     public void onResponse(Void response) {
@@ -1395,11 +1633,6 @@ public class SyncManager {
         return findProposalsForLabelsToAssign(accountId, boardId, -1L);
     }
 
-    // TODO Difference to getFullBoardByid() ??? I think those methods are equal, we should drop one of them.
-    public LiveData<FullBoard> getFullBoard(Long accountId, Long localId) {
-        return dataBaseAdapter.getFullBoardById(accountId, localId);
-    }
-
     public LiveData<User> getUserByLocalId(long accountId, long localId) {
         return dataBaseAdapter.getUserByLocalId(accountId, localId);
     }
@@ -1417,12 +1650,12 @@ public class SyncManager {
         return dataBaseAdapter.searchUserByUidOrDisplayName(accountId, boardId, notYetAssignedToLocalCardId, searchTerm);
     }
 
-    public LiveData<List<User>> searchUserByUidOrDisplayNameForACL(final long accountId, final long notYetAssignedInACL, final String searchTerm) {
-        return dataBaseAdapter.searchUserByUidOrDisplayNameForACL(accountId, notYetAssignedInACL, searchTerm);
+    public UserSearchLiveData searchUserByUidOrDisplayNameForACL() {
+        return new UserSearchLiveData(dataBaseAdapter, serverAdapter);
     }
 
-    public LiveData<Board> getBoard(long accountId, long remoteId) {
-        return dataBaseAdapter.getBoard(accountId, remoteId);
+    public LiveData<Board> getBoardByRemoteId(long accountId, long remoteId) {
+        return dataBaseAdapter.getBoardByRemoteId(accountId, remoteId);
     }
 
     public LiveData<Stack> getStackByRemoteId(long accountId, long localBoardId, long remoteId) {
@@ -1445,10 +1678,6 @@ public class SyncManager {
         return dataBaseAdapter.searchNotYetAssignedLabelsByTitle(accountId, boardId, notYetAssignedToLocalCardId, searchTerm);
     }
 
-    public String getServerUrl() {
-        return serverAdapter.getServerUrl();
-    }
-
     /**
      * @see <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/360">reenable reorder</a>
      */
@@ -1456,7 +1685,7 @@ public class SyncManager {
     public void reorder(long accountId, @NonNull FullCard movedCard, long newStackId, int newIndex) {
         doAsync(() -> {
             // read cards of new stack
-            List<FullCard> cardsOfNewStack = dataBaseAdapter.getFullCardsForStackDirectly(accountId, newStackId);
+            List<FullCard> cardsOfNewStack = dataBaseAdapter.getFullCardsForStackDirectly(accountId, newStackId, null);
             int newOrder = newIndex;
             if (cardsOfNewStack.size() > newIndex) {
                 newOrder = cardsOfNewStack.get(newIndex).getCard().getOrder();
@@ -1526,7 +1755,7 @@ public class SyncManager {
                 Stack stack = dataBaseAdapter.getStackByLocalIdDirectly(movedCard.getCard().getStackId());
                 FullBoard board = dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, stack.getBoardId());
                 Account account = dataBaseAdapter.getAccountByIdDirectly(movedCard.getCard().getAccountId());
-                new SyncHelper(serverAdapter, dataBaseAdapter, new Date()).setResponseCallback(new IResponseCallback<Boolean>(account) {
+                new SyncHelper(serverAdapter, dataBaseAdapter, Instant.now()).setResponseCallback(new IResponseCallback<Boolean>(account) {
                     @Override
                     public void onResponse(Boolean response) {
                         // doNothing();
@@ -1597,7 +1826,7 @@ public class SyncManager {
     }
 
     private void reorderAscending(@NonNull Card movedCard, @NonNull List<Card> cardsToReorganize, int startingAtOrder) {
-        Date now = new Date();
+        final Instant now = Instant.now();
         for (Card card : cardsToReorganize) {
             card.setOrder(startingAtOrder);
             if (card.getStatus() == DBStatus.UP_TO_DATE.getId()) {
@@ -1625,7 +1854,7 @@ public class SyncManager {
         WrappedLiveData<Attachment> liveData = new WrappedLiveData<>();
         doAsync(() -> {
             Attachment attachment = populateAttachmentEntityForFile(new Attachment(), localCardId, mimeType, file);
-            Date now = new Date();
+            final Instant now = Instant.now();
             attachment.setLastModifiedLocal(now);
             attachment.setCreatedAt(now);
             FullCard card = dataBaseAdapter.getFullCardByLocalIdDirectly(accountId, localCardId);
@@ -1645,7 +1874,7 @@ public class SyncManager {
         WrappedLiveData<Attachment> liveData = new WrappedLiveData<>();
         doAsync(() -> {
             Attachment attachment = populateAttachmentEntityForFile(existing, existing.getCardId(), mimeType, file);
-            attachment.setLastModifiedLocal(new Date());
+            attachment.setLastModifiedLocal(Instant.now());
             if (serverAdapter.hasInternetConnection()) {
                 FullCard card = dataBaseAdapter.getFullCardByLocalIdDirectly(accountId, existing.getCardId());
                 Stack stack = dataBaseAdapter.getStackByLocalIdDirectly(card.getCard().getStackId());
@@ -1658,6 +1887,7 @@ public class SyncManager {
                                 liveData.postValue(response);
                             }
 
+                            @SuppressLint("MissingSuperCall")
                             @Override
                             public void onError(Throwable throwable) {
                                 liveData.postError(throwable);
@@ -1670,15 +1900,14 @@ public class SyncManager {
 
     @AnyThread
     private static Attachment populateAttachmentEntityForFile(@NonNull Attachment target, long localCardId, @NonNull String mimeType, @NonNull File file) {
-        Attachment attachment = target;
-        attachment.setCardId(localCardId);
-        attachment.setMimetype(mimeType);
-        attachment.setData(file.getName());
-        attachment.setFilename(file.getName());
-        attachment.setBasename(file.getName());
-        attachment.setLocalPath(file.getAbsolutePath());
-        attachment.setFilesize(file.length());
-        return attachment;
+        target.setCardId(localCardId);
+        target.setMimetype(mimeType);
+        target.setData(file.getName());
+        target.setFilename(file.getName());
+        target.setBasename(file.getName());
+        target.setLocalPath(file.getAbsolutePath());
+        target.setFilesize(file.length());
+        return target;
     }
 
     @AnyThread
@@ -1726,7 +1955,27 @@ public class SyncManager {
         doAsync(() -> dataBaseAdapter.deleteSingleCardWidget(widgetId));
     }
 
-    private static class BooleanResultHolder {
-        public boolean result = true;
+    public void addStackWidget(int appWidgetId, long accountId, long stackId, boolean darkTheme) {
+        doAsync(() -> dataBaseAdapter.createStackWidget(appWidgetId, accountId, stackId, darkTheme));
+    }
+
+    @WorkerThread
+    public StackWidgetModel getStackWidgetModelDirectly(int appWidgetId) throws NoSuchElementException {
+        final StackWidgetModel model = dataBaseAdapter.getStackWidgetModelDirectly(appWidgetId);
+        if (model == null) {
+            throw new NoSuchElementException();
+        }
+        return model;
+    }
+
+    public void deleteStackWidgetModel(int appWidgetId) {
+        doAsync(() -> dataBaseAdapter.deleteStackWidget(appWidgetId));
+    }
+
+    /**
+     * FIXME https://github.com/stefan-niedermann/nextcloud-deck/issues/640
+     */
+    public static boolean ignoreExceptionOnVoidError(Throwable t) {
+        return t instanceof NullPointerException && "Attempt to invoke interface method 'void io.reactivex.disposables.Disposable.dispose()' on a null object reference".equals(t.getMessage());
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/ServerAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/ServerAdapter.java
index 4f41173e9..bff8ddfdb 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/ServerAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/ServerAdapter.java
@@ -13,18 +13,14 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.preference.PreferenceManager;
 
+import com.nextcloud.android.sso.api.ParsedResponse;
+
 import java.io.File;
-import java.text.DateFormat;
-import java.text.SimpleDateFormat;
-import java.util.Date;
 import java.util.List;
-import java.util.Locale;
-import java.util.TimeZone;
 
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.api.ApiProvider;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
-import it.niedermann.nextcloud.deck.api.LastSyncUtil;
 import it.niedermann.nextcloud.deck.api.RequestHelper;
 import it.niedermann.nextcloud.deck.exceptions.OfflineException;
 import it.niedermann.nextcloud.deck.model.AccessControl;
@@ -39,11 +35,12 @@ import it.niedermann.nextcloud.deck.model.full.FullStack;
 import it.niedermann.nextcloud.deck.model.ocs.Capabilities;
 import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.OcsComment;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectList;
+import it.niedermann.nextcloud.deck.model.ocs.user.GroupMemberUIDs;
 import it.niedermann.nextcloud.deck.model.ocs.user.OcsUser;
 import it.niedermann.nextcloud.deck.model.ocs.user.OcsUserList;
 import it.niedermann.nextcloud.deck.model.propagation.CardUpdate;
 import it.niedermann.nextcloud.deck.model.propagation.Reorder;
-import it.niedermann.nextcloud.deck.util.DateUtil;
 import okhttp3.MediaType;
 import okhttp3.MultipartBody;
 import okhttp3.RequestBody;
@@ -53,18 +50,11 @@ import static it.niedermann.nextcloud.deck.util.MimeTypeUtil.TEXT_PLAIN;
 
 public class ServerAdapter {
 
-    private String prefKeyWifiOnly;
-
-    private static final DateFormat API_FORMAT =
-            new SimpleDateFormat("E, dd MMM yyyy hh:mm:ss z", Locale.US);
-
-    static {
-        API_FORMAT.setTimeZone(TimeZone.getTimeZone("GMT"));
-    }
+    private final String prefKeyWifiOnly;
 
     @NonNull
-    private Context applicationContext;
-    private ApiProvider provider;
+    private final Context applicationContext;
+    private final ApiProvider provider;
 
     public ServerAdapter(@NonNull Context applicationContext) {
         this(applicationContext, null);
@@ -135,32 +125,35 @@ public class ServerAdapter {
 //        return lastSyncHeader;
     }
 
-    // TODO not used
-    private Date getLastSync(long accountId) {
-        Date lastSync = DateUtil.nowInGMT();
-        lastSync.setTime(LastSyncUtil.getLastSync(accountId));
+    public void getBoards(IResponseCallback<ParsedResponse<List<FullBoard>>> responseCallback) {
+        RequestHelper.request(provider, () ->
+                        provider.getDeckAPI().getBoards(true, getLastSyncDateFormatted(responseCallback.getAccount().getId()), responseCallback.getAccount().getBoardsEtag()),
+                responseCallback);
+    }
 
-        return lastSync;
+    public void getCapabilities(String eTag, IResponseCallback<ParsedResponse<Capabilities>> responseCallback) {
+        ensureInternetConnection();
+        RequestHelper.request(provider, () -> provider.getNextcloudAPI().getCapabilities(eTag), responseCallback);
     }
 
-    public void getBoards(IResponseCallback<List<FullBoard>> responseCallback) {
-        RequestHelper.request(provider, () ->
-                        provider.getDeckAPI().getBoards(true, getLastSyncDateFormatted(responseCallback.getAccount().getId())),
-                responseCallback);
+    public void getProjectsForCard(long remoteCardId, IResponseCallback<OcsProjectList> responseCallback) {
+        ensureInternetConnection();
+        RequestHelper.request(provider, () -> provider.getNextcloudAPI().getProjectsForCard(remoteCardId), responseCallback);
     }
 
-    public void getCapabilities(IResponseCallback<Capabilities> responseCallback) {
+    public void searchUser(String searchTerm, IResponseCallback<OcsUserList> responseCallback) {
         ensureInternetConnection();
-        RequestHelper.request(provider, () -> provider.getNextcloudAPI().getCapabilities(), responseCallback);
+        RequestHelper.request(provider, () -> provider.getNextcloudAPI().searchUser(searchTerm), responseCallback);
     }
-    public void getAllOcsUsers(IResponseCallback<OcsUserList> responseCallback) {
+
+    public void getSingleUserData(String userUid, IResponseCallback<OcsUser> responseCallback) {
         ensureInternetConnection();
-        RequestHelper.request(provider, () -> provider.getNextcloudAPI().getAllUsers(), responseCallback);
+        RequestHelper.request(provider, () -> provider.getNextcloudAPI().getSingleUserData(userUid), responseCallback);
     }
 
-    public void getOcsUserDetails(String ocsUserName, IResponseCallback<OcsUser> responseCallback) {
+    public void searchGroupMembers(String groupUID, IResponseCallback<GroupMemberUIDs> responseCallback) {
         ensureInternetConnection();
-        RequestHelper.request(provider, () -> provider.getNextcloudAPI().getUserDetails(ocsUserName), responseCallback);
+        RequestHelper.request(provider, () -> provider.getNextcloudAPI().searchGroupMembers(groupUID), responseCallback);
     }
 
     public void getActivitiesForCard(long cardId, IResponseCallback<List<it.niedermann.nextcloud.deck.model.ocs.Activity>> responseCallback) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DataBaseAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DataBaseAdapter.java
index c643289bd..982844f06 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DataBaseAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DataBaseAdapter.java
@@ -2,16 +2,15 @@ package it.niedermann.nextcloud.deck.persistence.sync.adapters.db;
 
 import android.content.Context;
 
+import androidx.annotation.AnyThread;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.WorkerThread;
 import androidx.lifecycle.LiveData;
 import androidx.sqlite.db.SimpleSQLiteQuery;
 
-import org.jetbrains.annotations.NotNull;
-
+import java.time.Instant;
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
@@ -26,10 +25,12 @@ import it.niedermann.nextcloud.deck.model.JoinCardWithUser;
 import it.niedermann.nextcloud.deck.model.Label;
 import it.niedermann.nextcloud.deck.model.Stack;
 import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.model.appwidgets.StackWidgetModel;
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 import it.niedermann.nextcloud.deck.model.enums.EDueType;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.model.full.FullCardWithProjects;
 import it.niedermann.nextcloud.deck.model.full.FullSingleCardWidgetModel;
 import it.niedermann.nextcloud.deck.model.full.FullStack;
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
@@ -39,10 +40,16 @@ import it.niedermann.nextcloud.deck.model.ocs.Activity;
 import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.Mention;
 import it.niedermann.nextcloud.deck.model.ocs.comment.full.FullDeckComment;
+import it.niedermann.nextcloud.deck.model.ocs.projects.JoinCardWithProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.model.relations.UserInBoard;
+import it.niedermann.nextcloud.deck.model.relations.UserInGroup;
 import it.niedermann.nextcloud.deck.model.widget.singlecard.SingleCardWidgetModel;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 import it.niedermann.nextcloud.deck.ui.widget.singlecard.SingleCardWidget;
+import it.niedermann.nextcloud.deck.ui.widget.stack.StackWidget;
 
 import static androidx.lifecycle.Transformations.distinctUntilChanged;
 
@@ -57,28 +64,28 @@ public class DataBaseAdapter {
         this.db = DeckDatabase.getInstance(applicationContext);
     }
 
-    @NotNull
+    @NonNull
     public Context getContext() {
         return context;
     }
 
     private <T extends AbstractRemoteEntity> void markAsEditedIfNeeded(T entity, boolean setStatus) {
         if (!setStatus) return;
-        entity.setLastModifiedLocal(new Date()); // now.
+        entity.setLastModifiedLocal(Instant.now());
         entity.setStatusEnum(DBStatus.LOCAL_EDITED);
     }
 
     private <T extends AbstractRemoteEntity> void markAsDeletedIfNeeded(T entity, boolean setStatus) {
         if (!setStatus) return;
         entity.setStatusEnum(DBStatus.LOCAL_DELETED);
-        entity.setLastModifiedLocal(new Date()); // now.
+        entity.setLastModifiedLocal(Instant.now());
     }
 
     public LiveData<Boolean> hasAccounts() {
         return LiveDataHelper.postCustomValue(db.getAccountDao().countAccounts(), data -> data != null && data > 0);
     }
 
-    public LiveData<Board> getBoard(long accountId, long remoteId) {
+    public LiveData<Board> getBoardByRemoteId(long accountId, long remoteId) {
         return distinctUntilChanged(db.getBoardDao().getBoardByRemoteId(accountId, remoteId));
     }
 
@@ -180,24 +187,66 @@ public class DataBaseAdapter {
         if (filter == null) {
             return LiveDataHelper.interceptLiveData(db.getCardDao().getFullCardsForStack(accountId, localStackId), this::filterRelationsForCard);
         }
+        return LiveDataHelper.interceptLiveData(db.getCardDao().getFilteredFullCardsForStack(getQueryForFilter(filter, accountId, localStackId)), this::filterRelationsForCard);
+
+    }
+
+    private void fillSqlWithListValues(StringBuilder query, List<Object> args, @NonNull List<? extends IRemoteEntity> entities) {
+        for (int i = 0; i < entities.size(); i++) {
+            if (i > 0) {
+                query.append(", ");
+            }
+            query.append("?");
+            args.add(entities.get(i).getLocalId());
+        }
+    }
+
+    @WorkerThread
+    public List<FullCard> getFullCardsForStackDirectly(long accountId, long localStackId, FilterInformation filter) {
+        if (filter == null) {
+            return db.getCardDao().getFullCardsForStackDirectly(accountId, localStackId);
+        }
+        List<Object> args = new ArrayList<>();
+        args.add(accountId);
+        args.add(localStackId);
+
+        return db.getCardDao().getFilteredFullCardsForStackDirectly(getQueryForFilter(filter, accountId, localStackId));
+    }
 
+    @AnyThread
+    private SimpleSQLiteQuery getQueryForFilter(FilterInformation filter, long accountId, long localStackId) {
         List<Object> args = new ArrayList<>();
-        StringBuilder query = new StringBuilder("SELECT * FROM card c " +
-                "WHERE accountId = ? AND stackId = ? ");
         args.add(accountId);
         args.add(localStackId);
+        StringBuilder query = new StringBuilder("SELECT * FROM card c " +
+                "WHERE accountId = ? AND stackId = ? ");
 
         if (!filter.getLabels().isEmpty()) {
-            query.append("and exists(select 1 from joincardwithlabel j where c.localId = cardId and labelId in (");
+            query.append("and (exists(select 1 from joincardwithlabel j where c.localId = cardId and labelId in (");
             fillSqlWithListValues(query, args, filter.getLabels());
             query.append(") and j.status<>3) ");
+            if (filter.isNoAssignedLabel()) {
+                query.append("or not exists(select 1 from joincardwithlabel j where c.localId = cardId and j.status<>3)) ");
+            } else {
+                query.append(") ");
+            }
+        } else if (filter.isNoAssignedLabel()) {
+            query.append("and not exists(select 1 from joincardwithlabel j where c.localId = cardId and j.status<>3) ");
         }
 
         if (!filter.getUsers().isEmpty()) {
-            query.append("and exists(select 1 from joincardwithuser j where c.localId = cardId and userId in (");
+            query.append("and (exists(select 1 from joincardwithuser j where c.localId = cardId and userId in (");
             fillSqlWithListValues(query, args, filter.getUsers());
             query.append(") and j.status<>3) ");
+            if (filter.isNoAssignedUser()) {
+                query.append("or not exists(select 1 from joincardwithuser j where c.localId = cardId and j.status<>3)) ");
+            } else {
+                query.append(") ");
+            }
+        } else if (filter.isNoAssignedUser()) {
+            query.append("and not exists(select 1 from joincardwithuser j where c.localId = cardId and j.status<>3) ");
         }
+
         if (filter.getDueType() != EDueType.NO_FILTER) {
             switch (filter.getDueType()) {
                 case NO_DUE:
@@ -219,24 +268,11 @@ public class DataBaseAdapter {
                     throw new IllegalArgumentException("Xou need to add your new EDueType value\"" + filter.getDueType() + "\" here!");
             }
         }
-        query.append(" and status<>3 order by `order`, createdAt asc;");
-        return LiveDataHelper.interceptLiveData(db.getCardDao().getFilteredFullCardsForStack(new SimpleSQLiteQuery(query.toString(), args.toArray())), this::filterRelationsForCard);
-
-    }
-
-    private void fillSqlWithListValues(StringBuilder query, List<Object> args, @NonNull List<? extends IRemoteEntity> entities) {
-        for (int i = 0; i < entities.size(); i++) {
-            if (i > 0) {
-                query.append(", ");
-            }
-            query.append("?");
-            args.add(entities.get(i).getLocalId());
+        if (filter.getArchiveStatus() != FilterInformation.EArchiveStatus.ALL) {
+            query.append(" and c.archived = " + (filter.getArchiveStatus() == FilterInformation.EArchiveStatus.ARCHIVED ? 1 : 0));
         }
-    }
-
-    @WorkerThread
-    public List<FullCard> getFullCardsForStackDirectly(long accountId, long localStackId) {
-        return db.getCardDao().getFullCardsForStackDirectly(accountId, localStackId);
+        query.append(" and status<>3 order by `order`, createdAt asc;");
+        return new SimpleSQLiteQuery(query.toString(), args.toArray());
     }
 
     @WorkerThread
@@ -244,17 +280,20 @@ public class DataBaseAdapter {
         return db.getUserDao().getUserByUidDirectly(accountId, uid);
     }
 
+    @WorkerThread
     public long createUser(long accountId, User user) {
         user.setAccountId(accountId);
         return db.getUserDao().insert(user);
     }
 
+    @WorkerThread
     public void updateUser(long accountId, User user, boolean setStatus) {
         markAsEditedIfNeeded(user, setStatus);
         user.setAccountId(accountId);
         db.getUserDao().update(user);
     }
 
+    @AnyThread
     public LiveData<Label> getLabelByRemoteId(long accountId, long remoteId) {
         return distinctUntilChanged(db.getLabelDao().getLabelByRemoteId(accountId, remoteId));
     }
@@ -264,7 +303,8 @@ public class DataBaseAdapter {
         return db.getLabelDao().getLabelByRemoteIdDirectly(accountId, remoteId);
     }
 
-    public long createLabel(long accountId, @NonNull Label label) {
+    @WorkerThread
+    public long createLabelDirectly(long accountId, @NonNull Label label) {
         label.setAccountId(accountId);
         return db.getLabelDao().insert(label);
     }
@@ -320,6 +360,8 @@ public class DataBaseAdapter {
             // readded!
             existing.setStatusEnum(DBStatus.LOCAL_EDITED);
             db.getJoinCardWithUserDao().update(existing);
+        } else if (existing != null) {
+            return;
         } else {
             JoinCardWithUser join = new JoinCardWithUser();
             join.setCardId(localCardId);
@@ -344,6 +386,28 @@ public class DataBaseAdapter {
         db.getJoinBoardWithLabelDao().deleteByBoardId(localBoardId);
     }
 
+    public void deleteGroupMembershipsOfGroup(Long localGroupUserId) {
+        db.getUserInGroupDao().deleteByGroupId(localGroupUserId);
+    }
+
+    public void deleteBoardMembershipsOfBoard(Long localBoardId) {
+        db.getUserInBoardDao().deleteByBoardId(localBoardId);
+    }
+
+    public void addUserToGroup(Long localGroupUserId, Long localGroupMemberId) {
+        UserInGroup relation = new UserInGroup();
+        relation.setGroupId(localGroupUserId);
+        relation.setMemberId(localGroupMemberId);
+        db.getUserInGroupDao().insert(relation);
+    }
+
+    public void addUserToBoard(Long localUserId, Long localBoardId) {
+        UserInBoard relation = new UserInBoard();
+        relation.setBoardId(localBoardId);
+        relation.setUserId(localUserId);
+        db.getUserInBoardDao().insert(relation);
+    }
+
     public void updateLabel(Label label, boolean setStatus) {
         markAsEditedIfNeeded(label, setStatus);
         db.getLabelDao().update(label);
@@ -391,6 +455,10 @@ public class DataBaseAdapter {
         return distinctUntilChanged(db.getAccountDao().getAllAccounts());
     }
 
+    public LiveData<List<Board>> getBoards(long accountId) {
+        return distinctUntilChanged(db.getBoardDao().getBoardsForAccount(accountId));
+    }
+
     public LiveData<List<Board>> getBoards(long accountId, boolean archived) {
         return distinctUntilChanged(
                 archived
@@ -431,8 +499,8 @@ public class DataBaseAdapter {
         db.getBoardDao().update(board);
     }
 
-    public LiveData<List<FullStack>> getFullStacksForBoard(long accountId, long localBoardId) {
-        return distinctUntilChanged(db.getStackDao().getFullStacksForBoard(accountId, localBoardId));
+    public LiveData<List<Stack>> getStacksForBoard(long accountId, long localBoardId) {
+        return distinctUntilChanged(db.getStackDao().getStacksForBoard(accountId, localBoardId));
     }
 
     @WorkerThread
@@ -440,27 +508,36 @@ public class DataBaseAdapter {
         return db.getStackDao().getFullStacksForBoardDirectly(accountId, localBoardId);
     }
 
+    @AnyThread
     public LiveData<FullStack> getStack(long accountId, long localStackId) {
         return distinctUntilChanged(db.getStackDao().getFullStack(accountId, localStackId));
     }
 
+    @WorkerThread
     public long createStack(long accountId, Stack stack) {
         stack.setAccountId(accountId);
         return db.getStackDao().insert(stack);
     }
 
+    @WorkerThread
     public void deleteStack(Stack stack, boolean setStatus) {
         markAsDeletedIfNeeded(stack, setStatus);
         db.getStackDao().update(stack);
     }
 
+    @WorkerThread
     public void deleteStackPhysically(Stack stack) {
         db.getStackDao().delete(stack);
     }
 
+    @WorkerThread
     public void updateStack(Stack stack, boolean setStatus) {
         markAsEditedIfNeeded(stack, setStatus);
         db.getStackDao().update(stack);
+        if (db.getStackWidgetModelDao().containsStackLocalId(stack.getLocalId())) {
+            DeckLog.info("Notifying " + StackWidget.class.getSimpleName() + " about card changes for \"" + stack.getTitle() + "\"");
+            StackWidget.notifyDatasetChanged(context);
+        }
     }
 
     @WorkerThread
@@ -468,10 +545,16 @@ public class DataBaseAdapter {
         return db.getCardDao().getCardByLocalIdDirectly(accountId, localCardId);
     }
 
+    @AnyThread
     public LiveData<FullCard> getCardByLocalId(long accountId, long localCardId) {
         return LiveDataHelper.interceptLiveData(db.getCardDao().getFullCardByLocalId(accountId, localCardId), this::filterRelationsForCard);
     }
 
+    @AnyThread
+    public LiveData<FullCardWithProjects> getCardWithProjectsByLocalId(long accountId, long localCardId) {
+        return LiveDataHelper.interceptLiveData(db.getCardDao().getFullCardWithProjectsByLocalId(accountId, localCardId), this::filterRelationsForCard);
+    }
+
     @WorkerThread
     public List<FullCard> getLocallyChangedCardsDirectly(long accountId) {
         return db.getCardDao().getLocallyChangedCardsDirectly(accountId);
@@ -482,15 +565,27 @@ public class DataBaseAdapter {
         return db.getCardDao().getLocallyChangedCardsByLocalStackIdDirectly(accountId, localStackId);
     }
 
-    public long createCard(long accountId, Card card) {
+    @WorkerThread
+    public long createCardDirectly(long accountId, Card card) {
         card.setAccountId(accountId);
-        return db.getCardDao().insert(card);
+        long newCardId = db.getCardDao().insert(card);
+
+        notifyStackWidgetsIfNeeded(card.getTitle(), card.getStackId());
+
+        return newCardId;
     }
 
-    public int getHighestCardOrderInStack(long localStackId){
+    @WorkerThread
+    public int getHighestCardOrderInStack(long localStackId) {
         return db.getCardDao().getHighestOrderInStack(localStackId);
     }
 
+    @WorkerThread
+    public int getHighestStackOrderInBoard(long localBoardId) {
+        return db.getStackDao().getHighestStackOrderInBoard(localBoardId);
+    }
+
+    @WorkerThread
     public void deleteCard(Card card, boolean setStatus) {
         markAsDeletedIfNeeded(card, setStatus);
         if (setStatus) {
@@ -498,21 +593,35 @@ public class DataBaseAdapter {
         } else {
             deleteCardPhysically(card);
         }
+
+        notifyStackWidgetsIfNeeded(card.getTitle(), card.getStackId());
     }
 
+    @WorkerThread
     public void deleteCardPhysically(Card card) {
         db.getCardDao().delete(card);
     }
 
+    @WorkerThread
     public void updateCard(@NonNull Card card, boolean setStatus) {
         markAsEditedIfNeeded(card, setStatus);
+        Long originalStackLocalId = db.getCardDao().getLocalStackIdByLocalCardId(card.getLocalId());
         db.getCardDao().update(card);
         if (db.getSingleCardWidgetModelDao().containsCardLocalId(card.getLocalId())) {
-            DeckLog.info("Notifying widget about card changes for \"" + card.getTitle() + "\"");
+            DeckLog.info("Notifying " + SingleCardWidget.class.getSimpleName() + " about card changes for \"" + card.getTitle() + "\"");
             SingleCardWidget.notifyDatasetChanged(context);
         }
+        notifyStackWidgetsIfNeeded(card.getTitle(), card.getStackId(), originalStackLocalId);
+    }
+
+    private void notifyStackWidgetsIfNeeded(String cardTitle, long... affectedStackIds) {
+        if (db.getStackWidgetModelDao().containsStackLocalId(affectedStackIds)) {
+            DeckLog.info("Notifying " + StackWidget.class.getSimpleName() + " about card changes for \"" + cardTitle + "\"");
+            StackWidget.notifyDatasetChanged(context);
+        }
     }
 
+    @WorkerThread
     public long createAccessControl(long accountId, @NonNull AccessControl entity) {
         entity.setAccountId(accountId);
         return db.getAccessControlDao().insert(entity);
@@ -571,9 +680,9 @@ public class DataBaseAdapter {
         return db.getUserDao().searchUserByUidOrDisplayName(accountId, boardId, notYetAssignedToLocalCardId, "%" + searchTerm.trim() + "%");
     }
 
-    public LiveData<List<User>> searchUserByUidOrDisplayNameForACL(final long accountId, final long notYetAssignedToACL, final String searchTerm) {
+    public List<User> searchUserByUidOrDisplayNameForACLDirectly(final long accountId, final long notYetAssignedToACL, final String searchTerm) {
         validateSearchTerm(searchTerm);
-        return db.getUserDao().searchUserByUidOrDisplayNameForACL(accountId, notYetAssignedToACL, "%" + searchTerm.trim() + "%");
+        return db.getUserDao().searchUserByUidOrDisplayNameForACLDirectly(accountId, notYetAssignedToACL, "%" + searchTerm.trim() + "%");
     }
 
     public LiveData<List<Label>> searchNotYetAssignedLabelsByTitle(final long accountId, final long boardId, final long notYetAssignedToLocalCardId, String searchTerm) {
@@ -618,9 +727,14 @@ public class DataBaseAdapter {
         return db.getAttachmentDao().getLocallyChangedAttachmentsDirectly(accountId);
     }
 
+    @WorkerThread
+    public List<Attachment> getLocallyChangedAttachmentsForStackDirectly(long localStackId) {
+        return db.getAttachmentDao().getLocallyChangedAttachmentsForStackDirectly(localStackId);
+    }
+
     public long createAttachment(long accountId, @NonNull Attachment attachment) {
         attachment.setAccountId(accountId);
-        attachment.setCreatedAt(new Date());
+        attachment.setCreatedAt(Instant.now());
         return db.getAttachmentDao().insert(attachment);
     }
 
@@ -720,16 +834,24 @@ public class DataBaseAdapter {
         return db.getJoinCardWithLabelDao().getAllDeletedJoinsWithRemoteIDs();
     }
 
-    public List<JoinCardWithLabel> getAllChangedJoins() {
+    public List<JoinCardWithLabel> getAllChangedLabelJoins() {
         return db.getJoinCardWithLabelDao().getAllChangedJoins();
     }
 
-    public JoinCardWithLabel getRemoteIdsForJoin(Long localCardId, Long localLabelId) {
+    public List<JoinCardWithLabel> getAllChangedLabelJoinsForStack(Long localStackId) {
+        return db.getJoinCardWithLabelDao().getAllChangedJoinsForStack(localStackId);
+    }
+
+    public JoinCardWithLabel getAllChangedLabelJoinsWithRemoteIDs(Long localCardId, Long localLabelId) {
         return db.getJoinCardWithLabelDao().getRemoteIdsForJoin(localCardId, localLabelId);
     }
 
-    public List<JoinCardWithUser> getAllDeletedUserJoinsWithRemoteIDs() {
-        return db.getJoinCardWithUserDao().getDeletedJoinsWithRemoteIDs();
+    public List<JoinCardWithUser> getAllChangedUserJoinsWithRemoteIDs() {
+        return db.getJoinCardWithUserDao().getChangedJoinsWithRemoteIDs();
+    }
+
+    public List<JoinCardWithUser> getAllChangedUserJoinsWithRemoteIDsForStack(Long localStackId) {
+        return db.getJoinCardWithUserDao().getChangedJoinsWithRemoteIDsForStack(localStackId);
     }
 
     public void deleteJoinedLabelForCardPhysicallyByRemoteIDs(Long accountId, Long remoteCardId, Long remoteLabelId) {
@@ -837,11 +959,17 @@ public class DataBaseAdapter {
         return db.getCommentDao().getCommentByLocalCardIdDirectly(localCardId);
     }
 
+    @WorkerThread
     public List<Card> getCardsWithLocallyChangedCommentsDirectly(Long accountId) {
         return db.getCardDao().getCardsWithLocallyChangedCommentsDirectly(accountId);
     }
 
     @WorkerThread
+    public List<Card> getCardsWithLocallyChangedCommentsForStackDirectly(Long localStackId) {
+        return db.getCardDao().getCardsWithLocallyChangedCommentsForStackDirectly(localStackId);
+    }
+
+    @WorkerThread
     public Long getLocalStackIdByRemoteStackIdDirectly(long accountId, Long stackId) {
         return db.getStackDao().getLocalStackIdByRemoteStackIdDirectly(accountId, stackId);
     }
@@ -910,11 +1038,89 @@ public class DataBaseAdapter {
         db.getSingleCardWidgetModelDao().delete(model);
     }
 
+    public long createStackWidget(int appWidgetId, long accountId, long stackId, boolean darkTheme) {
+        StackWidgetModel model = new StackWidgetModel();
+        model.setAppWidgetId(appWidgetId);
+        model.setAccountId(accountId);
+        model.setStackId(stackId);
+        model.setDarkTheme(darkTheme);
+
+        return db.getStackWidgetModelDao().insert(model);
+    }
+
+    public StackWidgetModel getStackWidgetModelDirectly(int appWidgetId) {
+        return db.getStackWidgetModelDao().getStackWidgetByAppWidgetIdDirectly(appWidgetId);
+    }
+
+    public void deleteStackWidget(int appWidgetId) {
+        StackWidgetModel model = new StackWidgetModel();
+        model.setAppWidgetId(appWidgetId);
+        db.getStackWidgetModelDao().delete(model);
+    }
+
     public LiveData<List<Account>> readAccountsForHostWithReadAccessToBoard(String host, long boardRemoteId) {
-        return db.getAccountDao().readAccountsForHostWithReadAccessToBoard("%"+host+"%", boardRemoteId);
+        return db.getAccountDao().readAccountsForHostWithReadAccessToBoard("%" + host + "%", boardRemoteId);
     }
 
     public List<Account> readAccountsForHostWithReadAccessToBoardDirectly(String host, long boardRemoteId) {
-        return db.getAccountDao().readAccountsForHostWithReadAccessToBoardDirectly("%"+host+"%", boardRemoteId);
+        return db.getAccountDao().readAccountsForHostWithReadAccessToBoardDirectly("%" + host + "%", boardRemoteId);
+    }
+
+    public Board getBoardForAccountByNameDirectly(long account, String title) {
+        return db.getBoardDao().getBoardForAccountByNameDirectly(account, title);
+    }
+
+    public OcsProject getProjectByRemoteIdDirectly(long accountId, Long remoteId) {
+        return db.getOcsProjectDao().getProjectByRemoteIdDirectly(accountId, remoteId);
+    }
+
+    public Long createProjectDirectly(long accountId, OcsProject entity) {
+        entity.setAccountId(accountId);
+        return db.getOcsProjectDao().insert(entity);
+    }
+
+    public void deleteProjectResourcesForProjectIdDirectly(Long localProjectId) {
+        db.getOcsProjectResourceDao().deleteByProjectId(localProjectId);
+    }
+
+    public void updateProjectDirectly(long accountId, OcsProject entity) {
+        entity.setAccountId(accountId);
+        db.getOcsProjectDao().update(entity);
+    }
+
+    public void deleteProjectDirectly(OcsProject ocsProject) {
+        db.getOcsProjectResourceDao().deleteByProjectId(ocsProject.getLocalId());
+        db.getOcsProjectDao().delete(ocsProject);
+    }
+
+    public Long createProjectResourceDirectly(Long accountId, OcsProjectResource resource) {
+        resource.setAccountId(accountId);
+        return db.getOcsProjectResourceDao().insert(resource);
+    }
+
+    public int countProjectResourcesInProjectDirectly(Long projectLocalId) {
+        return db.getOcsProjectResourceDao().countProjectResourcesInProjectDirectly(projectLocalId);
+    }
+
+    public LiveData<Integer> countProjectResourcesInProject(Long projectLocalId) {
+        return db.getOcsProjectResourceDao().countProjectResourcesInProject(projectLocalId);
+    }
+
+    public LiveData<List<OcsProjectResource>> getResourcesByLocalProjectId(Long projectLocalId) {
+        return db.getOcsProjectResourceDao().getResourcesByLocalProjectId(projectLocalId);
+    }
+
+    public void assignCardToProjectIfMissng(Long accountId, Long localProjectId, Long remoteCardId) {
+        Card card = db.getCardDao().getCardByRemoteIdDirectly(accountId, remoteCardId);
+        if (card != null) {
+            JoinCardWithProject existing = db.getJoinCardWithOcsProjectDao().getAssignmentByCardIdAndProjectIdDirectly(card.getLocalId(), localProjectId);
+            if (existing == null) {
+                JoinCardWithProject assignment = new JoinCardWithProject();
+                assignment.setStatus(DBStatus.UP_TO_DATE.getId());
+                assignment.setCardId(card.getLocalId());
+                assignment.setProjectId(localProjectId);
+                db.getJoinCardWithOcsProjectDao().insert(assignment);
+            }
+        }
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DateTypeConverter.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DateTypeConverter.java
index 6b198a502..f6811e033 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DateTypeConverter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DateTypeConverter.java
@@ -2,17 +2,17 @@ package it.niedermann.nextcloud.deck.persistence.sync.adapters.db;
 
 import androidx.room.TypeConverter;
 
-import java.util.Date;
+import java.time.Instant;
 
 public class DateTypeConverter {
 
     @TypeConverter
-    public static Date toDate(Long value) {
-        return value == null ? null : new Date(value);
+    public static Instant toInstant(Long value) {
+        return value == null ? null : Instant.ofEpochMilli(value);
     }
 
     @TypeConverter
-    public static Long toLong(Date value) {
-        return value == null ? null : value.getTime();
+    public static Long fromInstant(Instant value) {
+        return value == null ? null : value.toEpochMilli();
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DeckDatabase.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DeckDatabase.java
index 0e86557fa..a491946ed 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DeckDatabase.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/DeckDatabase.java
@@ -1,8 +1,11 @@
 package it.niedermann.nextcloud.deck.persistence.sync.adapters.db;
 
 import android.content.Context;
+import android.content.SharedPreferences;
 import android.database.Cursor;
+import android.graphics.Color;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.preference.PreferenceManager;
 import androidx.room.Database;
@@ -12,6 +15,7 @@ import androidx.room.TypeConverters;
 import androidx.room.migration.Migration;
 import androidx.sqlite.db.SupportSQLiteDatabase;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.LastSyncUtil;
 import it.niedermann.nextcloud.deck.model.AccessControl;
@@ -28,10 +32,16 @@ import it.niedermann.nextcloud.deck.model.Label;
 import it.niedermann.nextcloud.deck.model.Permission;
 import it.niedermann.nextcloud.deck.model.Stack;
 import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.model.appwidgets.StackWidgetModel;
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 import it.niedermann.nextcloud.deck.model.ocs.Activity;
 import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.Mention;
+import it.niedermann.nextcloud.deck.model.ocs.projects.JoinCardWithProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.model.relations.UserInBoard;
+import it.niedermann.nextcloud.deck.model.relations.UserInGroup;
 import it.niedermann.nextcloud.deck.model.widget.singlecard.SingleCardWidgetModel;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncWorker;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.AccessControlDao;
@@ -49,9 +59,15 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.JoinCardWit
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.LabelDao;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.MentionDao;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.PermissionDao;
-import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.SingleCardWidgetModelDao;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.StackDao;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.UserDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.UserInBoardDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.UserInGroupDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.projects.JoinCardWithOcsProjectDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.projects.OcsProjectDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.projects.OcsProjectResourceDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.SingleCardWidgetModelDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.StackWidgetModelDao;
 
 @Database(
         entities = {
@@ -73,9 +89,15 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.UserDao;
                 DeckComment.class,
                 Mention.class,
                 SingleCardWidgetModel.class,
+                StackWidgetModel.class,
+                OcsProject.class,
+                OcsProjectResource.class,
+                JoinCardWithProject.class,
+                UserInGroup.class,
+                UserInBoard.class,
         },
         exportSchema = false,
-        version = 15
+        version = 23
 )
 @TypeConverters({DateTypeConverter.class})
 public abstract class DeckDatabase extends RoomDatabase {
@@ -175,8 +197,204 @@ public abstract class DeckDatabase extends RoomDatabase {
         }
     };
 
-    public static final RoomDatabase.Callback ON_CREATE_CALLBACK = new RoomDatabase.Callback() {
+    private static final Migration MIGRATION_15_16 = new Migration(15, 16) {
+        @Override
+        public void migrate(SupportSQLiteDatabase database) {
+            database.execSQL("CREATE TABLE `StackWidgetModel` (`appWidgetId` INTEGER PRIMARY KEY, `accountId` INTEGER, `stackId` INTEGER, `darkTheme` INTEGER CHECK (`darkTheme` IN (0,1)) NOT NULL, " +
+                    "FOREIGN KEY(`accountId`) REFERENCES `Account`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE, " +
+                    "FOREIGN KEY(`stackId`) REFERENCES `Stack`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+            database.execSQL("CREATE INDEX `index_StackWidgetModel_stackId` ON `StackWidgetModel` (`stackId`)");
+            database.execSQL("CREATE INDEX `index_StackWidgetModel_accountId` ON `StackWidgetModel` (`accountId`)");
+        }
+    };
+
+    private static final Migration MIGRATION_16_17 = new Migration(16, 17) {
+        @Override
+        public void migrate(SupportSQLiteDatabase database) {
+            database.execSQL("CREATE TABLE `OcsProject` (`localId` INTEGER PRIMARY KEY AUTOINCREMENT, `accountId` INTEGER NOT NULL, `id` INTEGER, `name` TEXT NOT NULL, `status` INTEGER NOT NULL, `lastModified` INTEGER, `lastModifiedLocal` INTEGER)");
+            database.execSQL("CREATE UNIQUE INDEX `index_OcsProject_accountId_id` ON `OcsProject` (`accountId`, `id`)");
+            database.execSQL("CREATE INDEX `index_project_accID` ON `OcsProject` (`accountId`)");
+            database.execSQL("CREATE INDEX `index_OcsProject_id` ON `OcsProject` (`id`)");
+            database.execSQL("CREATE INDEX `index_OcsProject_lastModifiedLocal` ON `OcsProject` (`lastModifiedLocal`)");
+
+            database.execSQL("CREATE TABLE `OcsProjectResource` (`localId` INTEGER PRIMARY KEY AUTOINCREMENT, `accountId` INTEGER NOT NULL, `id` INTEGER, `name` TEXT, `status` INTEGER NOT NULL, `lastModified` INTEGER, `lastModifiedLocal` INTEGER, `projectId` INTEGER NOT NULL, `type` TEXT , `link` TEXT , `path` TEXT, `iconUrl` TEXT , `previewAvailable` INTEGER, `mimetype` TEXT, FOREIGN KEY(`projectId`) REFERENCES `OcsProject`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE)");
+            database.execSQL("CREATE INDEX `index_projectResource_accID` ON `OcsProjectResource` (`accountId`)");
+            database.execSQL("CREATE INDEX `index_projectResource_projectId` ON `OcsProjectResource` (`projectId`)");
+            database.execSQL("CREATE UNIQUE INDEX `index_OcsProjectResource_accountId_id` ON `OcsProjectResource` (`accountId`, `id`, `projectId`)");
+            database.execSQL("CREATE INDEX `index_OcsProjectResource_id` ON `OcsProjectResource` (`id`)");
+            database.execSQL("CREATE INDEX `index_OcsProjectResource_lastModifiedLocal` ON `OcsProjectResource` (`lastModifiedLocal`)");
+
+            database.execSQL("CREATE TABLE `JoinCardWithProject` (`status` INTEGER NOT NULL, `projectId` INTEGER NOT NULL, `cardId` INTEGER NOT NULL, PRIMARY KEY (`projectId`, `cardId`), FOREIGN KEY(`cardId`) REFERENCES `Card`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE, FOREIGN KEY(`projectId`) REFERENCES `OcsProject`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE)");
+            database.execSQL("CREATE INDEX `index_JoinCardWithProject_projectId` ON `JoinCardWithProject` (`projectId`)");
+            database.execSQL("CREATE INDEX `index_JoinCardWithProject_cardId` ON `JoinCardWithProject` (`cardId`)");
+        }
+    };
 
+    private static final Migration MIGRATION_17_18 = new Migration(17, 18) {
+        @Override
+        public void migrate(SupportSQLiteDatabase database) {
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/435
+            database.execSQL("ALTER TABLE `Account` ADD `etag` TEXT");
+        }
+    };
+    private static final Migration MIGRATION_18_19 = new Migration(18, 19) {
+        @Override
+        public void migrate(SupportSQLiteDatabase database) {
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/619
+            database.execSQL("DROP INDEX `index_OcsProjectResource_accountId_id`");
+            database.execSQL("ALTER TABLE `OcsProjectResource` ADD `idString` TEXT");
+            database.execSQL("CREATE UNIQUE INDEX `index_OcsProjectResource_accountId_id` ON `OcsProjectResource` (`accountId`, `id`, `idString`, `projectId`)");
+        }
+    };
+    private static final Migration MIGRATION_19_20 = new Migration(19, 20) {
+        @Override
+        public void migrate(SupportSQLiteDatabase database) {
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/492
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/631
+            database.execSQL("CREATE TABLE `UserInGroup` (`groupId` INTEGER NOT NULL, `memberId` INTEGER NOT NULL, " +
+                    "primary KEY(`groupId`, `memberId`), " +
+                    "FOREIGN KEY(`groupId`) REFERENCES `User`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE, " +
+                    "FOREIGN KEY(`memberId`) REFERENCES `User`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE)");
+            database.execSQL("CREATE UNIQUE INDEX `unique_idx_group_member` ON `UserInGroup` (`groupId`, `memberId`)");
+            database.execSQL("CREATE INDEX `index_UserInGroup_groupId` ON `UserInGroup` (`groupId`)");
+            database.execSQL("CREATE INDEX `index_UserInGroup_memberId` ON `UserInGroup` (`memberId`)");
+
+            database.execSQL("CREATE TABLE `UserInBoard` (`userId` INTEGER NOT NULL, `boardId` INTEGER NOT NULL, " +
+                    "primary KEY(`userId`, `boardId`), " +
+                    "FOREIGN KEY(`userId`) REFERENCES `User`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE, " +
+                    "FOREIGN KEY(`boardId`) REFERENCES `Board`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE)");
+            database.execSQL("CREATE UNIQUE INDEX `unique_idx_user_board` ON `UserInBoard` (`userId`, `boardId`)");
+            database.execSQL("CREATE INDEX `index_UserInBoard_userId` ON `UserInBoard` (`userId`)");
+            database.execSQL("CREATE INDEX `index_UserInBoard_boardId` ON `UserInBoard` (`boardId`)");
+        }
+    };
+
+    private static final Migration MIGRATION_20_21 = new Migration(20, 21) {
+        @Override
+        public void migrate(SupportSQLiteDatabase database) {
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/556
+            String suffix = "_new";
+            {
+                String tableName = "Account";
+                database.execSQL("CREATE TABLE `" + tableName + suffix + "` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `name` TEXT NOT NULL, `userName` TEXT NOT NULL, `url` TEXT NOT NULL, " +
+                        "`color` INTEGER NOT NULL DEFAULT 0, `textColor` INTEGER NOT NULL DEFAULT 0, `serverDeckVersion` TEXT NOT NULL DEFAULT '0.6.4', `maintenanceEnabled` INTEGER NOT NULL DEFAULT 0, `etag` TEXT)");
+                Cursor cursor = database.query("select * from `" + tableName + "`");
+                while (cursor.moveToNext()) {
+                    String colorAsString1 = cursor.getString(4); // color
+                    String colorAsString2 = cursor.getString(5); // textColor
+
+                    @ColorInt Integer color1 = null;
+                    @ColorInt Integer color2 = null;
+                    try {
+                        color1 = Color.parseColor(ColorUtil.INSTANCE.formatColorToParsableHexString(colorAsString1));
+                        color2 = Color.parseColor(ColorUtil.INSTANCE.formatColorToParsableHexString(colorAsString2));
+                    } catch (Exception e) {
+                        color1 = Color.GRAY;
+                        color2 = Color.GRAY;
+                    }
+                    database.execSQL("Insert into `" + tableName + suffix + "` VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)", new Object[]{
+                            cursor.getLong(0), cursor.getString(1), cursor.getString(2), cursor.getString(3),
+                            color1, color2, cursor.getString(6), cursor.getInt(7), cursor.getString(8)});
+
+                }
+
+
+                database.execSQL("DROP TABLE `" + tableName + "`");
+                database.execSQL("ALTER TABLE `" + tableName + suffix + "` RENAME TO `" + tableName + "`");
+                database.execSQL("CREATE UNIQUE INDEX `index_Account_name` ON `" + tableName + "` (`name`)");
+                database.execSQL("UPDATE SQLITE_SEQUENCE SET seq = (select max(id) from " + tableName + ") WHERE name = ?", new Object[]{tableName});
+            }
+            {
+                String tableName = "Board";
+                database.execSQL("CREATE TABLE `" + tableName + suffix + "` (`localId` INTEGER PRIMARY KEY AUTOINCREMENT, `accountId` INTEGER NOT NULL, `id` INTEGER, `status` INTEGER NOT NULL, " +
+                        "`lastModified` INTEGER, `lastModifiedLocal` INTEGER, `title` TEXT, `ownerId` INTEGER NOT NULL, `color` INTEGER, " +
+                        "`archived` INTEGER NOT NULL, `shared` INTEGER NOT NULL, `deletedAt` INTEGER, `permissionRead` INTEGER NOT NULL, " +
+                        "`permissionEdit` INTEGER NOT NULL, `permissionManage` INTEGER NOT NULL, `permissionShare` INTEGER NOT NULL, " +
+                        "FOREIGN KEY(`ownerId`) REFERENCES `User`(`localId`) ON UPDATE NO ACTION ON DELETE SET NULL )");
+                Cursor cursor = database.query("select * from `" + tableName + "`");
+                while (cursor.moveToNext()) {
+                    String colorAsString1 = cursor.getString(8); // color
+
+                    @ColorInt Integer color1 = null;
+                    try {
+                        color1 = Color.parseColor(ColorUtil.INSTANCE.formatColorToParsableHexString(colorAsString1));
+                    } catch (Exception e) {
+                        color1 = Color.GRAY;
+                    }
+                    database.execSQL("Insert into `" + tableName + suffix + "` VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)", new Object[]{
+                            cursor.getLong(0), cursor.getLong(1), cursor.getLong(2), cursor.getInt(3),
+                            cursor.getLong(4), cursor.getLong(5), cursor.getString(6), cursor.getLong(7), color1,
+                            cursor.getInt(9), cursor.getInt(10), cursor.getInt(11), cursor.getInt(12),
+                            cursor.getInt(13), cursor.getInt(14), cursor.getInt(15)
+                    });
+
+                }
+
+
+                database.execSQL("DROP TABLE `" + tableName + "`");
+                database.execSQL("ALTER TABLE `" + tableName + suffix + "` RENAME TO `" + tableName + "`");
+                database.execSQL("CREATE INDEX `index_Board_accountId` ON `" + tableName + "` (`accountId`)");
+                database.execSQL("CREATE UNIQUE INDEX `index_Board_accountId_id` ON `" + tableName + "` (`accountId`, `id`)");
+                database.execSQL("CREATE INDEX `index_Board_id` ON `" + tableName + "` (`id`)");
+                database.execSQL("CREATE INDEX `index_Board_ownerId` ON `" + tableName + "` (`ownerId`)");
+                database.execSQL("CREATE INDEX `index_Board_lastModifiedLocal` ON `" + tableName + "` (`lastModifiedLocal`)");
+                database.execSQL("UPDATE SQLITE_SEQUENCE SET seq = (select max(id) from " + tableName + ") WHERE name = ?", new Object[]{tableName});
+            }
+            {
+                String tableName = "Label";
+                database.execSQL("CREATE TABLE `" + tableName + suffix + "` (`localId` INTEGER PRIMARY KEY AUTOINCREMENT, `accountId` INTEGER NOT NULL, `id` INTEGER, `status` INTEGER NOT NULL, " +
+                        "`lastModified` INTEGER, `lastModifiedLocal` INTEGER, `title` TEXT, `color` INTEGER NOT NULL DEFAULT 0, `boardId` INTEGER NOT NULL, " +
+                        "FOREIGN KEY(`boardId`) REFERENCES `Board`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+                Cursor cursor = database.query("select * from `" + tableName + "`");
+                while (cursor.moveToNext()) {
+                    String colorAsString1 = cursor.getString(7); // color
+
+                    @ColorInt Integer color1 = null;
+                    try {
+                        color1 = Color.parseColor(ColorUtil.INSTANCE.formatColorToParsableHexString(colorAsString1));
+                    } catch (Exception e) {
+                        color1 = Color.GRAY;
+                    }
+                    database.execSQL("Insert into `" + tableName + suffix + "` VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)", new Object[]{
+                            cursor.getLong(0), cursor.getLong(1), cursor.getLong(2), cursor.getInt(3),
+                            cursor.getLong(4), cursor.getLong(5), cursor.getString(6), color1, cursor.getLong(8)});
+
+                }
+
+
+                database.execSQL("DROP TABLE `" + tableName + "`");
+                database.execSQL("ALTER TABLE `" + tableName + suffix + "` RENAME TO `" + tableName + "`");
+                database.execSQL("CREATE UNIQUE INDEX `index_Label_accountId_id` ON `" + tableName + "` (`accountId`, `id`)");
+                database.execSQL("CREATE INDEX `index_Label_boardId` ON `" + tableName + "` (`boardId`)");
+                database.execSQL("CREATE INDEX `index_Label_accountId` ON `" + tableName + "` (`accountId`)");
+                database.execSQL("CREATE UNIQUE INDEX `idx_label_title_unique` ON `" + tableName + "` (`boardId`, `title`)");
+                database.execSQL("CREATE INDEX `index_Label_id` ON `" + tableName + "` (`id`)");
+                database.execSQL("CREATE INDEX `index_Label_lastModifiedLocal` ON `" + tableName + "` (`lastModifiedLocal`)");
+                database.execSQL("UPDATE SQLITE_SEQUENCE SET seq = (select max(id) from " + tableName + ") WHERE name = ?", new Object[]{tableName});
+            }
+        }
+    };
+
+    private static final Migration MIGRATION_22_23 = new Migration(22, 23) {
+        @Override
+        public void migrate(SupportSQLiteDatabase database) {
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/359
+            database.execSQL("ALTER TABLE `Account` ADD `boardsEtag` TEXT");
+            database.execSQL("ALTER TABLE `Board` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Stack` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Card` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Label` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `AccessControl` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Attachment` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `User` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `DeckComment` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `Activity` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `OcsProject` ADD `etag` TEXT");
+            database.execSQL("ALTER TABLE `OcsProjectResource` ADD `etag` TEXT");
+        }
+    };
+
+    public static final RoomDatabase.Callback ON_CREATE_CALLBACK = new RoomDatabase.Callback() {
         @Override
         public void onCreate(@NonNull SupportSQLiteDatabase db) {
             super.onCreate(db);
@@ -216,6 +434,26 @@ public abstract class DeckDatabase extends RoomDatabase {
                                 .apply();
                     }
                 })
+                .addMigrations(MIGRATION_15_16)
+                .addMigrations(MIGRATION_16_17)
+                .addMigrations(MIGRATION_17_18)
+                .addMigrations(MIGRATION_18_19)
+                .addMigrations(MIGRATION_19_20)
+                .addMigrations(MIGRATION_20_21)
+                .addMigrations(new Migration(21, 22) {
+                    @Override
+                    public void migrate(@NonNull SupportSQLiteDatabase database) {
+                        // https://github.com/stefan-niedermann/nextcloud-deck/issues/715
+                        final SharedPreferences.Editor lastSyncPref = context.getApplicationContext().getSharedPreferences("it.niedermann.nextcloud.deck.last_sync", Context.MODE_PRIVATE).edit();
+                        Cursor cursor = database.query("select id from `Account`");
+                        while (cursor.moveToNext()) {
+                            lastSyncPref.remove("lS_" + cursor.getLong(0));
+                        }
+                        cursor.close();
+                        lastSyncPref.apply();
+                    }
+                })
+                .addMigrations(MIGRATION_22_23)
                 .fallbackToDestructiveMigration()
                 .addCallback(ON_CREATE_CALLBACK)
                 .build();
@@ -256,4 +494,16 @@ public abstract class DeckDatabase extends RoomDatabase {
     public abstract MentionDao getMentionDao();
 
     public abstract SingleCardWidgetModelDao getSingleCardWidgetModelDao();
+
+    public abstract StackWidgetModelDao getStackWidgetModelDao();
+
+    public abstract OcsProjectDao getOcsProjectDao();
+
+    public abstract OcsProjectResourceDao getOcsProjectResourceDao();
+
+    public abstract JoinCardWithOcsProjectDao getJoinCardWithOcsProjectDao();
+
+    public abstract UserInGroupDao getUserInGroupDao();
+
+    public abstract UserInBoardDao getUserInBoardDao();
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/AttachmentDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/AttachmentDao.java
index 2d0887903..8f7ee1cba 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/AttachmentDao.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/AttachmentDao.java
@@ -25,6 +25,10 @@ public interface AttachmentDao extends GenericDao<Attachment> {
     @Query("SELECT * FROM attachment WHERE accountId = :accountId and (status<>1 or id is null or lastModified <> lastModifiedLocal)")
     List<Attachment> getLocallyChangedAttachmentsDirectly(long accountId);
 
+    @Query("SELECT a.* FROM attachment a inner join card c on c.localId = a.cardId " +
+            "WHERE c.stackId = :localStackId and (a.status<>1 or a.id is null or a.lastModified <> a.lastModifiedLocal)")
+    List<Attachment> getLocallyChangedAttachmentsForStackDirectly(long localStackId);
+
     @Query("SELECT * FROM attachment WHERE accountId = :accountId and cardId = :localCardId")
     List<Attachment> getAttachmentsForLocalCardIdDirectly(long accountId, Long localCardId);
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/BoardDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/BoardDao.java
index bd189e846..6cb322aa3 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/BoardDao.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/BoardDao.java
@@ -13,6 +13,9 @@ import it.niedermann.nextcloud.deck.model.full.FullBoard;
 @Dao
 public interface BoardDao extends GenericDao<Board> {
 
+    @Query("SELECT * FROM board WHERE accountId = :accountId and (deletedAt = 0 or deletedAt is null) and status <> 3 order by title asc")
+    LiveData<List<Board>> getBoardsForAccount(final long accountId);
+
     @Query("SELECT * FROM board WHERE accountId = :accountId and archived = 1 and (deletedAt = 0 or deletedAt is null) and status <> 3 order by title asc")
     LiveData<List<Board>> getArchivedBoardsForAccount(final long accountId);
 
@@ -52,7 +55,8 @@ public interface BoardDao extends GenericDao<Board> {
     @Query("SELECT b.* FROM board b JOIN stack s ON s.boardId = b.localId JOIN card c ON c.localId = :localCardId")
     Board getBoardByLocalCardIdDirectly(long localCardId);
 
-    @Query("SELECT b.* FROM board b JOIN stack s ON s.boardId = b.localId JOIN card c ON c.localId = :localCardId")
+    @Transaction
+    @Query("SELECT b.* FROM board b JOIN stack s ON s.boardId = b.localId JOIN card c ON c.localId = :localCardId and c.stackId = s.localId")
     FullBoard getFullBoardByLocalCardIdDirectly(long localCardId);
 
     @Transaction
@@ -72,4 +76,7 @@ public interface BoardDao extends GenericDao<Board> {
 
     @Query("SELECT count(*) FROM board WHERE accountId = :accountId and archived = 1 and (deletedAt = 0 or deletedAt is null) and status <> 3")
     LiveData<Integer> countArchivedBoards(long accountId);
+
+    @Query("SELECT * FROM board WHERE accountId = :accountId and title = :title")
+    Board getBoardForAccountByNameDirectly(long accountId, String title);
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/CardDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/CardDao.java
index 57163112a..82bdf1b8d 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/CardDao.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/CardDao.java
@@ -11,6 +11,7 @@ import java.util.List;
 
 import it.niedermann.nextcloud.deck.model.Card;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.model.full.FullCardWithProjects;
 
 @Dao
 public interface CardDao extends GenericDao<Card> {
@@ -36,17 +37,24 @@ public interface CardDao extends GenericDao<Card> {
     @Query("SELECT * FROM card WHERE accountId = :accountId AND archived = 0 AND stackId = :localStackId and status<>3 order by `order`, createdAt asc")
     LiveData<List<FullCard>> getFullCardsForStack(final long accountId, final long localStackId);
 
-    @Transaction                                                                                // v not deleted!
+    @Transaction
     @RawQuery(observedEntities = Card.class)
     LiveData<List<FullCard>> getFilteredFullCardsForStack(SupportSQLiteQuery query);
 
     @Transaction
+    @RawQuery(observedEntities = Card.class)
+    List<FullCard> getFilteredFullCardsForStackDirectly(SupportSQLiteQuery query);
+
+    @Transaction
     @Query("SELECT * FROM card WHERE accountId = :accountId AND stackId = :localStackId order by `order`, createdAt asc")
     List<FullCard> getFullCardsForStackDirectly(final long accountId, final long localStackId);
 
     @Transaction
     @Query("SELECT * FROM card WHERE accountId = :accountId and localId = :localCardId")
     LiveData<FullCard> getFullCardByLocalId(final long accountId, final long localCardId);
+    @Transaction
+    @Query("SELECT * FROM card WHERE accountId = :accountId and localId = :localCardId")
+    LiveData<FullCardWithProjects> getFullCardWithProjectsByLocalId(final long accountId, final long localCardId);
 
     @Transaction
     @Query("SELECT * FROM card WHERE accountId = :accountId and id = :remoteId")
@@ -66,9 +74,15 @@ public interface CardDao extends GenericDao<Card> {
     @Query("SELECT * FROM card c WHERE accountId = :accountId and exists ( select 1 from DeckComment dc where dc.objectId = c.localId and dc.status<>1)")
     List<Card> getCardsWithLocallyChangedCommentsDirectly(Long accountId);
 
+    @Query("SELECT * FROM card c WHERE stackId = :localStackId and exists ( select 1 from DeckComment dc where dc.objectId = c.localId and dc.status<>1)")
+    List<Card> getCardsWithLocallyChangedCommentsForStackDirectly(Long localStackId);
+
     @Query("SELECT count(*) FROM card c WHERE accountId = :accountId and stackId = :localStackId and status <> 3")
     LiveData<Integer> countCardsInStack(long accountId, long localStackId);
 
     @Query("SELECT coalesce(MAX(`order`), -1) FROM card c WHERE  stackId = :localStackId and status <> 3")
     Integer getHighestOrderInStack(Long localStackId);
+
+    @Query("SELECT c.stackId FROM card c WHERE  localId = :localCardId")
+    Long getLocalStackIdByLocalCardId(Long localCardId);
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/JoinCardWithLabelDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/JoinCardWithLabelDao.java
index c96c64e7d..26e6c65a8 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/JoinCardWithLabelDao.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/JoinCardWithLabelDao.java
@@ -40,6 +40,9 @@ public interface JoinCardWithLabelDao extends GenericDao<JoinCardWithLabel> {
     @Query("select * from joincardwithlabel WHERE status <> 1") // not UP_TO_DATE
     List<JoinCardWithLabel> getAllChangedJoins();
 
+    @Query("select j.* from joincardwithlabel j inner join card c on j.cardId = c.localId  WHERE c.stackId = :localStackId and j.status <> 1") // not UP_TO_DATE
+    List<JoinCardWithLabel> getAllChangedJoinsForStack(Long localStackId);
+
     @Query("delete from joincardwithlabel " +
             "where cardId = (select c.localId from card c where c.accountId = :accountId and c.id = :remoteCardId) " +
             "and labelId = (select l.localId from label l where l.accountId = :accountId and l.id = :remoteLabelId)")
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/JoinCardWithUserDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/JoinCardWithUserDao.java
index 46554685f..416d52eed 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/JoinCardWithUserDao.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/JoinCardWithUserDao.java
@@ -25,7 +25,14 @@ public interface JoinCardWithUserDao extends GenericDao<JoinCardWithUser> {
             "inner join card c on j.cardId = c.localId " +
             "inner join user u on j.userId = u.localId " +
             "WHERE j.status <> 1") // not UP_TO_DATE
-    List<JoinCardWithUser> getDeletedJoinsWithRemoteIDs();
+    List<JoinCardWithUser> getChangedJoinsWithRemoteIDs();
+
+    @Query("select u.localId as userId, c.id as cardId, j.status from joincardwithuser j " +
+            "inner join card c on j.cardId = c.localId " +
+            "inner join user u on j.userId = u.localId " +
+            "WHERE c.stackId = :localStackId " +
+            "AND j.status <> 1") // not UP_TO_DATE
+    List<JoinCardWithUser> getChangedJoinsWithRemoteIDsForStack(Long localStackId);
 
     @Query("delete from joincardwithuser " +
             "where cardId = (select c.localId from card c where c.accountId = :accountId and c.id = :remoteCardId) " +
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/StackDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/StackDao.java
index 0fbccbe08..feb7e453b 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/StackDao.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/StackDao.java
@@ -13,7 +13,7 @@ import it.niedermann.nextcloud.deck.model.full.FullStack;
 @Dao
 public interface StackDao extends GenericDao<Stack> {
 
-    @Query("SELECT * FROM stack WHERE accountId = :accountId AND boardId = :localBoardId order by `order` asc")
+    @Query("SELECT * FROM stack WHERE accountId = :accountId AND boardId = :localBoardId and status<>3 and (deletedAt is null or deletedAt = 0) order by `order` asc")
     LiveData<List<Stack>> getStacksForBoard(final long accountId, final long localBoardId);
 
     @Query("SELECT * FROM stack WHERE accountId = :accountId and boardId = :localBoardId and id = :remoteId")
@@ -31,10 +31,6 @@ public interface StackDao extends GenericDao<Stack> {
     FullStack getFullStackByRemoteIdDirectly(final long accountId, final long localBoardId, final long remoteId);
 
     @Transaction
-    @Query("SELECT * FROM stack WHERE accountId = :accountId AND boardId = :localBoardId and status<>3 and (deletedAt is null or deletedAt = 0) order by `order` asc")
-    LiveData<List<FullStack>> getFullStacksForBoard(final long accountId, final long localBoardId);
-
-    @Transaction
     @Query("SELECT * FROM stack WHERE accountId = :accountId and boardId = :localBoardId and id = :remoteId")
     LiveData<FullStack> getFullStackByRemoteId(final long accountId, final long localBoardId, final long remoteId);
 
@@ -56,4 +52,7 @@ public interface StackDao extends GenericDao<Stack> {
 
     @Query("SELECT localId FROM stack s WHERE accountId = :accountId and id = :stackId")
     Long getLocalStackIdByRemoteStackIdDirectly(long accountId, Long stackId);
+
+    @Query("SELECT coalesce(MAX(`order`), -1) FROM stack s WHERE boardId = :localBoardId")
+    Integer getHighestStackOrderInBoard(long localBoardId);
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserDao.java
index 6f712d07f..6e42cdaae 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserDao.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserDao.java
@@ -26,12 +26,16 @@ public interface UserDao extends GenericDao<User> {
             "            where ju.userId = u.localId" +
             "            and ju.cardId = :notYetAssignedToLocalCardId AND status <> 3" + // not LOCAL_DELETED
             "    )" +
-            "    AND" +
-            "            (" +
-            "                    EXISTS (" +
-            "                    select 1 from accesscontrol" +
-            "                    where userId = u.localId and boardId = :boardId" +
-            "            )" +
+            "  AND ( " +
+            "    EXISTS (" +
+            "            select 1 from userinboard where boardId = :boardId AND userId = u.localId" +
+            "    )" +
+            "    OR" +
+            "    EXISTS (" +
+            "       select 1 from accesscontrol" + //  v GROUP!
+            "       where (userId = u.localId OR (type = 1 and exists(select 1 from UserInGroup uig where uig.memberId = u.localId and uig.groupId = userId))) " +
+            "           and boardId = :boardId and status <> 3" +
+            "    )" +
             "    OR" +
             "    EXISTS (" +
             "            select 1 from board where localId = :boardId AND ownerId = u.localId" +
@@ -48,7 +52,7 @@ public interface UserDao extends GenericDao<User> {
             "and ( uid LIKE :searchTerm or displayname LIKE :searchTerm or primaryKey LIKE :searchTerm ) " +
             "and u.localId <> (select b.ownerId from board b where localId = :boardId)" +
             "ORDER BY u.displayname")
-    LiveData<List<User>> searchUserByUidOrDisplayNameForACL(final long accountId, final long boardId, final String searchTerm);
+    List<User> searchUserByUidOrDisplayNameForACLDirectly(final long accountId, final long boardId, final String searchTerm);
 
     @Query("SELECT * FROM user WHERE accountId = :accountId and uid = :uid")
     User getUserByUidDirectly(final long accountId, final String uid);
@@ -66,12 +70,16 @@ public interface UserDao extends GenericDao<User> {
             "            where ju.userId = u.localId" +
             "            and ju.cardId = :notAssignedToLocalCardId AND status <> 3" + // not LOCAL_DELETED
             "    )" +
-            "    AND" +
-            "            (" +
-            "                    EXISTS (" +
-            "                    select 1 from accesscontrol" +
-            "                    where userId = u.localId and boardId = :boardId" +
-            "            )" +
+            "  AND ( " +
+            "    EXISTS (" +
+            "            select 1 from userinboard where boardId = :boardId AND userId = u.localId" +
+            "    )" +
+            "    OR" +
+            "    EXISTS (" +
+            "       select 1 from accesscontrol" + //  v GROUP!
+            "       where (userId = u.localId OR (type = 1 and exists(select 1 from UserInGroup uig where uig.memberId = u.localId and uig.groupId = userId))) " +
+            "           and boardId = :boardId and status <> 3" +
+            "    )" +
             "    OR" +
             "    EXISTS (" +
             "            select 1 from board where localId = :boardId AND ownerId = u.localId" +
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserInBoardDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserInBoardDao.java
new file mode 100644
index 000000000..7a0476c53
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserInBoardDao.java
@@ -0,0 +1,12 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import it.niedermann.nextcloud.deck.model.relations.UserInBoard;
+
+@Dao
+public interface UserInBoardDao extends GenericDao<UserInBoard> {
+    @Query("DELETE FROM userinboard WHERE boardId = :localId")
+    void deleteByBoardId(long localId);
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserInGroupDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserInGroupDao.java
new file mode 100644
index 000000000..fb3f5b26e
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/UserInGroupDao.java
@@ -0,0 +1,12 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import it.niedermann.nextcloud.deck.model.relations.UserInGroup;
+
+@Dao
+public interface UserInGroupDao extends GenericDao<UserInGroup> {
+    @Query("DELETE FROM useringroup WHERE groupId = :localId")
+    void deleteByGroupId(long localId);
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/projects/JoinCardWithOcsProjectDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/projects/JoinCardWithOcsProjectDao.java
new file mode 100644
index 000000000..d132796e4
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/projects/JoinCardWithOcsProjectDao.java
@@ -0,0 +1,13 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.projects;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import it.niedermann.nextcloud.deck.model.ocs.projects.JoinCardWithProject;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface JoinCardWithOcsProjectDao extends GenericDao<JoinCardWithProject> {
+    @Query("select * from JoinCardWithProject where projectId = :localProjectId and cardId = :localCardId")
+    JoinCardWithProject getAssignmentByCardIdAndProjectIdDirectly(Long localCardId, Long localProjectId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/projects/OcsProjectDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/projects/OcsProjectDao.java
new file mode 100644
index 000000000..fb0e3f836
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/projects/OcsProjectDao.java
@@ -0,0 +1,13 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.projects;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProject;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface OcsProjectDao  extends GenericDao<OcsProject> {
+    @Query("select * from OcsProject where accountId = :accountId and id = :remoteId")
+    OcsProject getProjectByRemoteIdDirectly(long accountId, Long remoteId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/projects/OcsProjectResourceDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/projects/OcsProjectResourceDao.java
new file mode 100644
index 000000000..8a544667a
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/projects/OcsProjectResourceDao.java
@@ -0,0 +1,25 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.projects;
+
+import androidx.lifecycle.LiveData;
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface OcsProjectResourceDao extends GenericDao<OcsProjectResource> {
+    @Query("delete from OcsProjectResource where projectId = :localProjectId")
+    void deleteByProjectId(Long localProjectId);
+
+    @Query("select * from OcsProjectResource where projectId = :localProjectId")
+    LiveData<List<OcsProjectResource>> getResourcesByLocalProjectId(Long localProjectId);
+
+    @Query("select count(id) from OcsProjectResource where projectId = :localProjectId")
+    int countProjectResourcesInProjectDirectly(Long localProjectId);
+
+    @Query("select count(id) from OcsProjectResource where projectId = :localProjectId")
+    LiveData<Integer> countProjectResourcesInProject(Long localProjectId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/SingleCardWidgetModelDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/SingleCardWidgetModelDao.java
index 0c2a485c1..a26269c30 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/SingleCardWidgetModelDao.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/SingleCardWidgetModelDao.java
@@ -1,4 +1,4 @@
-package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao;
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets;
 
 import androidx.room.Dao;
 import androidx.room.Query;
@@ -6,6 +6,7 @@ import androidx.room.Transaction;
 
 import it.niedermann.nextcloud.deck.model.full.FullSingleCardWidgetModel;
 import it.niedermann.nextcloud.deck.model.widget.singlecard.SingleCardWidgetModel;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
 
 @Dao
 public interface SingleCardWidgetModelDao extends GenericDao<SingleCardWidgetModel> {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/StackWidgetModelDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/StackWidgetModelDao.java
new file mode 100644
index 000000000..9b370e32b
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/StackWidgetModelDao.java
@@ -0,0 +1,19 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+import androidx.room.Transaction;
+
+import it.niedermann.nextcloud.deck.model.appwidgets.StackWidgetModel;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface StackWidgetModelDao extends GenericDao<StackWidgetModel> {
+
+    @Query("SELECT * FROM stackwidgetmodel WHERE appwidgetid = :appWidgetId")
+    StackWidgetModel getStackWidgetByAppWidgetIdDirectly(final int appWidgetId);
+
+    @Transaction
+    @Query("SELECT EXISTS (SELECT 1 FROM stackwidgetmodel WHERE stackId in (:stackLocalIds))")
+    boolean containsStackLocalId(final long... stackLocalIds);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/WrappedLiveData.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/WrappedLiveData.java
index 038fcbad8..003bceb26 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/WrappedLiveData.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/WrappedLiveData.java
@@ -1,5 +1,6 @@
 package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.lifecycle.MutableLiveData;
 
@@ -28,10 +29,13 @@ public class WrappedLiveData<T> extends MutableLiveData<T> {
     }
 
     public void postError(@Nullable Throwable error) {
+        postError(error, null);
+    }
+    public void postError(@Nullable Throwable error, @NonNull T locallyCreatedEntity) {
         if (error == null) {
             DeckLog.warn("Given error is null");
         }
         setError(error);
-        postValue(null);
+        postValue(locallyCreatedEntity);
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/extrawurst/Debouncer.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/extrawurst/Debouncer.java
new file mode 100644
index 000000000..fca4ca369
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/extrawurst/Debouncer.java
@@ -0,0 +1,75 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.extrawurst;
+
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+public class Debouncer <T> {
+  private final ScheduledExecutorService sched = Executors.newScheduledThreadPool(1);
+  private final ConcurrentHashMap<T, TimerTask> delayedMap = new ConcurrentHashMap<T, TimerTask>();
+  private final Callback<T> callback;
+  private final int interval;
+
+  public Debouncer(Callback<T> c, int interval) {
+    this.callback = c;
+    this.interval = interval;
+  }
+
+  public void call(T key) {
+    TimerTask task = new TimerTask(key);
+
+    TimerTask prev;
+    do {
+      prev = delayedMap.putIfAbsent(key, task);
+      if (prev == null)
+        sched.schedule(task, interval, TimeUnit.MILLISECONDS);
+      // Exit only if new task was added to map, or existing task was extended successfully
+    } while (prev != null && !prev.extend());
+  }
+
+  public void terminate() {
+    sched.shutdownNow();
+  }
+
+  public interface Callback<T> {
+    void call(T key);
+  }
+
+  // The task that wakes up when the wait time elapses
+  private class TimerTask implements Runnable {
+    private final T key;
+    private long dueTime;
+    private final Object lock = new Object();
+
+    public TimerTask(T key) {
+      this.key = key;
+      extend();
+    }
+
+    public boolean extend() {
+      synchronized (lock) {
+        if (dueTime < 0) // Task has been shutdown
+          return false;
+        dueTime = System.currentTimeMillis() + interval;
+        return true;
+      }
+    }
+
+    public void run() {
+      synchronized (lock) {
+        long remaining = dueTime - System.currentTimeMillis();
+        if (remaining > 0) { // Re-schedule task
+          sched.schedule(this, remaining, TimeUnit.MILLISECONDS);
+        } else { // Mark as terminated and invoke callback
+          dueTime = -1;
+          try {
+            callback.call(key);
+          } finally {
+            delayedMap.remove(key);
+          }
+        }
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/extrawurst/UserSearchLiveData.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/extrawurst/UserSearchLiveData.java
new file mode 100644
index 000000000..179d816eb
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/util/extrawurst/UserSearchLiveData.java
@@ -0,0 +1,93 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.extrawurst;
+
+import androidx.lifecycle.MediatorLiveData;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.exceptions.OfflineException;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.model.enums.DBStatus;
+import it.niedermann.nextcloud.deck.model.ocs.user.OcsUser;
+import it.niedermann.nextcloud.deck.model.ocs.user.OcsUserList;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
+
+public class UserSearchLiveData extends MediatorLiveData<List<User>> implements Debouncer.Callback<Long> {
+
+    private static final int DEBOUNCE_TIME = 300; // ms
+    private DataBaseAdapter db;
+    private ServerAdapter server;
+    long accountId;
+    String searchTerm;
+    long notYetAssignedInACL;
+    private Debouncer<Long> debouncer = new Debouncer<>(this, DEBOUNCE_TIME);
+
+    public UserSearchLiveData(DataBaseAdapter db, ServerAdapter server) {
+        this.db = db;
+        this.server = server;
+    }
+
+    public UserSearchLiveData search(long accountId, long notYetAssignedInACL, String searchTerm) {
+        this.accountId = accountId;
+        this.searchTerm = searchTerm;
+        this.notYetAssignedInACL = notYetAssignedInACL;
+        new Thread(() -> debouncer.call(notYetAssignedInACL)).start();
+        return this;
+    }
+
+
+    @Override
+    public void call(Long key) {
+        if (key!=notYetAssignedInACL){
+            return;
+        }
+
+        final String term = String.copyValueOf(searchTerm.toCharArray());
+
+        postCurrentFromDB(term);
+
+        if (server.hasInternetConnection()) {
+            try {
+                Account account = db.getAccountByIdDirectly(accountId);
+                server.searchUser(term, new IResponseCallback<OcsUserList>(account) {
+                    @Override
+                    public void onResponse(OcsUserList response) {
+                        if (response == null || response.getUsers().isEmpty()){
+                            return;
+                        }
+                        for (OcsUser user : response.getUsers()) {
+                            User existingUser = db.getUserByUidDirectly(accountId, user.getId());
+                            if (existingUser == null) {
+                                User newUser = new User();
+                                newUser.setStatus(DBStatus.UP_TO_DATE.getId());
+                                newUser.setPrimaryKey(user.getId());
+                                newUser.setUid(user.getId());
+                                newUser.setDisplayname(user.getDisplayName());
+                                db.createUser(accountId, newUser);
+                            }
+                        }
+                        if (!term.equals(searchTerm)) {
+                            return;
+                        }
+                        postCurrentFromDB(term);
+                    }
+
+                    @Override
+                    public void onError(Throwable throwable) {
+                        super.onError(throwable);
+                    }
+                });
+            } catch (OfflineException e) {
+                DeckLog.logError(e);
+            }
+        }
+    }
+
+    private void postCurrentFromDB(String term) {
+        List<User> foundInDB = db.searchUserByUidOrDisplayNameForACLDirectly(accountId, notYetAssignedInACL, term);
+        postValue(foundInDB);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/DataPropagationHelper.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/DataPropagationHelper.java
index 9590f5abd..782b6d951 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/DataPropagationHelper.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/DataPropagationHelper.java
@@ -34,27 +34,31 @@ public class DataPropagationHelper {
         entity.setLocalId(newID);
         boolean connected = serverAdapter.hasInternetConnection();
         if (connected) {
-            provider.createOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(new Account(accountId)) {
-                @Override
-                public void onResponse(T response) {
-                    new Thread(() -> {
-                        response.setAccountId(accountId);
-                        response.setLocalId(newID);
-                        if (actionOnResponse!= null) {
-                            actionOnResponse.onResponse(entity, response);
-                        }
-                        response.setStatus(DBStatus.UP_TO_DATE.getId());
-                        provider.updateInDB(dataBaseAdapter, accountId, response, false);
-                        callback.onResponse(response);
-                    }).start();
-                }
+            try {
+                provider.createOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(new Account(accountId)) {
+                    @Override
+                    public void onResponse(T response) {
+                        new Thread(() -> {
+                            response.setAccountId(accountId);
+                            response.setLocalId(newID);
+                            if (actionOnResponse != null) {
+                                actionOnResponse.onResponse(entity, response);
+                            }
+                            response.setStatus(DBStatus.UP_TO_DATE.getId());
+                            provider.updateInDB(dataBaseAdapter, accountId, response, false);
+                            callback.onResponse(response);
+                        }).start();
+                    }
 
-                @Override
-                public void onError(Throwable throwable) {
-                    super.onError(throwable);
-                    new Thread(() -> callback.onError(throwable)).start();
-                }
-            }, entity);
+                    @Override
+                    public void onError(Throwable throwable) {
+                        super.onError(throwable);
+                        new Thread(() -> callback.onError(throwable, entity)).start();
+                    }
+                }, entity);
+            } catch (Throwable t) {
+                callback.onError(t, entity);
+            }
         } else {
             callback.onResponse(entity);
         }
@@ -71,24 +75,28 @@ public class DataPropagationHelper {
         }
         boolean connected = serverAdapter.hasInternetConnection();
         if (entity.getId() != null && connected) {
-            provider.updateOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(new Account(accountId)) {
-                @Override
-                public void onResponse(T response) {
-                    new Thread(() -> {
-                        entity.setStatus(DBStatus.UP_TO_DATE.getId());
-                        provider.updateInDB(dataBaseAdapter, accountId, entity, false);
-                        callback.onResponse(entity);
-                    }).start();
-                }
+            try {
+                provider.updateOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(new Account(accountId)) {
+                    @Override
+                    public void onResponse(T response) {
+                        new Thread(() -> {
+                            entity.setStatus(DBStatus.UP_TO_DATE.getId());
+                            provider.updateInDB(dataBaseAdapter, accountId, entity, false);
+                            callback.onResponse(entity);
+                        }).start();
+                    }
 
-                @Override
-                public void onError(Throwable throwable) {
-                    super.onError(throwable);
-                    new Thread(() -> {
-                        callback.onError(throwable);
-                    }).start();
-                }
-            }, entity);
+                    @Override
+                    public void onError(Throwable throwable) {
+                        super.onError(throwable);
+                        new Thread(() -> {
+                            callback.onError(throwable, entity);
+                        }).start();
+                    }
+                }, entity);
+            } catch (Throwable t) {
+                callback.onError(t, entity);
+            }
         } else {
             callback.onResponse(entity);
         }
@@ -98,23 +106,28 @@ public class DataPropagationHelper {
         provider.deleteInDB(dataBaseAdapter, accountId, entity);
         boolean connected = serverAdapter.hasInternetConnection();
         if (entity.getId() != null && connected) {
-            provider.deleteOnServer(serverAdapter, accountId, new IResponseCallback<Void>(new Account(accountId)) {
-                @Override
-                public void onResponse(Void response) {
-                    new Thread(() -> {
-                        provider.deletePhysicallyInDB(dataBaseAdapter, accountId, entity);
-                        callback.onResponse(null);
-                    }).start();
-                }
+            try {
+                provider.deleteOnServer(serverAdapter, accountId, new IResponseCallback<Void>(new Account(accountId)) {
+                    @Override
+                    public void onResponse(Void response) {
+                        new Thread(() -> {
+                            provider.deletePhysicallyInDB(dataBaseAdapter, accountId, entity);
+                            callback.onResponse(null);
+                        }).start();
+                    }
+
+                    @Override
+                    public void onError(Throwable throwable) {
+                        super.onError(throwable);
+                        new Thread(() -> {
+                            callback.onError(throwable);
+                        }).start();
+                    }
+                }, entity, dataBaseAdapter);
+            } catch (Throwable t) {
+                callback.onError(t);
+            }
 
-                @Override
-                public void onError(Throwable throwable) {
-                    super.onError(throwable);
-                    new Thread(() -> {
-                        callback.onError(throwable);
-                    }).start();
-                }
-            }, entity, dataBaseAdapter);
         } else {
             callback.onResponse(null);
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/SyncHelper.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/SyncHelper.java
index 18d8c3672..17c0de2cf 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/SyncHelper.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/SyncHelper.java
@@ -1,6 +1,12 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers;
 
-import java.util.Date;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
+
+import java.net.HttpURLConnection;
+import java.time.Instant;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 
@@ -15,28 +21,33 @@ import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.AbstractS
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.IRelationshipProvider;
 
 public class SyncHelper {
-    private ServerAdapter serverAdapter;
-    private DataBaseAdapter dataBaseAdapter;
+    private final ServerAdapter serverAdapter;
+    private final DataBaseAdapter dataBaseAdapter;
     private Account account;
     private long accountId;
     private IResponseCallback<Boolean> responseCallback;
-    private Date lastSync;
+    private final Instant lastSync;
 
-    public SyncHelper(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, Date lastSync) {
+    public SyncHelper(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, Instant lastSync) {
         this.serverAdapter = serverAdapter;
         this.dataBaseAdapter = dataBaseAdapter;
         this.lastSync = lastSync;
     }
 
     // Sync Server -> App
-    public <T extends IRemoteEntity> void  doSyncFor(final AbstractSyncDataProvider<T> provider){
+    public <T extends IRemoteEntity> void doSyncFor(@NonNull final AbstractSyncDataProvider<T> provider) {
         provider.registerChildInParent(provider);
-        provider.getAllFromServer(serverAdapter, accountId, new IResponseCallback<List<T>>(account) {
+        provider.getAllFromServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<List<T>>(account) {
             @Override
             public void onResponse(List<T> response) {
                 if (response != null) {
                     provider.goingDeeper();
                     for (T entityFromServer : response) {
+                        if (entityFromServer == null) {
+                            // see https://github.com/stefan-niedermann/nextcloud-deck/issues/574
+                            DeckLog.error("Skipped null value from server for DataProvider: " + provider.getClass().getSimpleName());
+                            continue;
+                        }
                         entityFromServer.setAccountId(accountId);
                         T existingEntity = provider.getSingleFromDB(dataBaseAdapter, accountId, entityFromServer);
 
@@ -44,13 +55,14 @@ public class SyncHelper {
                             provider.createInDB(dataBaseAdapter, accountId, entityFromServer);
                         } else {
                             //TODO: how to handle deletes? what about archived?
-                            if (existingEntity.getStatus() != DBStatus.UP_TO_DATE.getId()){
-                                DeckLog.log("Conflicting changes on entity: "+existingEntity);
+                            if (existingEntity.getStatus() != DBStatus.UP_TO_DATE.getId()) {
+                                DeckLog.warn("Conflicting changes on entity: " + existingEntity);
                                 // TODO: what to do?
                             } else {
-//                                if (existingEntity.getLastModified().getTime() == entityFromServer.getLastModified().getTime()) {
-//                                    continue; // TODO: is this is ok for sure? -> isn`t! NPE
-//                                }
+                                if (entityFromServer.getEtag() != null && entityFromServer.getEtag().equals(existingEntity.getEtag())) {
+                                    DeckLog.log("[" + provider.getClass().getSimpleName() + "] ETags do match! skipping " + existingEntity.getClass().getSimpleName() + " with localId: " + existingEntity.getLocalId());
+                                    continue;
+                                }
                                 provider.updateInDB(dataBaseAdapter, accountId, applyUpdatesFromRemote(provider, existingEntity, entityFromServer, accountId), false);
                             }
                         }
@@ -58,7 +70,7 @@ public class SyncHelper {
                         provider.goDeeper(SyncHelper.this, existingEntity, entityFromServer, responseCallback);
                     }
 
-                     provider.handleDeletes(serverAdapter, dataBaseAdapter, accountId, response);
+                    provider.handleDeletes(serverAdapter, dataBaseAdapter, accountId, response);
 
                     provider.doneGoingDeeper(responseCallback, true);
                 } else {
@@ -68,25 +80,35 @@ public class SyncHelper {
 
             @Override
             public void onError(Throwable throwable) {
+                super.onError(throwable);
+                if (throwable.getClass() == NextcloudHttpRequestFailedException.class) {
+                    NextcloudHttpRequestFailedException requestFailedException = (NextcloudHttpRequestFailedException) throwable;
+                    if (HttpURLConnection.HTTP_NOT_MODIFIED == requestFailedException.getStatusCode()){
+                        DeckLog.log("[" + provider.getClass().getSimpleName() + "] ETags do match! skipping this one.");
+                        // well, etags say we're fine here. no need to go deeper.
+                        provider.childDone(provider, responseCallback, false);
+                        return;
+                    }
+                }
                 provider.onError(throwable, responseCallback);
-                DeckLog.logError(throwable);
                 responseCallback.onError(throwable);
             }
         }, lastSync);
     }
 
     // Sync App -> Server
-    public <T extends IRemoteEntity> void doUpSyncFor(AbstractSyncDataProvider<T> provider){
+    public <T extends IRemoteEntity> void doUpSyncFor(@NonNull AbstractSyncDataProvider<T> provider) {
         doUpSyncFor(provider, null);
     }
-    public <T extends IRemoteEntity> void doUpSyncFor(AbstractSyncDataProvider<T> provider, CountDownLatch countDownLatch){
-        List<T> allFromDB = provider.getAllChangedFromDB(dataBaseAdapter, accountId, lastSync);
+
+    public <T extends IRemoteEntity> void doUpSyncFor(@NonNull AbstractSyncDataProvider<T> provider, @Nullable CountDownLatch countDownLatch) {
+        final List<T> allFromDB = provider.getAllChangedFromDB(dataBaseAdapter, accountId, lastSync);
         if (allFromDB != null && !allFromDB.isEmpty()) {
             for (T entity : allFromDB) {
-                if (entity.getId()!=null) {
+                if (entity.getId() != null) {
                     if (entity.getStatusEnum() == DBStatus.LOCAL_DELETED) {
                         provider.deleteOnServer(serverAdapter, accountId, getDeleteCallback(provider, entity), entity, dataBaseAdapter);
-                        if (countDownLatch != null){
+                        if (countDownLatch != null) {
                             countDownLatch.countDown();
                         }
                     } else {
@@ -98,13 +120,13 @@ public class SyncHelper {
             }
         } else {
             provider.goDeeperForUpSync(this, serverAdapter, dataBaseAdapter, responseCallback);
-            if (countDownLatch != null){
+            if (countDownLatch != null) {
                 countDownLatch.countDown();
             }
         }
     }
 
-    private <T extends IRemoteEntity> IResponseCallback<Void> getDeleteCallback(AbstractSyncDataProvider<T> provider, T entity) {
+    private <T extends IRemoteEntity> IResponseCallback<Void> getDeleteCallback(@NonNull AbstractSyncDataProvider<T> provider, T entity) {
         return new IResponseCallback<Void>(account) {
             @Override
             public void onResponse(Void response) {
@@ -120,16 +142,17 @@ public class SyncHelper {
         };
     }
 
-    private <T extends IRemoteEntity> IResponseCallback<T> getUpdateCallback(AbstractSyncDataProvider<T> provider, T entity, CountDownLatch countDownLatch) {
+    private <T extends IRemoteEntity> IResponseCallback<T> getUpdateCallback(@NonNull AbstractSyncDataProvider<T> provider, @NonNull T entity, @Nullable CountDownLatch countDownLatch) {
         return new IResponseCallback<T>(account) {
             @Override
             public void onResponse(T response) {
                 response.setAccountId(this.account.getId());
                 T update = applyUpdatesFromRemote(provider, entity, response, accountId);
+                update.setId(response.getId());
                 update.setStatus(DBStatus.UP_TO_DATE.getId());
                 provider.updateInDB(dataBaseAdapter, accountId, update, false);
                 provider.goDeeperForUpSync(SyncHelper.this, serverAdapter, dataBaseAdapter, responseCallback);
-                if (countDownLatch != null){
+                if (countDownLatch != null) {
                     countDownLatch.countDown();
                 }
             }
@@ -138,20 +161,20 @@ public class SyncHelper {
             public void onError(Throwable throwable) {
                 super.onError(throwable);
                 responseCallback.onError(throwable);
-                if (countDownLatch != null){
+                if (countDownLatch != null) {
                     countDownLatch.countDown();
                 }
             }
         };
     }
 
-    public void fixRelations(IRelationshipProvider relationshipProvider) {
+    public void fixRelations(@NonNull IRelationshipProvider relationshipProvider) {
         // this is OK, since the delete only affects records with status UP_TO_DATE
         relationshipProvider.deleteAllExisting(dataBaseAdapter, accountId);
         relationshipProvider.insertAllNecessary(dataBaseAdapter, accountId);
     }
 
-    private <T extends IRemoteEntity> T applyUpdatesFromRemote(AbstractSyncDataProvider<T> provider, T localEntity, T remoteEntity, Long accountId) {
+    private <T extends IRemoteEntity> T applyUpdatesFromRemote(@NonNull AbstractSyncDataProvider<T> provider, @NonNull T localEntity, @NonNull T remoteEntity, @NonNull Long accountId) {
         if (!accountId.equals(localEntity.getAccountId())) {
             throw new IllegalArgumentException("IDs of Accounts are not matching! WTF are you doin?!");
         }
@@ -160,7 +183,7 @@ public class SyncHelper {
         return remoteEntity;
     }
 
-    public SyncHelper setResponseCallback(IResponseCallback<Boolean> callback) {
+    public SyncHelper setResponseCallback(@NonNull IResponseCallback<Boolean> callback) {
         this.responseCallback = callback;
         this.account = responseCallback.getAccount();
         accountId = account.getId();
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AbstractSyncDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AbstractSyncDataProvider.java
index 166d6c519..11fb38a66 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AbstractSyncDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AbstractSyncDataProvider.java
@@ -1,9 +1,10 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import java.time.Instant;
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.List;
 
+import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.model.interfaces.IRemoteEntity;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
@@ -26,28 +27,37 @@ public abstract class AbstractSyncDataProvider<T extends IRemoteEntity> {
         }
     }
 
-    public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<T> entitiesFromServer){
+    public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<T> entitiesFromServer) {
         // do nothing as a default.
     }
 
     /**
      * Searches each entry of <code>listB</code> in list <code>listA</code> and returns the missing ones
+     *
      * @param listA List
      * @param listB List
      * @return all entries of <code>listB</code> missing in <code>listA</code>
      */
-    public static <T extends IRemoteEntity> List<T> findDelta(List<T> listA, List<T> listB){
+    public static <T extends IRemoteEntity> List<T> findDelta(List<T> listA, List<T> listB) {
         List<T> delta = new ArrayList<>();
         for (T b : listB) {
+            if (b == null) {
+                DeckLog.error("Entry in listB is null! skipping...");
+                continue;
+            }
             boolean found = false;
             for (T a : listA) {
-                if ((a.getLocalId()!= null && b.getLocalId()!= null ? (a.getLocalId().equals(b.getLocalId()))
+                if (a == null) {
+                    DeckLog.error("Entry in listA is null! skipping...");
+                    continue;
+                }
+                if ((a.getLocalId() != null && b.getLocalId() != null ? (a.getLocalId().equals(b.getLocalId()))
                         : a.getId().equals(b.getId())) && b.getAccountId() == a.getAccountId()) {
                     found = true;
                     break;
                 }
             }
-            if (!found){
+            if (!found) {
                 delta.add(b);
             }
         }
@@ -58,7 +68,14 @@ public abstract class AbstractSyncDataProvider<T extends IRemoteEntity> {
         children.add(child);
     }
 
-    public abstract void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<T>> responder, Date lastSync);
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<T>> responder, Instant lastSync) {
+        return;
+    }
+
+    public void getAllFromServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<List<T>> responder, Instant lastSync) {
+        // Overridden, because we also need the DB-Adapter at some points here (see ACL data provider)
+        getAllFromServer(serverAdapter, accountId, responder, lastSync);
+    }
 
     public abstract T getSingleFromDB(DataBaseAdapter dataBaseAdapter, long accountId, T entity);
 
@@ -72,7 +89,7 @@ public abstract class AbstractSyncDataProvider<T extends IRemoteEntity> {
 
     public abstract void deleteInDB(DataBaseAdapter dataBaseAdapter, long accountId, T t);
 
-    public void deletePhysicallyInDB(DataBaseAdapter dataBaseAdapter, long accountId, T t){
+    public void deletePhysicallyInDB(DataBaseAdapter dataBaseAdapter, long accountId, T t) {
         deleteInDB(dataBaseAdapter, accountId, t);
     }
 
@@ -106,7 +123,7 @@ public abstract class AbstractSyncDataProvider<T extends IRemoteEntity> {
         stillGoingDeeper = true;
     }
 
-    public abstract List<T> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync);
+    public abstract List<T> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync);
 
     public void goDeeperForUpSync(SyncHelper syncHelper, ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, IResponseCallback<Boolean> callback) {
         //do nothing
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AccessControlDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AccessControlDataProvider.java
index 3242ab7c1..6dde6b45c 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AccessControlDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AccessControlDataProvider.java
@@ -1,17 +1,24 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
+import java.util.concurrent.CountDownLatch;
 
+import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.model.AccessControl;
+import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.User;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
+import it.niedermann.nextcloud.deck.model.ocs.user.GroupMemberUIDs;
+import it.niedermann.nextcloud.deck.model.ocs.user.OcsUser;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.util.AsyncUtil;
 
 public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessControl> {
 
+    private static final Long TYPE_GROUP = 1L;
     private List<AccessControl> acl;
     private FullBoard board;
 
@@ -22,10 +29,66 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<AccessControl>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<List<AccessControl>> responder, Instant lastSync) {
+        AsyncUtil.awaitAsyncWork(acl.size(), latch -> {
+            for (AccessControl accessControl : acl) {
+                if (accessControl.getType() == TYPE_GROUP) {
+                    serverAdapter.searchGroupMembers(accessControl.getUser().getUid(), new IResponseCallback<GroupMemberUIDs>(responder.getAccount()) {
+                        @Override
+                        public void onResponse(GroupMemberUIDs response) {
+                            accessControl.setGroupMemberUIDs(response);
+                            if (response.getUids().size() > 0) {
+                                ensureGroupMembersInDB(getAccount(), dataBaseAdapter, serverAdapter, response);
+                            }
+                            latch.countDown();
+                        }
+
+                        @Override
+                        public void onError(Throwable throwable) {
+                            super.onError(throwable);
+                            latch.countDown();
+                        }
+                    });
+                } else latch.countDown();
+            }
+        });
+
         responder.onResponse(acl);
     }
 
+    private void ensureGroupMembersInDB(Account account, DataBaseAdapter dataBaseAdapter, ServerAdapter serverAdapter, GroupMemberUIDs response) {
+        CountDownLatch memberLatch = new CountDownLatch(response.getUids().size());
+        for (String uid : response.getUids()) {
+            User user = dataBaseAdapter.getUserByUidDirectly(account.getId(), uid);
+            if (user == null) {
+                // unknown user. fetch!
+                serverAdapter.getSingleUserData(uid, new IResponseCallback<OcsUser>(account) {
+                    @Override
+                    public void onResponse(OcsUser response) {
+                        DeckLog.log(response.toString());
+                        User user = new User();
+                        user.setUid(response.getId());
+                        user.setPrimaryKey(response.getId());
+                        user.setDisplayname(response.getDisplayName());
+                        dataBaseAdapter.createUser(account.getId(), user);
+                        memberLatch.countDown();
+                    }
+
+                    @Override
+                    public void onError(Throwable throwable) {
+                        super.onError(throwable);
+                        memberLatch.countDown();
+                    }
+                });
+            } else memberLatch.countDown();
+        }
+        try {
+            memberLatch.await();
+        } catch (InterruptedException e) {
+            DeckLog.logError(e);
+        }
+    }
+
     @Override
     public AccessControl getSingleFromDB(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl entity) {
         return dataBaseAdapter.getAccessControlByRemoteIdDirectly(accountId, entity.getEntity().getId());
@@ -34,7 +97,26 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     @Override
     public long createInDB(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl entity) {
         prepareUser(dataBaseAdapter, accountId, entity);
-        return dataBaseAdapter.createAccessControl(accountId, entity);
+        long newId = dataBaseAdapter.createAccessControl(accountId, entity);
+        entity.setLocalId(newId);
+        handleGroupMemberships(dataBaseAdapter, entity);
+        return newId;
+    }
+
+    private void handleGroupMemberships(DataBaseAdapter dataBaseAdapter, AccessControl entity) {
+        if (entity.getType() != TYPE_GROUP) {
+            return;
+        }
+        dataBaseAdapter.deleteGroupMembershipsOfGroup(entity.getUser().getLocalId());
+        if (entity.getGroupMemberUIDs() == null) {
+            return;
+        }
+        for (String groupMemberUID : entity.getGroupMemberUIDs().getUids()) {
+            User member = dataBaseAdapter.getUserByUidDirectly(entity.getAccountId(), groupMemberUID);
+            if (member != null) {
+                dataBaseAdapter.addUserToGroup(entity.getUserId(), member.getLocalId());
+            }
+        }
     }
 
     private void prepareUser(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl entity) {
@@ -42,6 +124,7 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
         if (user == null) {
             long userId = dataBaseAdapter.createUser(accountId, entity.getUser());
             entity.setUserId(userId);
+            entity.getUser().setLocalId(userId);
         } else {
             entity.setUserId(user.getLocalId());
             entity.getUser().setLocalId(user.getLocalId());
@@ -52,7 +135,9 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     @Override
     public void updateInDB(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl entity, boolean setStatus) {
         prepareUser(dataBaseAdapter, accountId, entity);
+        entity.setBoardId(board.getLocalId());
         dataBaseAdapter.updateAccessControl(entity, setStatus);
+        handleGroupMemberships(dataBaseAdapter, entity);
     }
 
     @Override
@@ -64,6 +149,9 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<AccessControl> responder, AccessControl entity) {
         AccessControl acl = new AccessControl(entity);
         acl.setBoardId(board.getBoard().getId());
+        if (acl.getUser() == null && acl.getUserId() != null) {
+            acl.setUser(dataBaseAdapter.getUserByLocalIdDirectly(acl.getUserId()));
+        }
         serverAdapter.createAccessControl(board.getBoard().getId(), acl, responder);
     }
 
@@ -79,6 +167,7 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
 
     @Override
     public void deletePhysicallyInDB(DataBaseAdapter dataBaseAdapter, long accountId, AccessControl accessControl) {
+        dataBaseAdapter.deleteGroupMembershipsOfGroup(accessControl.getUser().getLocalId());
         dataBaseAdapter.deleteAccessControl(accessControl, false);
     }
 
@@ -88,7 +177,7 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
     }
 
     @Override
-    public List<AccessControl> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<AccessControl> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return dataBaseAdapter.getLocallyChangedAccessControl(accountId, board.getLocalId());
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/ActivityDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/ActivityDataProvider.java
index a3785ca78..5a7abf732 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/ActivityDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/ActivityDataProvider.java
@@ -1,7 +1,9 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
-import java.util.ArrayList;
-import java.util.Date;
+import androidx.annotation.NonNull;
+
+import java.time.Instant;
+import java.util.Collections;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
@@ -12,15 +14,16 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter
 
 public class ActivityDataProvider extends AbstractSyncDataProvider<Activity> {
 
-    protected Card card;
+    @NonNull
+    private final Card card;
 
-    public ActivityDataProvider(AbstractSyncDataProvider<?> parent, Card card) {
+    public ActivityDataProvider(AbstractSyncDataProvider<?> parent, @NonNull Card card) {
         super(parent);
         this.card = card;
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Activity>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Activity>> responder, Instant lastSync) {
         serverAdapter.getActivitiesForCard(card.getId(), responder);
     }
 
@@ -65,7 +68,7 @@ public class ActivityDataProvider extends AbstractSyncDataProvider<Activity> {
     }
 
     @Override
-    public List<Activity> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
-        return new ArrayList<>();
+    public List<Activity> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
+        return Collections.emptyList();
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AttachmentDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AttachmentDataProvider.java
index 37e00dada..781f7b1f4 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AttachmentDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/AttachmentDataProvider.java
@@ -4,7 +4,7 @@ import android.net.Uri;
 
 import java.io.File;
 import java.io.IOException;
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
@@ -32,7 +32,7 @@ public class AttachmentDataProvider extends AbstractSyncDataProvider<Attachment>
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Attachment>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Attachment>> responder, Instant lastSync) {
         responder.onResponse(attachments);
     }
 
@@ -104,7 +104,7 @@ public class AttachmentDataProvider extends AbstractSyncDataProvider<Attachment>
     }
 
     @Override
-    public List<Attachment> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<Attachment> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return dataBaseAdapter.getLocallyChangedAttachmentsByLocalCardIdDirectly(accountId, card.getLocalId());
     }
 
@@ -120,7 +120,7 @@ public class AttachmentDataProvider extends AbstractSyncDataProvider<Attachment>
             dataBaseAdapter.deleteAttachment(accountId, attachment, false);
         }
         for (Attachment attachment : entitiesFromServer) {
-            if (attachment.getDeletedAt() != null && attachment.getDeletedAt().getTime() != 0) {
+            if (attachment.getDeletedAt() != null && attachment.getDeletedAt().toEpochMilli() != 0) {
                 Attachment toDelete = dataBaseAdapter.getAttachmentByRemoteIdDirectly(accountId, attachment.getId());
                 if (toDelete != null) {
                     dataBaseAdapter.deleteAttachment(accountId, toDelete, false);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java
index 98163029f..f5e071adb 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/BoardDataProvider.java
@@ -1,14 +1,16 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import android.annotation.SuppressLint;
+
+import com.nextcloud.android.sso.api.ParsedResponse;
+
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Date;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
-import java.util.concurrent.CountDownLatch;
 
-import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.model.AccessControl;
 import it.niedermann.nextcloud.deck.model.Board;
@@ -19,16 +21,33 @@ import it.niedermann.nextcloud.deck.model.full.FullStack;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.util.AsyncUtil;
 
 public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
 
-    public BoardDataProvider(){
+    public BoardDataProvider() {
         super(null);
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullBoard>> responder, Date lastSync) {
-        serverAdapter.getBoards(responder);
+    public void getAllFromServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<List<FullBoard>> responder, Instant lastSync) {
+        serverAdapter.getBoards(new IResponseCallback<ParsedResponse<List<FullBoard>>>(responder.getAccount()) {
+            @Override
+            public void onResponse(ParsedResponse<List<FullBoard>> response) {
+                String etag = response.getHeaders().get("ETag");
+                if (etag != null && !etag.equals(account.getBoardsEtag())) {
+                    account.setBoardsEtag(etag);
+                    dataBaseAdapter.updateAccount(account);
+                }
+                responder.onResponse(response.getResponse());
+            }
+
+            @SuppressLint("MissingSuperCall")
+            @Override
+            public void onError(Throwable throwable) {
+                responder.onError(throwable);
+            }
+        });
     }
 
     @Override
@@ -39,27 +58,65 @@ public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
     @Override
     public long createInDB(DataBaseAdapter dataBaseAdapter, long accountId, FullBoard entity) {
         handleOwner(dataBaseAdapter, accountId, entity);
-        return dataBaseAdapter.createBoardDirectly(accountId, entity.getBoard());
+        Long localId = dataBaseAdapter.createBoardDirectly(accountId, entity.getBoard());
+        entity.getBoard().setLocalId(localId);
+        handleUsers(dataBaseAdapter, accountId, entity);
+        return localId;
     }
 
     private void handleOwner(DataBaseAdapter dataBaseAdapter, long accountId, FullBoard entity) {
-        if (entity.getOwner()!=null) {
-            User remoteOwner = entity.getOwner();
-            User owner = dataBaseAdapter.getUserByUidDirectly(accountId, remoteOwner.getUid());
-            if (owner == null){
-                dataBaseAdapter.createUser(accountId, remoteOwner);
-            } else {
-                dataBaseAdapter.updateUser(accountId, remoteOwner, false);
-            }
-            owner = dataBaseAdapter.getUserByUidDirectly(accountId, remoteOwner.getUid());
+        if (entity.getOwner() != null) {
+            User owner = createOrUpdateUser(dataBaseAdapter, accountId, entity.getOwner());
             entity.getBoard().setOwnerId(owner.getLocalId());
         }
     }
 
+    private void handleUsers(DataBaseAdapter dataBaseAdapter, long accountId, FullBoard entity) {
+        dataBaseAdapter.deleteBoardMembershipsOfBoard(entity.getLocalId());
+        if (entity.getUsers() != null && !entity.getUsers().isEmpty()) {
+            for (User user : entity.getUsers()) {
+                if (user == null) {
+                    continue;
+                }
+                User existing = createOrUpdateUser(dataBaseAdapter, accountId, user);
+                dataBaseAdapter.addUserToBoard(existing.getLocalId(), entity.getLocalId());
+            }
+        }
+    }
+
+    private User createOrUpdateUser(DataBaseAdapter dataBaseAdapter, long accountId, User remoteUser) {
+        User owner = dataBaseAdapter.getUserByUidDirectly(accountId, remoteUser.getUid());
+        if (owner == null) {
+            dataBaseAdapter.createUser(accountId, remoteUser);
+        } else {
+            dataBaseAdapter.updateUser(accountId, remoteUser, false);
+        }
+        return dataBaseAdapter.getUserByUidDirectly(accountId, remoteUser.getUid());
+    }
+
     @Override
     public void updateInDB(DataBaseAdapter dataBaseAdapter, long accountId, FullBoard entity, boolean setStatus) {
+        handleDefaultLabels(dataBaseAdapter, entity);
         handleOwner(dataBaseAdapter, accountId, entity);
         dataBaseAdapter.updateBoard(entity.getBoard(), setStatus);
+        handleUsers(dataBaseAdapter, accountId, entity);
+    }
+
+    private void handleDefaultLabels(DataBaseAdapter dataBaseAdapter, FullBoard entity) {
+        // ## merge labels (created at board creation):
+        // the server creates four default labels. if a board is copied, they will also be copied. At sync, after creating the board, the labels are already there.
+        // this merges the created default ones with the ones i already have.
+        if (entity != null && entity.getLabels() != null) {
+            for (Label label : entity.getLabels()) {
+                // does this label exist and unknown to server yet?
+                Label existing = dataBaseAdapter.getLabelByBoardIdAndTitleDirectly(entity.getLocalId(), label.getTitle());
+                if (existing != null && existing.getId() == null) {
+                    // take our label and lets say it IS the same as on server (but use the local color, no matter what the server says)
+                    existing.setId(label.getId());
+                    dataBaseAdapter.updateLabel(existing, false);
+                }
+            }
+        }
     }
 
     @Override
@@ -71,19 +128,19 @@ public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
     @Override
     public void goDeeper(SyncHelper syncHelper, FullBoard existingEntity, FullBoard entityFromServer, IResponseCallback<Boolean> callback) {
         List<Label> labels = entityFromServer.getLabels();
-        if (labels != null && !labels.isEmpty()){
+        if (labels != null && !labels.isEmpty()) {
             syncHelper.doSyncFor(new LabelDataProvider(this, existingEntity.getBoard(), labels));
         }
 
         List<AccessControl> acl = entityFromServer.getParticipants();
-        if (acl != null && !acl.isEmpty()){
-            for (AccessControl ac : acl){
+        if (acl != null && !acl.isEmpty()) {
+            for (AccessControl ac : acl) {
                 ac.setBoardId(existingEntity.getLocalId());
             }
             syncHelper.doSyncFor(new AccessControlDataProvider(this, existingEntity, acl));
         }
 
-        if (entityFromServer.getStacks() != null && !entityFromServer.getStacks().isEmpty()){
+        if (entityFromServer.getStacks() != null && !entityFromServer.getStacks().isEmpty()) {
             syncHelper.doSyncFor(new StackDataProvider(this, existingEntity));
         }
     }
@@ -94,7 +151,7 @@ public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
     }
 
     @Override
-    public List<FullBoard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<FullBoard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return dataBaseAdapter.getLocallyChangedBoards(accountId);
     }
 
@@ -102,21 +159,17 @@ public class BoardDataProvider extends AbstractSyncDataProvider<FullBoard> {
     public void goDeeperForUpSync(SyncHelper syncHelper, ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, IResponseCallback<Boolean> callback) {
         Long accountId = callback.getAccount().getId();
         List<Label> locallyChangedLabels = dataBaseAdapter.getLocallyChangedLabels(accountId);
-        CountDownLatch countDownLatch = new CountDownLatch(locallyChangedLabels.size());
-        for (Label label : locallyChangedLabels) {
-            Board board = dataBaseAdapter.getBoardByLocalIdDirectly(label.getBoardId());
-            label.setBoardId(board.getId());
-            syncHelper.doUpSyncFor(new LabelDataProvider(this, board, Collections.singletonList(label)), countDownLatch);
-        }
-        try {
-            countDownLatch.await();
-        } catch (InterruptedException e) {
-            DeckLog.logError(e);
-        }
+        AsyncUtil.awaitAsyncWork(locallyChangedLabels.size(), (countDownLatch) -> {
+            for (Label label : locallyChangedLabels) {
+                Board board = dataBaseAdapter.getBoardByLocalIdDirectly(label.getBoardId());
+                label.setBoardId(board.getId());
+                syncHelper.doUpSyncFor(new LabelDataProvider(this, board, Collections.singletonList(label)), countDownLatch);
+            }
+        });
 
         List<Long> localBoardIDsWithChangedACL = dataBaseAdapter.getBoardIDsOfLocallyChangedAccessControl(accountId);
         for (Long boardId : localBoardIDsWithChangedACL) {
-            syncHelper.doUpSyncFor(new AccessControlDataProvider(this, dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, boardId) ,new ArrayList<>()));
+            syncHelper.doUpSyncFor(new AccessControlDataProvider(this, dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, boardId), new ArrayList<>()));
         }
 
         Set<Long> syncedBoards = new HashSet<>();
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java
index 03e02bd70..0ceac2cd8 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardDataProvider.java
@@ -1,12 +1,15 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import android.annotation.SuppressLint;
+
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Date;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.exceptions.DeckException;
 import it.niedermann.nextcloud.deck.exceptions.OfflineException;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
@@ -37,7 +40,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullCard>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullCard>> responder, Instant lastSync) {
 
         List<FullCard> result = new ArrayList<>();
         if (stack.getCards() == null || stack.getCards().isEmpty()) {
@@ -54,6 +57,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
                     }
                 }
 
+                @SuppressLint("MissingSuperCall")
                 @Override
                 public void onError(Throwable throwable) {
                     responder.onError(throwable);
@@ -70,7 +74,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     @Override
     public long createInDB(DataBaseAdapter dataBaseAdapter, long accountId, FullCard entity) {
         fixRelations(dataBaseAdapter, accountId, entity);
-        return dataBaseAdapter.createCard(accountId, entity.getCard());
+        return dataBaseAdapter.createCardDirectly(accountId, entity.getCard());
     }
 
     protected CardUpdate toCardUpdate(FullCard card) {
@@ -144,10 +148,17 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
         } else {
             DeckLog.verbose("Comments - Version is too low, DONT SYNC");
         }
+        syncHelper.doSyncFor(new OcsProjectDataProvider(this, existingEntity.getCard()));
     }
 
     @Override
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<FullCard> responder, FullCard entity) {
+        if (stack.getId() == null) {
+            responder.onError(new DeckException(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET, "Stack \"" +
+                    stack.getStack().getTitle() + "\" for Card \"" + entity.getCard().getTitle() +
+                    "\" is not synced yet. Perform a full sync (pull to refresh) as soon as you are online again."));
+            return;
+        }
         entity.getCard().setStackId(stack.getId());
         serverAdapter.createCard(board.getId(), stack.getId(), entity.getCard(), responder);
     }
@@ -170,7 +181,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     }
 
     @Override
-    public List<FullCard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<FullCard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         if (board == null || stack == null) {
             // no cards changed!
             // (see call from StackDataProvider: goDeeperForUpSync called with null for board.)
@@ -184,8 +195,13 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     public void goDeeperForUpSync(SyncHelper syncHelper, ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, IResponseCallback<Boolean> callback) {
         FullStack stack;
         Board board;
+        List<JoinCardWithLabel> changedLabels;
+        if (this.stack == null) {
+            changedLabels = dataBaseAdapter.getAllChangedLabelJoins();
+        } else {
+            changedLabels = dataBaseAdapter.getAllChangedLabelJoinsForStack(this.stack.getLocalId());
+        }
 
-        List<JoinCardWithLabel> changedLabels = dataBaseAdapter.getAllChangedJoins();
         Account account = callback.getAccount();
         for (JoinCardWithLabel changedLabelLocal : changedLabels) {
             Card card = dataBaseAdapter.getCardByLocalIdDirectly(account.getId(), changedLabelLocal.getCardId());
@@ -201,7 +217,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
                 board = this.board;
             }
 
-            JoinCardWithLabel changedLabel = dataBaseAdapter.getRemoteIdsForJoin(changedLabelLocal.getCardId(), changedLabelLocal.getLabelId());
+            JoinCardWithLabel changedLabel = dataBaseAdapter.getAllChangedLabelJoinsWithRemoteIDs(changedLabelLocal.getCardId(), changedLabelLocal.getLabelId());
             if (changedLabel.getStatusEnum() == DBStatus.LOCAL_DELETED) {
                 if (changedLabel.getLabelId() == null || changedLabel.getCardId() == null) {
                     dataBaseAdapter.deleteJoinedLabelForCardPhysicallyByRemoteIDs(account.getId(), changedLabel.getCardId(), changedLabel.getLabelId());
@@ -229,11 +245,22 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
 
             }
         }
-        List<JoinCardWithUser> deletedUsers = dataBaseAdapter.getAllDeletedUserJoinsWithRemoteIDs();
-        for (JoinCardWithUser deletedUser : deletedUsers) {
-            Card card = dataBaseAdapter.getCardByRemoteIdDirectly(account.getId(), deletedUser.getCardId());
+
+        List<JoinCardWithUser> changedUsers;
+        if (this.stack == null) {
+            changedUsers = dataBaseAdapter.getAllChangedUserJoinsWithRemoteIDs();
+        } else {
+            changedUsers = dataBaseAdapter.getAllChangedUserJoinsWithRemoteIDsForStack(this.stack.getLocalId());
+        }
+        for (JoinCardWithUser changedUser : changedUsers) {
+            // not already known to server?
+            if (changedUser.getCardId() == null) {
+                //skip for now
+                continue;
+            }
+            Card card = dataBaseAdapter.getCardByRemoteIdDirectly(account.getId(), changedUser.getCardId());
             if (this.stack == null) {
-                stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getLocalId());
+                stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getStackId());
             } else {
                 stack = this.stack;
             }
@@ -243,16 +270,16 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
             } else {
                 board = this.board;
             }
-            User user = dataBaseAdapter.getUserByLocalIdDirectly(deletedUser.getUserId());
-            if (deletedUser.getStatusEnum() == DBStatus.LOCAL_DELETED) {
-                serverAdapter.unassignUserFromCard(board.getId(), stack.getId(), deletedUser.getCardId(), user.getUid(), new IResponseCallback<Void>(account) {
+            User user = dataBaseAdapter.getUserByLocalIdDirectly(changedUser.getUserId());
+            if (changedUser.getStatusEnum() == DBStatus.LOCAL_DELETED) {
+                serverAdapter.unassignUserFromCard(board.getId(), stack.getId(), changedUser.getCardId(), user.getUid(), new IResponseCallback<Void>(account) {
                     @Override
                     public void onResponse(Void response) {
-                        dataBaseAdapter.deleteJoinedUserForCardPhysicallyByRemoteIDs(account.getId(), deletedUser.getCardId(), user.getUid());
+                        dataBaseAdapter.deleteJoinedUserForCardPhysicallyByRemoteIDs(account.getId(), changedUser.getCardId(), user.getUid());
                     }
                 });
-            } else if (deletedUser.getStatusEnum() == DBStatus.LOCAL_EDITED) {
-                serverAdapter.assignUserToCard(board.getId(), stack.getId(), deletedUser.getCardId(), user.getUid(), new IResponseCallback<Void>(account) {
+            } else if (changedUser.getStatusEnum() == DBStatus.LOCAL_EDITED) {
+                serverAdapter.assignUserToCard(board.getId(), stack.getId(), changedUser.getCardId(), user.getUid(), new IResponseCallback<Void>(account) {
                     @Override
                     public void onResponse(Void response) {
                         dataBaseAdapter.setStatusForJoinCardWithUser(card.getLocalId(), user.getLocalId(), DBStatus.UP_TO_DATE.getId());
@@ -261,7 +288,12 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
             }
         }
 
-        List<Attachment> attachments = dataBaseAdapter.getLocallyChangedAttachmentsDirectly(account.getId());
+        List<Attachment> attachments;
+        if (this.stack == null) {
+            attachments = dataBaseAdapter.getLocallyChangedAttachmentsDirectly(account.getId());
+        } else {
+            attachments = dataBaseAdapter.getLocallyChangedAttachmentsForStackDirectly(this.stack.getLocalId());
+        }
         for (Attachment attachment : attachments) {
             FullCard card = dataBaseAdapter.getFullCardByLocalIdDirectly(account.getId(), attachment.getCardId());
             stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getCard().getStackId());
@@ -269,7 +301,12 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
             syncHelper.doUpSyncFor(new AttachmentDataProvider(this, board, stack.getStack(), card, Collections.singletonList(attachment)));
         }
 
-        List<Card> cardsWithChangedComments = dataBaseAdapter.getCardsWithLocallyChangedCommentsDirectly(account.getId());
+        List<Card> cardsWithChangedComments;
+        if (this.stack == null) {
+            cardsWithChangedComments = dataBaseAdapter.getCardsWithLocallyChangedCommentsDirectly(account.getId());
+        } else {
+            cardsWithChangedComments = dataBaseAdapter.getCardsWithLocallyChangedCommentsForStackDirectly(this.stack.getLocalId());
+        }
         for (Card card : cardsWithChangedComments) {
             syncHelper.doUpSyncFor(new DeckCommentsDataProvider(this, card));
         }
@@ -279,7 +316,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
 
     @Override
     public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<FullCard> entitiesFromServer) {
-        List<FullCard> localCards = dataBaseAdapter.getFullCardsForStackDirectly(accountId, stack.getLocalId());
+        List<FullCard> localCards = dataBaseAdapter.getFullCardsForStackDirectly(accountId, stack.getLocalId(), null);
         List<FullCard> delta = findDelta(entitiesFromServer, localCards);
         for (FullCard cardToDelete : delta) {
             if (cardToDelete.getId() == null) {
@@ -294,6 +331,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
                         // do not delete, it's still there and was just moved!
                     }
 
+                    @SuppressLint("MissingSuperCall")
                     @Override
                     public void onError(Throwable throwable) {
                         if (!(throwable instanceof OfflineException)) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/DeckCommentsDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/DeckCommentsDataProvider.java
index 5b9be120f..06ef3030d 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/DeckCommentsDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/DeckCommentsDataProvider.java
@@ -1,8 +1,8 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Date;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
@@ -24,10 +24,13 @@ public class DeckCommentsDataProvider extends AbstractSyncDataProvider<OcsCommen
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<OcsComment>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<OcsComment>> responder, Instant lastSync) {
         serverAdapter.getCommentsForRemoteCardId(card.getId(), new IResponseCallback<OcsComment>(responder.getAccount()) {
             @Override
             public void onResponse(OcsComment response) {
+                if (response == null) {
+                    response = new OcsComment();
+                }
                 List<OcsComment> comments = response.split();
                 Collections.sort(comments, (o1, o2) -> o1.getSingle().getCreationDateTime().compareTo(o2.getSingle().getCreationDateTime()));
                 verifyCommentListIntegrity(comments);
@@ -131,7 +134,7 @@ public class DeckCommentsDataProvider extends AbstractSyncDataProvider<OcsCommen
     }
 
     @Override
-    public List<OcsComment> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<OcsComment> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return new OcsComment(dataBaseAdapter.getLocallyChangedCommentsByLocalCardIdDirectly(accountId, card.getLocalId())).split();
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/LabelDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/LabelDataProvider.java
index 403d71f87..caa7c68e6 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/LabelDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/LabelDataProvider.java
@@ -1,8 +1,9 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
 
+import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.exceptions.HandledServerErrors;
 import it.niedermann.nextcloud.deck.model.Board;
@@ -12,14 +13,14 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter
 
 public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
 
-    private List<Label> labels;
-    private Board board;
+    private final List<Label> labels;
+    private final Board board;
 
     public LabelDataProvider(AbstractSyncDataProvider<?> parent, Board board, List<Label> labels) {
         super(parent);
         this.board = board;
         this.labels = labels;
-        if (this.labels!= null && board != null){
+        if (this.labels != null && board != null) {
             for (Label label : labels) {
                 label.setBoardId(board.getLocalId());
             }
@@ -27,7 +28,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Label>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<Label>> responder, Instant lastSync) {
         responder.onResponse(labels);
     }
 
@@ -44,7 +45,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
             updateInDB(dataBaseAdapter, accountId, entity, false);
             return entity.getLocalId();
         } else {
-            return dataBaseAdapter.createLabel(accountId, entity);
+            return dataBaseAdapter.createLabelDirectly(accountId, entity);
         }
     }
 
@@ -53,7 +54,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
         dataBaseAdapter.updateLabel(entity, setStatus);
     }
 
-    private IResponseCallback<Label> getLabelUniqueHandler(DataBaseAdapter dataBaseAdapter, Label entitiy, IResponseCallback<Label> responder){
+    private IResponseCallback<Label> getLabelUniqueHandler(DataBaseAdapter dataBaseAdapter, Label entitiy, IResponseCallback<Label> responder) {
         return new IResponseCallback<Label>(responder.getAccount()) {
             @Override
             public void onResponse(Label response) {
@@ -62,10 +63,13 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
 
             @Override
             public void onError(Throwable throwable) {
-                if (HandledServerErrors.LABELS_TITLE_MUST_BE_UNIQUE == HandledServerErrors.fromThrowable(throwable)){
+                if (HandledServerErrors.LABELS_TITLE_MUST_BE_UNIQUE == HandledServerErrors.fromThrowable(throwable)) {
+                    DeckLog.log(throwable.getCause().getMessage() + ": " + entitiy.toString());
                     dataBaseAdapter.deleteLabelPhysically(entitiy);
+                    responder.onResponse(entitiy);
+                } else {
+                    responder.onError(throwable);
                 }
-                responder.onError(throwable);
             }
         };
     }
@@ -92,7 +96,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
     }
 
     @Override
-    public List<Label> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<Label> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return labels;
     }
 
@@ -105,7 +109,7 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
     public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<Label> entitiesFromServer) {
         List<Label> deletedLabels = findDelta(labels, dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, board.getLocalId()).getLabels());
         for (Label deletedLabel : deletedLabels) {
-            if (deletedLabel.getId()!=null){
+            if (deletedLabel.getId() != null) {
                 // preserve new, unsynced card.
                 dataBaseAdapter.deleteLabelPhysically(deletedLabel);
             }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/OcsProjectDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/OcsProjectDataProvider.java
new file mode 100644
index 000000000..b9bfb8b31
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/OcsProjectDataProvider.java
@@ -0,0 +1,100 @@
+package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
+
+import java.time.Instant;
+import java.util.Collections;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProject;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectList;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
+
+public class OcsProjectDataProvider extends AbstractSyncDataProvider<OcsProject> {
+    private Card card;
+
+    public OcsProjectDataProvider(AbstractSyncDataProvider<?> parent, Card card) {
+        super(parent);
+        this.card = card;
+    }
+
+    @Override
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<OcsProject>> responder, Instant lastSync) {
+        serverAdapter.getProjectsForCard(card.getId(), new IResponseCallback<OcsProjectList>(responder.getAccount()) {
+            @Override
+            public void onResponse(OcsProjectList response) {
+                responder.onResponse(response.getProjects());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                super.onError(throwable);
+                // dont break the sync!
+                DeckLog.logError(throwable);
+                responder.onResponse(Collections.emptyList());
+            }
+        });
+    }
+
+    @Override
+    public OcsProject getSingleFromDB(DataBaseAdapter dataBaseAdapter, long accountId, OcsProject entity) {
+        return dataBaseAdapter.getProjectByRemoteIdDirectly(accountId, entity.getId());
+    }
+
+    @Override
+    public long createInDB(DataBaseAdapter dataBaseAdapter, long accountId, OcsProject entity) {
+        Long newId = dataBaseAdapter.createProjectDirectly(accountId, entity);
+        entity.setLocalId(newId);
+        updateResources(dataBaseAdapter, accountId, entity);
+        return newId;
+    }
+
+    @Override
+    public void updateInDB(DataBaseAdapter dataBaseAdapter, long accountId, OcsProject entity, boolean setStatus) {
+        dataBaseAdapter.updateProjectDirectly(accountId, entity);
+        dataBaseAdapter.deleteProjectResourcesForProjectIdDirectly(entity.getLocalId());
+        updateResources(dataBaseAdapter, accountId, entity);
+    }
+
+    @Override
+    public void deleteInDB(DataBaseAdapter dataBaseAdapter, long accountId, OcsProject ocsProject) {
+        if (ocsProject != null && ocsProject.getLocalId() != null) {
+            dataBaseAdapter.deleteProjectDirectly(ocsProject);
+        }
+    }
+
+    private void updateResources(DataBaseAdapter dataBaseAdapter, Long accountId, OcsProject entity) {
+        if (entity.getResources() != null) {
+            for (OcsProjectResource resource : entity.getResources()) {
+                resource.setProjectId(entity.getLocalId());
+                resource.setLocalId(dataBaseAdapter.createProjectResourceDirectly(accountId, resource));
+                if ("deck-card".equals(resource.getType())) {
+                    dataBaseAdapter.assignCardToProjectIfMissng(accountId, entity.getLocalId(), resource.getId());
+                }
+            }
+        }
+    }
+
+    @Override
+    public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<OcsProject> responder, OcsProject entity) {
+        // Do Nothing
+    }
+
+    @Override
+    public void updateOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<OcsProject> callback, OcsProject entity) {
+        // Do Nothing
+    }
+
+    @Override
+    public void deleteOnServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<Void> callback, OcsProject entity, DataBaseAdapter dataBaseAdapter) {
+        // Do Nothing
+    }
+
+    @Override
+    public List<OcsProject> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
+        return Collections.emptyList();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java
index a3c123afd..93761d616 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/StackDataProvider.java
@@ -1,12 +1,13 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import java.time.Instant;
 import java.util.Collections;
-import java.util.Date;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.ConcurrentSkipListSet;
 
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.exceptions.DeckException;
 import it.niedermann.nextcloud.deck.model.Board;
 import it.niedermann.nextcloud.deck.model.Card;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
@@ -19,13 +20,15 @@ import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
 public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
     private FullBoard board;
 
+    private Set<Long> syncedStacks = new ConcurrentSkipListSet<>();
+
     public StackDataProvider(AbstractSyncDataProvider<?> parent, FullBoard board) {
         super(parent);
         this.board = board;
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullStack>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<FullStack>> responder, Instant lastSync) {
         serverAdapter.getStacks(board.getId(), responder);
     }
 
@@ -54,12 +57,12 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
 
     @Override
     public void goDeeper(SyncHelper syncHelper, FullStack existingEntity, FullStack entityFromServer, IResponseCallback<Boolean> callback) {
-       boolean serverHasCards = entityFromServer.getCards() != null && !entityFromServer.getCards().isEmpty();
-       boolean weHaveCards = existingEntity.getCards() != null && !existingEntity.getCards().isEmpty();
-        if (serverHasCards || weHaveCards){
+        boolean serverHasCards = entityFromServer.getCards() != null && !entityFromServer.getCards().isEmpty();
+        boolean weHaveCards = existingEntity.getCards() != null && !existingEntity.getCards().isEmpty();
+        if (serverHasCards || weHaveCards) {
             existingEntity.setCards(entityFromServer.getCards());
             List<Card> cards = existingEntity.getCards();
-            if (cards != null ){
+            if (cards != null) {
                 for (Card card : cards) {
                     card.setStackId(existingEntity.getLocalId());
                 }
@@ -72,6 +75,9 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
 
     @Override
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<FullStack> responder, FullStack entity) {
+        if (board.getId() == null) {
+            throw new DeckException(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET, "Board for this stack is not synced yet. Perform a full sync (pull to referesh) as soon as you are online again.");
+        }
         entity.getStack().setBoardId(board.getId());
         serverAdapter.createStack(board.getBoard(), entity.getStack(), responder);
     }
@@ -89,8 +95,8 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
     }
 
     @Override
-    public List<FullStack> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
-        if (board == null){
+    public List<FullStack> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
+        if (board == null) {
             // no stacks changed!
             // (see call from BoardDataProvider: goDeeperForUpSync called with null for board.)
             // so we can just skip this one and proceed with cards.
@@ -103,16 +109,19 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
     @Override
     public void goDeeperForUpSync(SyncHelper syncHelper, ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, IResponseCallback<Boolean> callback) {
         List<FullCard> changedCards = dataBaseAdapter.getLocallyChangedCardsDirectly(callback.getAccount().getId());
-        Set<Long> syncedStacks = new HashSet<>();
-        if (changedCards != null && changedCards.size() > 0){
+        if (changedCards != null && !changedCards.isEmpty()) {
             for (FullCard changedCard : changedCards) {
                 long stackId = changedCard.getCard().getStackId();
-                boolean added = syncedStacks.add(stackId);
-                if (added) {
+                boolean alreadySynced = syncedStacks.contains(stackId);
+                if (!alreadySynced) {
                     FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(stackId);
-                    Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
-                    changedCard.getCard().setStackId(stack.getId());
-                    syncHelper.doUpSyncFor(new CardDataProvider(this, board, stack));
+                    // already synced and known to server?
+                    if (stack.getStack().getId() != null) {
+                        syncedStacks.add(stackId);
+                        Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
+                        changedCard.getCard().setStackId(stack.getId());
+                        syncHelper.doUpSyncFor(new CardDataProvider(this, board, stack));
+                    }
                 }
             }
         } else {
@@ -132,7 +141,7 @@ public class StackDataProvider extends AbstractSyncDataProvider<FullStack> {
         List<FullStack> localStacks = dataBaseAdapter.getFullStacksForBoardDirectly(accountId, board.getLocalId());
         List<FullStack> delta = findDelta(entitiesFromServer, localStacks);
         for (FullStack stackToDelete : delta) {
-            if (stackToDelete.getId() == null){
+            if (stackToDelete.getId() == null) {
                 // not pushed up yet so:
                 continue;
             }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/UserDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/UserDataProvider.java
index 60c906bda..279ce9e55 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/UserDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/UserDataProvider.java
@@ -1,6 +1,6 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
@@ -27,7 +27,7 @@ public class UserDataProvider extends AbstractSyncDataProvider<User> {
     }
 
     @Override
-    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<User>> responder, Date lastSync) {
+    public void getAllFromServer(ServerAdapter serverAdapter, long accountId, IResponseCallback<List<User>> responder, Instant lastSync) {
         responder.onResponse(users);
     }
 
@@ -67,7 +67,7 @@ public class UserDataProvider extends AbstractSyncDataProvider<User> {
     }
 
     @Override
-    public List<User> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Date lastSync) {
+    public List<User> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
         return null;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWitAclDownSyncDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithAclDownSyncDataProvider.java
index 326d257ab..8516f0fc0 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWitAclDownSyncDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithAclDownSyncDataProvider.java
@@ -11,7 +11,7 @@ import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.AccessControlDataProvider;
 import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.BoardDataProvider;
 
-public class BoardWitAclDownSyncDataProvider extends BoardDataProvider {
+public class BoardWithAclDownSyncDataProvider extends BoardDataProvider {
 
     @Override
     public void goDeeper(SyncHelper syncHelper, FullBoard existingEntity, FullBoard entityFromServer, IResponseCallback<Boolean> callback) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithStacksAndLabelsUpSyncDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithStacksAndLabelsUpSyncDataProvider.java
new file mode 100644
index 000000000..5f2c79ad3
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/partial/BoardWithStacksAndLabelsUpSyncDataProvider.java
@@ -0,0 +1,37 @@
+package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.partial;
+
+import java.time.Instant;
+import java.util.Collections;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.model.full.FullBoard;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
+import it.niedermann.nextcloud.deck.persistence.sync.helpers.providers.BoardDataProvider;
+
+public class BoardWithStacksAndLabelsUpSyncDataProvider extends BoardDataProvider {
+
+    private FullBoard board;
+
+    public BoardWithStacksAndLabelsUpSyncDataProvider(FullBoard boardToSync) {
+        board = boardToSync;
+    }
+
+    @Override
+    public List<FullBoard> getAllChangedFromDB(DataBaseAdapter dataBaseAdapter, long accountId, Instant lastSync) {
+        return Collections.singletonList(board);
+    }
+
+    @Override
+    public void goDeeper(SyncHelper syncHelper, FullBoard existingEntity, FullBoard entityFromServer, IResponseCallback<Boolean> callback) {
+        // do nothing!
+
+    }
+
+    @Override
+    public void handleDeletes(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, List<FullBoard> entitiesFromServer) {
+        // do nothing!
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/util/AsyncUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/util/AsyncUtil.java
new file mode 100644
index 000000000..faabda163
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/util/AsyncUtil.java
@@ -0,0 +1,21 @@
+package it.niedermann.nextcloud.deck.persistence.sync.helpers.util;
+
+import java.util.concurrent.CountDownLatch;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+
+public class AsyncUtil {
+    public interface LatchCallback {
+        void doWork(CountDownLatch latch);
+    }
+
+    public static void awaitAsyncWork(int count, LatchCallback worker){
+        CountDownLatch countDownLatch = new CountDownLatch(count);
+        worker.doWork(countDownLatch);
+        try {
+            countDownLatch.await();
+        } catch (InterruptedException e) {
+            DeckLog.logError(e);
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/ImportAccountActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/ImportAccountActivity.java
index 854b99a6a..3ded31bb7 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/ImportAccountActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/ImportAccountActivity.java
@@ -23,6 +23,7 @@ import com.nextcloud.android.sso.exceptions.AndroidGetAccountsPermissionNotGrant
 import com.nextcloud.android.sso.exceptions.NextcloudFilesAppNotInstalledException;
 import com.nextcloud.android.sso.helper.SingleAccountHelper;
 import com.nextcloud.android.sso.model.SingleSignOnAccount;
+import com.nextcloud.android.sso.ui.UiExceptionManager;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
@@ -36,7 +37,6 @@ import it.niedermann.nextcloud.deck.persistence.sync.SyncWorker;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
-import it.niedermann.nextcloud.deck.util.ExceptionUtil;
 
 import static com.nextcloud.android.sso.AccountImporter.REQUEST_AUTH_TOKEN_SSO;
 
@@ -79,7 +79,11 @@ public class ImportAccountActivity extends AppCompatActivity {
             try {
                 AccountImporter.pickNewAccount(this);
             } catch (NextcloudFilesAppNotInstalledException e) {
-                ExceptionUtil.handleNextcloudFilesAppNotInstalledException(this, e);
+                UiExceptionManager.showDialogForException(this, e);
+                DeckLog.warn("=============================================================");
+                DeckLog.warn("Nextcloud app is not installed. Cannot choose account");
+                DeckLog.logError(e);
+                binding.addButton.setEnabled(true);
             } catch (AndroidGetAccountsPermissionNotGranted e) {
                 binding.addButton.setEnabled(true);
                 AccountImporter.requestAndroidAccountPermissionsAndPickAccount(this);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainActivity.java
index b5713909b..d7e726a7d 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainActivity.java
@@ -1,5 +1,6 @@
 package it.niedermann.nextcloud.deck.ui;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
@@ -53,6 +54,7 @@ import java.util.Objects;
 import it.niedermann.android.crosstabdnd.CrossTabDragAndDrop;
 import it.niedermann.android.tablayouthelper.TabLayoutHelper;
 import it.niedermann.android.tablayouthelper.TabTitleGenerator;
+import it.niedermann.nextcloud.deck.DeckApplication;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
@@ -65,6 +67,7 @@ import it.niedermann.nextcloud.deck.model.Stack;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
 import it.niedermann.nextcloud.deck.model.full.FullStack;
+import it.niedermann.nextcloud.deck.model.internal.FilterInformation;
 import it.niedermann.nextcloud.deck.model.ocs.Capabilities;
 import it.niedermann.nextcloud.deck.model.ocs.Version;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
@@ -86,6 +89,7 @@ import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
 import it.niedermann.nextcloud.deck.ui.filter.FilterDialogFragment;
 import it.niedermann.nextcloud.deck.ui.filter.FilterViewModel;
+import it.niedermann.nextcloud.deck.ui.pickstack.PickStackViewModel;
 import it.niedermann.nextcloud.deck.ui.settings.SettingsActivity;
 import it.niedermann.nextcloud.deck.ui.stack.DeleteStackDialogFragment;
 import it.niedermann.nextcloud.deck.ui.stack.DeleteStackListener;
@@ -112,8 +116,8 @@ import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.applyBrandTo
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.clearBrandColors;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.saveBrandColors;
-import static it.niedermann.nextcloud.deck.util.ColorUtil.contrastRatioIsSufficient;
-import static it.niedermann.nextcloud.deck.util.ColorUtil.contrastRatioIsSufficientBigAreas;
+import static it.niedermann.nextcloud.deck.util.DeckColorUtil.contrastRatioIsSufficient;
+import static it.niedermann.nextcloud.deck.util.DeckColorUtil.contrastRatioIsSufficientBigAreas;
 import static it.niedermann.nextcloud.deck.util.DrawerMenuUtil.MENU_ID_ABOUT;
 import static it.niedermann.nextcloud.deck.util.DrawerMenuUtil.MENU_ID_ADD_BOARD;
 import static it.niedermann.nextcloud.deck.util.DrawerMenuUtil.MENU_ID_ARCHIVED_BOARDS;
@@ -126,6 +130,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
     protected MainViewModel mainViewModel;
     private FilterViewModel filterViewModel;
+    private PickStackViewModel pickStackViewModel;
 
     protected static final int ACTIVITY_ABOUT = 1;
     protected static final int ACTIVITY_SETTINGS = 2;
@@ -133,7 +138,6 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
     @NonNull
     protected List<Account> accountsList = new ArrayList<>();
-    protected SyncManager syncManager;
     protected SharedPreferences sharedPreferences;
     private StackAdapter stackAdapter;
     long lastBoardId;
@@ -143,7 +147,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
     private Observer<List<Board>> boardsLiveDataObserver;
     private Menu listMenu;
 
-    private LiveData<List<FullStack>> stacksLiveData;
+    private LiveData<List<Stack>> stacksLiveData;
 
     private LiveData<Boolean> hasArchivedBoardsLiveData;
     private Observer<Boolean> hasArchivedBoardsLiveDataObserver;
@@ -178,6 +182,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
         mainViewModel = new ViewModelProvider(this).get(MainViewModel.class);
         filterViewModel = new ViewModelProvider(this).get(FilterViewModel.class);
+        pickStackViewModel = new ViewModelProvider(this).get(PickStackViewModel.class);
 
         addList = getString(R.string.add_list);
         addBoard = getString(R.string.add_board);
@@ -191,12 +196,11 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
         toggle.syncState();
 
         binding.navigationView.setNavigationItemSelectedListener(this);
-        syncManager = new SyncManager(this);
         sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
 
-        switchMap(syncManager.hasAccounts(), hasAccounts -> {
+        switchMap(mainViewModel.hasAccounts(), hasAccounts -> {
             if (hasAccounts) {
-                return syncManager.readAccounts();
+                return mainViewModel.readAccounts();
             } else {
                 startActivityForResult(new Intent(this, ImportAccountActivity.class), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
                 return null;
@@ -220,7 +224,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                             registerAutoSyncOnNetworkAvailable();
                         } else {
-                            syncManager.synchronize(new IResponseCallback<Boolean>(mainViewModel.getCurrentAccount()) {
+                            mainViewModel.synchronize(new IResponseCallback<Boolean>(mainViewModel.getCurrentAccount()) {
                                 @Override
                                 public void onResponse(Boolean response) {
                                 }
@@ -240,7 +244,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
             mainViewModel.getCurrentAccountLiveData().observe(this, (currentAccount) -> {
                 SingleAccountHelper.setCurrentAccount(getApplicationContext(), mainViewModel.getCurrentAccount().getName());
-                syncManager = new SyncManager(this);
+                mainViewModel.recreateSyncManager();
 
                 saveCurrentAccountId(this, mainViewModel.getCurrentAccount().getId());
                 if (mainViewModel.getCurrentAccount().isMaintenanceEnabled()) {
@@ -253,7 +257,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                     boardsLiveData.removeObserver(boardsLiveDataObserver);
                 }
 
-                boardsLiveData = syncManager.getBoards(currentAccount.getId(), false);
+                boardsLiveData = mainViewModel.getBoards(currentAccount.getId(), false);
                 boardsLiveDataObserver = (boards) -> {
                     if (boards == null) {
                         throw new IllegalStateException("List<Board> boards must not be null.");
@@ -273,15 +277,19 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                         if (!currentBoardIdWasInList) {
                             setCurrentBoard(boardsList.get(0));
                         }
+
+                        binding.filter.setOnClickListener((v) -> FilterDialogFragment.newInstance().show(getSupportFragmentManager(), EditStackDialogFragment.class.getCanonicalName()));
                     } else {
                         clearBrandColors(this);
                         clearCurrentBoard();
+
+                        binding.filter.setOnClickListener(null);
                     }
 
                     if (hasArchivedBoardsLiveData != null && hasArchivedBoardsLiveDataObserver != null) {
                         hasArchivedBoardsLiveData.removeObserver(hasArchivedBoardsLiveDataObserver);
                     }
-                    hasArchivedBoardsLiveData = syncManager.hasArchivedBoards(currentAccount.getId());
+                    hasArchivedBoardsLiveData = mainViewModel.hasArchivedBoards(currentAccount.getId());
                     hasArchivedBoardsLiveDataObserver = (hasArchivedBoards) -> {
                         mainViewModel.setCurrentAccountHasArchivedBoards(Boolean.TRUE.equals(hasArchivedBoards));
                         inflateBoardMenu();
@@ -320,7 +328,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
             CrossTabDragAndDrop<StackFragment, CardAdapter, FullCard> dragAndDrop = new CrossTabDragAndDrop<>(getResources(), ViewCompat.getLayoutDirection(binding.getRoot()) == ViewCompat.LAYOUT_DIRECTION_LTR);
             dragAndDrop.register(binding.viewPager, binding.stackTitles, getSupportFragmentManager());
             dragAndDrop.addItemMovedByDragListener((movedCard, stackId, position) -> {
-                syncManager.reorder(mainViewModel.getCurrentAccount().getId(), movedCard, stackId, position);
+                mainViewModel.reorder(mainViewModel.getCurrentAccount().getId(), movedCard, stackId, position);
                 DeckLog.info("Card \"" + movedCard.getCard().getTitle() + "\" was moved to Stack " + stackId + " on position " + position);
             });
 
@@ -374,8 +382,6 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
             });
             filterViewModel.getFilterInformation().observe(this, (info) ->
                     binding.filterIndicator.setVisibility(filterViewModel.getFilterInformation().getValue() == null ? View.GONE : View.VISIBLE));
-
-            binding.filter.setOnClickListener((v) -> FilterDialogFragment.newInstance().show(getSupportFragmentManager(), EditStackDialogFragment.class.getCanonicalName()));
             binding.archivedCards.setOnClickListener((v) -> startActivity(ArchivedCardsActvitiy.createIntent(this, mainViewModel.getCurrentAccount(), mainViewModel.getCurrentBoardLocalId(), mainViewModel.currentBoardHasEditPermission())));
 
 
@@ -395,7 +401,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                     }
                 } else DeckLog.warn("ConnectivityManager is null");
                 refreshCapabilities(mainViewModel.getCurrentAccount());
-                syncManager.synchronize(new IResponseCallback<Boolean>(mainViewModel.getCurrentAccount()) {
+                mainViewModel.synchronize(new IResponseCallback<Boolean>(mainViewModel.getCurrentAccount()) {
                     @Override
                     public void onResponse(Boolean response) {
                         runOnUiThread(() -> binding.swipeRefreshLayout.setRefreshing(false));
@@ -422,7 +428,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
         applyBrandToPrimaryTabLayout(mainColor, binding.stackTitles);
         applyBrandToFAB(mainColor, binding.fab);
         // TODO We assume, that the background of the spinner is always white
-        binding.swipeRefreshLayout.setColorSchemeColors(contrastRatioIsSufficient(Color.WHITE, mainColor) ? mainColor : colorAccent);
+        binding.swipeRefreshLayout.setColorSchemeColors(contrastRatioIsSufficient(Color.WHITE, mainColor) ? mainColor : DeckApplication.isDarkTheme(this) ? Color.DKGRAY : colorAccent);
         headerBinding.headerView.setBackgroundColor(mainColor);
         @ColorInt final int headerTextColor = contrastRatioIsSufficientBigAreas(mainColor, Color.WHITE) ? Color.WHITE : Color.BLACK;
         DrawableCompat.setTint(headerBinding.logo.getDrawable(), headerTextColor);
@@ -440,62 +446,49 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
     @Override
     public void onCreateStack(String stackName) {
-        // TODO this outer call is only necessary to get the highest order. Move logic to SyncManager.
-        observeOnce(syncManager.getStacksForBoard(mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId()), MainActivity.this, fullStacks -> {
-            final Stack s = new Stack(stackName, mainViewModel.getCurrentBoardLocalId());
-            int heighestOrder = 0;
-            for (FullStack fullStack : fullStacks) {
-                int currentStackOrder = fullStack.stack.getOrder();
-                if (currentStackOrder >= heighestOrder) {
-                    heighestOrder = currentStackOrder + 1;
-                }
+        DeckLog.info("Create Stack in account " + mainViewModel.getCurrentAccount().getName() + " on board " + mainViewModel.getCurrentBoardLocalId());
+        WrappedLiveData<FullStack> createLiveData = mainViewModel.createStack(mainViewModel.getCurrentAccount().getId(), stackName, mainViewModel.getCurrentBoardLocalId());
+        observeOnce(createLiveData, this, (fullStack) -> {
+            if (createLiveData.hasError()) {
+                final Throwable error = createLiveData.getError();
+                assert error != null;
+                BrandedSnackbar.make(binding.coordinatorLayout, Objects.requireNonNull(error.getLocalizedMessage()), Snackbar.LENGTH_LONG)
+                        .setAction(R.string.simple_more, v -> ExceptionDialogFragment.newInstance(error, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()))
+                        .show();
+            } else {
+                binding.viewPager.setCurrentItem(stackAdapter.getItemCount());
             }
-            s.setOrder(heighestOrder);
-            DeckLog.info("Create Stack in account " + mainViewModel.getCurrentAccount().getName() + " on board " + mainViewModel.getCurrentBoardLocalId());
-            WrappedLiveData<FullStack> createLiveData = syncManager.createStack(mainViewModel.getCurrentAccount().getId(), s);
-            observeOnce(createLiveData, this, (fullStack) -> {
-                if (createLiveData.hasError()) {
-                    final Throwable error = createLiveData.getError();
-                    assert error != null;
-                    BrandedSnackbar.make(binding.coordinatorLayout, Objects.requireNonNull(error.getLocalizedMessage()), Snackbar.LENGTH_LONG)
-                            .setAction(R.string.simple_more, v -> ExceptionDialogFragment.newInstance(error, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()))
-                            .show();
-                } else {
-                    binding.viewPager.setCurrentItem(stackAdapter.getItemCount());
-                }
-            });
         });
     }
 
     @Override
     public void onUpdateStack(long localStackId, String stackName) {
-        observeOnce(syncManager.getStack(mainViewModel.getCurrentAccount().getId(), localStackId), MainActivity.this, fullStack -> {
-            fullStack.getStack().setTitle(stackName);
-            final WrappedLiveData<FullStack> archiveLiveData = syncManager.updateStack(fullStack);
-            observeOnce(archiveLiveData, this, (v) -> {
-                if (archiveLiveData.hasError()) {
-                    ExceptionDialogFragment.newInstance(archiveLiveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
-                }
-            });
+        final WrappedLiveData<FullStack> liveData = mainViewModel.updateStackTitle(localStackId, stackName);
+        observeOnce(liveData, this, (v) -> {
+            if (liveData.hasError()) {
+                ExceptionDialogFragment.newInstance(liveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
         });
     }
 
     @Override
-    public void onCreateBoard(String title, String color) {
+    public void onCreateBoard(String title, @ColorInt int color) {
         if (boardsLiveData == null || boardsLiveDataObserver == null) {
             throw new IllegalStateException("Cannot create board when noone observe boards yet. boardsLiveData or observer is null.");
         }
         boardsLiveData.removeObserver(boardsLiveDataObserver);
-        final Board boardToCreate = new Board(title, color.startsWith("#") ? color.substring(1) : color);
+        final Board boardToCreate = new Board(title, color);
         boardToCreate.setPermissionEdit(true);
         boardToCreate.setPermissionManage(true);
-        observeOnce(syncManager.createBoard(mainViewModel.getCurrentAccount().getId(), boardToCreate), this, createdBoard -> {
-            if (createdBoard == null) {
-                BrandedSnackbar.make(binding.coordinatorLayout, "Open Deck in web interface first!", Snackbar.LENGTH_LONG)
-                        // TODO implement action!
-                        // .setAction(R.string.simple_open, v -> ExceptionDialogFragment.newInstance(throwable).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()))
+
+        final WrappedLiveData<FullBoard> createLiveData = mainViewModel.createBoard(mainViewModel.getCurrentAccount().getId(), boardToCreate);
+        observeOnce(createLiveData, this, (createdBoard) -> {
+            if (createLiveData.hasError()) {
+                BrandedSnackbar.make(binding.coordinatorLayout, R.string.synchronization_failed, Snackbar.LENGTH_LONG)
+                        .setAction(R.string.simple_more, v -> ExceptionDialogFragment.newInstance(createLiveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()))
                         .show();
-            } else {
+            }
+            if (createdBoard != null && !createLiveData.hasError()) {
                 boardsList.add(createdBoard.getBoard());
                 setCurrentBoard(createdBoard.getBoard());
 
@@ -508,11 +501,16 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
     @Override
     public void onUpdateBoard(FullBoard fullBoard) {
-        syncManager.updateBoard(fullBoard);
+        final WrappedLiveData<FullBoard> updateLiveData = mainViewModel.updateBoard(fullBoard);
+        observeOnce(updateLiveData, this, (next) -> {
+            if (updateLiveData.hasError()) {
+                ExceptionDialogFragment.newInstance(updateLiveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
     }
 
     private void refreshCapabilities(final Account account) {
-        syncManager.refreshCapabilities(new IResponseCallback<Capabilities>(account) {
+        mainViewModel.refreshCapabilities(new IResponseCallback<Capabilities>(account) {
             @Override
             public void onResponse(Capabilities response) {
                 if (response.isMaintenanceEnabled()) {
@@ -548,7 +546,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
         if (stacksLiveData != null) {
             stacksLiveData.removeObservers(this);
         }
-        saveBrandColors(this, Color.parseColor('#' + board.getColor()));
+        saveBrandColors(this, board.getColor());
         mainViewModel.setCurrentBoard(board);
         filterViewModel.clearFilterInformation();
 
@@ -569,12 +567,12 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
         binding.emptyContentViewBoards.setVisibility(View.GONE);
         binding.swipeRefreshLayout.setVisibility(View.VISIBLE);
 
-        stacksLiveData = syncManager.getStacksForBoard(mainViewModel.getCurrentAccount().getId(), board.getLocalId());
-        stacksLiveData.observe(this, (List<FullStack> fullStacks) -> {
-            if (fullStacks == null) {
+        stacksLiveData = mainViewModel.getStacksForBoard(mainViewModel.getCurrentAccount().getId(), board.getLocalId());
+        stacksLiveData.observe(this, (List<Stack> stacks) -> {
+            if (stacks == null) {
                 throw new IllegalStateException("Given List<FullStack> must not be null");
             }
-            currentBoardStacksCount = fullStacks.size();
+            currentBoardStacksCount = stacks.size();
 
             if (currentBoardStacksCount == 0) {
                 binding.emptyContentViewStacks.setVisibility(View.VISIBLE);
@@ -586,19 +584,19 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
             listMenu.findItem(R.id.archive_cards).setVisible(currentBoardHasStacks);
 
             int stackPositionInAdapter = 0;
-            stackAdapter.setStacks(fullStacks);
+            stackAdapter.setStacks(stacks);
 
             long currentStackId = readCurrentStackId(this, mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId());
             for (int i = 0; i < currentBoardStacksCount; i++) {
-                if (fullStacks.get(i).getLocalId() == currentStackId || currentStackId == NO_STACK_ID) {
+                if (stacks.get(i).getLocalId() == currentStackId || currentStackId == NO_STACK_ID) {
                     stackPositionInAdapter = i;
                     break;
                 }
             }
             final int stackPositionInAdapterClone = stackPositionInAdapter;
             final TabTitleGenerator tabTitleGenerator = position -> {
-                if (fullStacks.size() > position) {
-                    return fullStacks.get(position).getStack().getTitle();
+                if (stacks.size() > position) {
+                    return stacks.get(position).getTitle();
                 } else {
                     DeckLog.logError(new IllegalStateException("Could not generate tab title for position " + position + " because list size is only " + currentBoardStacksCount));
                     return "ERROR";
@@ -671,71 +669,67 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
-        switch (item.getItemId()) {
-            case R.id.archive_cards: {
-                final FullStack fullStack = stackAdapter.getItem(binding.viewPager.getCurrentItem());
-                final long stackLocalId = fullStack.getLocalId();
-                observeOnce(syncManager.countCardsInStack(mainViewModel.getCurrentAccount().getId(), stackLocalId), MainActivity.this, (numberOfCards) -> {
-                    new BrandedAlertDialogBuilder(this)
-                            .setTitle(R.string.archive_cards)
-                            .setMessage(getString(R.string.do_you_want_to_archive_all_cards_of_the_list, fullStack.getStack().getTitle()))
-                            .setPositiveButton(R.string.simple_archive, (dialog, whichButton) -> {
-                                final WrappedLiveData<Void> archiveStackLiveData = syncManager.archiveCardsInStack(mainViewModel.getCurrentAccount().getId(), stackLocalId);
-                                observeOnce(archiveStackLiveData, this, (result) -> {
-                                    if (archiveStackLiveData.hasError()) {
-                                        ExceptionDialogFragment.newInstance(archiveStackLiveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
-                                    }
-                                });
-                            })
-                            .setNeutralButton(android.R.string.cancel, null)
-                            .create()
-                            .show();
-                });
-                return true;
-            }
-            case R.id.add_list: {
-                EditStackDialogFragment.newInstance(NO_STACK_ID).show(getSupportFragmentManager(), addList);
-                return true;
-            }
-            case R.id.rename_list: {
-                final long stackId = stackAdapter.getItem(binding.viewPager.getCurrentItem()).getLocalId();
-                observeOnce(syncManager.getStack(mainViewModel.getCurrentAccount().getId(), stackId), MainActivity.this, fullStack ->
-                        EditStackDialogFragment.newInstance(fullStack.getLocalId(), fullStack.getStack().getTitle())
-                                .show(getSupportFragmentManager(), EditStackDialogFragment.class.getCanonicalName()));
-                return true;
-            }
-            case R.id.move_list_left: {
-                final long stackId = stackAdapter.getItem(binding.viewPager.getCurrentItem()).getLocalId();
-                // TODO error handling
-                final int stackLeftPosition = binding.viewPager.getCurrentItem() - 1;
-                final long stackLeftId = stackAdapter.getItem(stackLeftPosition).getLocalId();
-                syncManager.swapStackOrder(mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId(), new Pair<>(stackId, stackLeftId));
-                stackMoved = true;
-                return true;
-            }
-            case R.id.move_list_right: {
-                final long stackId = stackAdapter.getItem(binding.viewPager.getCurrentItem()).getLocalId();
-                // TODO error handling
-                final int stackRightPosition = binding.viewPager.getCurrentItem() + 1;
-                final long stackRightId = stackAdapter.getItem(stackRightPosition).getLocalId();
-                syncManager.swapStackOrder(mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId(), new Pair<>(stackId, stackRightId));
-                stackMoved = true;
-                return true;
-            }
-            case R.id.delete_list: {
-                final long stackId = stackAdapter.getItem(binding.viewPager.getCurrentItem()).getLocalId();
-                observeOnce(syncManager.countCardsInStack(mainViewModel.getCurrentAccount().getId(), stackId), MainActivity.this, (numberOfCards) -> {
-                    if (numberOfCards != null && numberOfCards > 0) {
-                        DeleteStackDialogFragment.newInstance(stackId, numberOfCards).show(getSupportFragmentManager(), DeleteStackDialogFragment.class.getCanonicalName());
-                    } else {
-                        onStackDeleted(stackId);
-                    }
-                });
-                return true;
-            }
-            default:
-                return super.onOptionsItemSelected(item);
+        int itemId = item.getItemId();
+        if (itemId == R.id.archive_cards) {
+            final Stack stack = stackAdapter.getItem(binding.viewPager.getCurrentItem());
+            final long stackLocalId = stack.getLocalId();
+            observeOnce(mainViewModel.countCardsInStack(mainViewModel.getCurrentAccount().getId(), stackLocalId), MainActivity.this, (numberOfCards) -> {
+                new BrandedAlertDialogBuilder(this)
+                        .setTitle(R.string.archive_cards)
+                        .setMessage(getString(FilterInformation.hasActiveFilter(filterViewModel.getFilterInformation().getValue())
+                                ? R.string.do_you_want_to_archive_all_cards_of_the_filtered_list
+                                : R.string.do_you_want_to_archive_all_cards_of_the_list, stack.getTitle()))
+                        .setPositiveButton(R.string.simple_archive, (dialog, whichButton) -> {
+                            final FilterInformation filterInformation = filterViewModel.getFilterInformation().getValue();
+                            final WrappedLiveData<Void> archiveStackLiveData = mainViewModel.archiveCardsInStack(mainViewModel.getCurrentAccount().getId(), stackLocalId, filterInformation == null ? new FilterInformation() : filterInformation);
+                            observeOnce(archiveStackLiveData, this, (result) -> {
+                                if (archiveStackLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(archiveStackLiveData.getError())) {
+                                    ExceptionDialogFragment.newInstance(archiveStackLiveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                                }
+                            });
+                        })
+                        .setNeutralButton(android.R.string.cancel, null)
+                        .create()
+                        .show();
+            });
+            return true;
+        } else if (itemId == R.id.add_list) {
+            EditStackDialogFragment.newInstance(NO_STACK_ID).show(getSupportFragmentManager(), addList);
+            return true;
+        } else if (itemId == R.id.rename_list) {
+            final long stackId = stackAdapter.getItem(binding.viewPager.getCurrentItem()).getLocalId();
+            observeOnce(mainViewModel.getStack(mainViewModel.getCurrentAccount().getId(), stackId), MainActivity.this, fullStack ->
+                    EditStackDialogFragment.newInstance(fullStack.getLocalId(), fullStack.getStack().getTitle())
+                            .show(getSupportFragmentManager(), EditStackDialogFragment.class.getCanonicalName()));
+            return true;
+        } else if (itemId == R.id.move_list_left) {
+            final long stackId = stackAdapter.getItem(binding.viewPager.getCurrentItem()).getLocalId();
+            // TODO error handling
+            final int stackLeftPosition = binding.viewPager.getCurrentItem() - 1;
+            final long stackLeftId = stackAdapter.getItem(stackLeftPosition).getLocalId();
+            mainViewModel.swapStackOrder(mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId(), new Pair<>(stackId, stackLeftId));
+            stackMoved = true;
+            return true;
+        } else if (itemId == R.id.move_list_right) {
+            final long stackId = stackAdapter.getItem(binding.viewPager.getCurrentItem()).getLocalId();
+            // TODO error handling
+            final int stackRightPosition = binding.viewPager.getCurrentItem() + 1;
+            final long stackRightId = stackAdapter.getItem(stackRightPosition).getLocalId();
+            mainViewModel.swapStackOrder(mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId(), new Pair<>(stackId, stackRightId));
+            stackMoved = true;
+            return true;
+        } else if (itemId == R.id.delete_list) {
+            final long stackId = stackAdapter.getItem(binding.viewPager.getCurrentItem()).getLocalId();
+            observeOnce(mainViewModel.countCardsInStack(mainViewModel.getCurrentAccount().getId(), stackId), MainActivity.this, (numberOfCards) -> {
+                if (numberOfCards != null && numberOfCards > 0) {
+                    DeleteStackDialogFragment.newInstance(stackId, numberOfCards).show(getSupportFragmentManager(), DeleteStackDialogFragment.class.getCanonicalName());
+                } else {
+                    onStackDeleted(stackId);
+                }
+            });
+            return true;
         }
+        return super.onOptionsItemSelected(item);
     }
 
     protected void showFabIfEditPermissionGranted() {
@@ -780,7 +774,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
             default:
                 try {
                     AccountImporter.onActivityResult(requestCode, resultCode, data, this, (account) -> {
-                        final WrappedLiveData<Account> accountLiveData = this.syncManager.createAccount(new Account(account.name, account.userId, account.url));
+                        final WrappedLiveData<Account> accountLiveData = mainViewModel.createAccount(new Account(account.name, account.userId, account.url));
                         accountLiveData.observe(this, (createdAccount) -> {
                             if (!accountLiveData.hasError()) {
                                 if (createdAccount == null) {
@@ -789,12 +783,13 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
                                 final SyncManager importSyncManager = new SyncManager(this, account.name);
                                 importSyncManager.refreshCapabilities(new IResponseCallback<Capabilities>(createdAccount) {
+                                    @SuppressLint("StringFormatInvalid")
                                     @Override
                                     public void onResponse(Capabilities response) {
                                         if (!response.isMaintenanceEnabled()) {
                                             if (response.getDeckVersion().isSupported(getApplicationContext())) {
                                                 runOnUiThread(() -> {
-                                                    syncManager = importSyncManager;
+                                                    mainViewModel.setSyncManager(importSyncManager);
                                                     mainViewModel.setCurrentAccount(account);
 
                                                     final Snackbar importSnackbar = BrandedSnackbar.make(binding.coordinatorLayout, R.string.account_is_getting_imported, Snackbar.LENGTH_INDEFINITE);
@@ -827,7 +822,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                                                             startActivity(openURL);
                                                             finish();
                                                         }).show());
-                                                syncManager.deleteAccount(createdAccount.getId());
+                                                mainViewModel.deleteAccount(createdAccount.getId());
                                             }
                                         } else {
                                             DeckLog.warn("Cannot import account because server version is currently in maintenance mode.");
@@ -836,14 +831,14 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                                                     .setMessage(getString(R.string.maintenance_mode_explanation, createdAccount.getUrl()))
                                                     .setPositiveButton(R.string.simple_close, null)
                                                     .show());
-                                            syncManager.deleteAccount(createdAccount.getId());
+                                            mainViewModel.deleteAccount(createdAccount.getId());
                                         }
                                     }
 
                                     @Override
                                     public void onError(Throwable throwable) {
                                         super.onError(throwable);
-                                        syncManager.deleteAccount(createdAccount.getId());
+                                        mainViewModel.deleteAccount(createdAccount.getId());
                                         if (throwable instanceof OfflineException) {
                                             DeckLog.warn("Cannot import account because device is currently offline.");
                                             runOnUiThread(() -> new BrandedAlertDialogBuilder(MainActivity.this)
@@ -893,7 +888,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                     @Override
                     public void onAvailable(@NonNull Network network) {
                         DeckLog.log("Got Network connection");
-                        syncManager.synchronize(new IResponseCallback<Boolean>(mainViewModel.getCurrentAccount()) {
+                        mainViewModel.synchronize(new IResponseCallback<Boolean>(mainViewModel.getCurrentAccount()) {
                             @Override
                             public void onResponse(Boolean response) {
                                 DeckLog.log("Auto-Sync after connection available successful");
@@ -924,9 +919,9 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
     @Override
     public void onStackDeleted(Long stackLocalId) {
         long stackId = stackAdapter.getItem(binding.viewPager.getCurrentItem()).getLocalId();
-        final WrappedLiveData<Void> deleteStackLiveData = syncManager.deleteStack(mainViewModel.getCurrentAccount().getId(), stackId, mainViewModel.getCurrentBoardLocalId());
+        final WrappedLiveData<Void> deleteStackLiveData = mainViewModel.deleteStack(mainViewModel.getCurrentAccount().getId(), stackId, mainViewModel.getCurrentBoardLocalId());
         observeOnce(deleteStackLiveData, this, (v) -> {
-            if (deleteStackLiveData.hasError()) {
+            if (deleteStackLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteStackLiveData.getError())) {
                 ExceptionDialogFragment.newInstance(deleteStackLiveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
             }
         });
@@ -946,7 +941,14 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                 EditBoardDialogFragment.newInstance().show(getSupportFragmentManager(), addBoard);
             }
         }
-        syncManager.deleteBoard(board);
+
+        final WrappedLiveData<Void> deleteLiveData = mainViewModel.deleteBoard(board);
+        observeOnce(deleteLiveData, this, (next) -> {
+            if (deleteLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteLiveData.getError())) {
+                ExceptionDialogFragment.newInstance(deleteLiveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
+
         binding.drawerLayout.closeDrawer(GravityCompat.START);
     }
 
@@ -966,6 +968,39 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
     @Override
     public void onArchive(@NonNull Board board) {
-        syncManager.archiveBoard(board);
+        final WrappedLiveData<FullBoard> liveData = mainViewModel.archiveBoard(board);
+        observeOnce(liveData, this, (fullBoard) -> {
+            if (liveData.hasError()) {
+                ExceptionDialogFragment.newInstance(liveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
+    }
+
+    @Override
+    public void onClone(Board board) {
+        final String[] animals = {getString(R.string.clone_cards)};
+        final boolean[] checkedItems = {false};
+        new BrandedAlertDialogBuilder(this)
+                .setTitle(R.string.clone_board)
+                .setMultiChoiceItems(animals, checkedItems, (dialog, which, isChecked) -> checkedItems[0] = isChecked)
+                .setPositiveButton(R.string.simple_clone, (dialog, which) -> {
+                    binding.drawerLayout.closeDrawer(GravityCompat.START);
+                    final Snackbar snackbar = BrandedSnackbar.make(binding.coordinatorLayout, getString(R.string.cloning_board, board.getTitle()), Snackbar.LENGTH_INDEFINITE);
+                    snackbar.show();
+                    final WrappedLiveData<FullBoard> liveData = mainViewModel.cloneBoard(board.getAccountId(), board.getLocalId(), board.getAccountId(), board.getColor(), checkedItems[0]);
+                    observeOnce(liveData, this, (fullBoard -> {
+                        snackbar.dismiss();
+                        if (liveData.hasError()) {
+                            ExceptionDialogFragment.newInstance(liveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                        } else {
+                            setCurrentBoard(fullBoard.getBoard());
+                            BrandedSnackbar.make(binding.coordinatorLayout, getString(R.string.successfully_cloned_board, fullBoard.getBoard().getTitle()), Snackbar.LENGTH_LONG)
+                                    .setAction(R.string.edit, v -> EditBoardDialogFragment.newInstance(fullBoard.getLocalId()).show(getSupportFragmentManager(), EditBoardDialogFragment.class.getSimpleName()))
+                                    .show();
+                        }
+                    }));
+                })
+                .setNeutralButton(android.R.string.cancel, null)
+                .show();
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainViewModel.java
index e5bd4f482..ac244b88e 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainViewModel.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/MainViewModel.java
@@ -2,19 +2,42 @@ package it.niedermann.nextcloud.deck.ui;
 
 import android.app.Application;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.core.util.Pair;
 import androidx.lifecycle.AndroidViewModel;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
 
+import java.io.File;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.model.AccessControl;
 import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Attachment;
 import it.niedermann.nextcloud.deck.model.Board;
+import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.model.Label;
+import it.niedermann.nextcloud.deck.model.Stack;
+import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.model.full.FullBoard;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.model.full.FullStack;
+import it.niedermann.nextcloud.deck.model.internal.FilterInformation;
+import it.niedermann.nextcloud.deck.model.ocs.Capabilities;
+import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 
 @SuppressWarnings("WeakerAccess")
 public class MainViewModel extends AndroidViewModel {
 
-    private MutableLiveData<Account> currentAccount = new MutableLiveData<>();
+    private SyncManager syncManager;
+
+    private final MutableLiveData<Account> currentAccount = new MutableLiveData<>();
+    @Nullable
     private Board currentBoard;
     private boolean currentAccountHasArchivedBoards = false;
 
@@ -22,6 +45,7 @@ public class MainViewModel extends AndroidViewModel {
 
     public MainViewModel(@NonNull Application application) {
         super(application);
+        this.syncManager = new SyncManager(application);
     }
 
     public Account getCurrentAccount() {
@@ -37,16 +61,21 @@ public class MainViewModel extends AndroidViewModel {
         this.currentAccountIsSupportedVersion = currentAccount.getServerDeckVersionAsObject().isSupported(getApplication().getApplicationContext());
     }
 
-    public void setCurrentBoard(Board currentBoard) {
+    public void setCurrentBoard(@NonNull Board currentBoard) {
         this.currentBoard = currentBoard;
     }
 
     public Long getCurrentBoardLocalId() {
+        if (currentBoard == null) {
+            throw new IllegalStateException("getCurrentBoardLocalId() called before setCurrentBoard()");
+        }
         return this.currentBoard.getLocalId();
     }
 
-    @Nullable
     public Long getCurrentBoardRemoteId() {
+        if (currentBoard == null) {
+            throw new IllegalStateException("getCurrentBoardRemoteId() called before setCurrentBoard()");
+        }
         return this.currentBoard.getId();
     }
 
@@ -65,4 +94,192 @@ public class MainViewModel extends AndroidViewModel {
     public boolean isCurrentAccountIsSupportedVersion() {
         return currentAccountIsSupportedVersion;
     }
+
+    public void recreateSyncManager() {
+        this.syncManager = new SyncManager(getApplication());
+    }
+
+    public void setSyncManager(@NonNull SyncManager syncManager) {
+        this.syncManager = syncManager;
+    }
+
+    public void synchronize(@NonNull IResponseCallback<Boolean> responseCallback) {
+        syncManager.synchronize(responseCallback);
+    }
+
+    public void refreshCapabilities(@NonNull IResponseCallback<Capabilities> callback) {
+        syncManager.refreshCapabilities(callback);
+    }
+
+    public LiveData<Boolean> hasAccounts() {
+        return syncManager.hasAccounts();
+    }
+
+    public WrappedLiveData<Account> createAccount(@NonNull Account accout) {
+        return syncManager.createAccount(accout);
+    }
+
+    public void deleteAccount(long id) {
+        syncManager.deleteAccount(id);
+    }
+
+    public LiveData<List<Account>> readAccounts() {
+        return syncManager.readAccounts();
+    }
+
+    public WrappedLiveData<FullBoard> createBoard(long accountId, @NonNull Board board) {
+        return syncManager.createBoard(accountId, board);
+    }
+
+    public WrappedLiveData<FullBoard> updateBoard(@NonNull FullBoard board) {
+        return syncManager.updateBoard(board);
+    }
+
+    public LiveData<List<Board>> getBoards(long accountId, boolean archived) {
+        return syncManager.getBoards(accountId, archived);
+    }
+
+    public LiveData<FullBoard> getFullBoardById(Long accountId, Long localId) {
+        return syncManager.getFullBoardById(accountId, localId);
+    }
+
+    public WrappedLiveData<FullBoard> archiveBoard(@NonNull Board board) {
+        return syncManager.archiveBoard(board);
+    }
+
+    public WrappedLiveData<FullBoard> dearchiveBoard(@NonNull Board board) {
+        return syncManager.dearchiveBoard(board);
+    }
+
+    public WrappedLiveData<FullBoard> cloneBoard(long originAccountId, long originBoardLocalId, long targetAccountId, @ColorInt int targetBoardColor, boolean cloneCards) {
+        return syncManager.cloneBoard(originAccountId, originBoardLocalId, targetAccountId, targetBoardColor, cloneCards);
+    }
+
+    public WrappedLiveData<Void> deleteBoard(@NonNull Board board) {
+        return syncManager.deleteBoard(board);
+    }
+
+    public LiveData<Boolean> hasArchivedBoards(long accountId) {
+        return syncManager.hasArchivedBoards(accountId);
+    }
+
+    public WrappedLiveData<AccessControl> createAccessControl(long accountId, AccessControl entity) {
+        return syncManager.createAccessControl(accountId, entity);
+    }
+
+    public WrappedLiveData<AccessControl> updateAccessControl(@NonNull AccessControl entity) {
+        return syncManager.updateAccessControl(entity);
+    }
+
+    public LiveData<List<AccessControl>> getAccessControlByLocalBoardId(long accountId, Long id) {
+        return syncManager.getAccessControlByLocalBoardId(accountId, id);
+    }
+
+    public WrappedLiveData<Void> deleteAccessControl(@NonNull AccessControl entity) {
+        return syncManager.deleteAccessControl(entity);
+    }
+
+    public WrappedLiveData<Label> createLabel(long accountId, Label label, long localBoardId) {
+        return syncManager.createLabel(accountId, label, localBoardId);
+    }
+
+    public LiveData<Integer> countCardsWithLabel(long localLabelId) {
+        return syncManager.countCardsWithLabel(localLabelId);
+    }
+
+    public WrappedLiveData<Label> updateLabel(@NonNull Label label) {
+        return syncManager.updateLabel(label);
+    }
+
+    public WrappedLiveData<Void> deleteLabel(@NonNull Label label) {
+        return syncManager.deleteLabel(label);
+    }
+
+    public LiveData<List<Stack>> getStacksForBoard(long accountId, long localBoardId) {
+        return syncManager.getStacksForBoard(accountId, localBoardId);
+    }
+
+    public WrappedLiveData<FullStack> createStack(long accountId, @NonNull String title, long boardLocalId) {
+        return syncManager.createStack(accountId, title, boardLocalId);
+    }
+
+    public LiveData<FullStack> getStack(long accountId, long localStackId) {
+        return syncManager.getStack(accountId, localStackId);
+    }
+
+    public void swapStackOrder(long accountId, long boardLocalId, @NonNull Pair<Long, Long> stackLocalIds) {
+        syncManager.swapStackOrder(accountId, boardLocalId, stackLocalIds);
+    }
+
+    public WrappedLiveData<FullStack> updateStackTitle(long localStackId, @NonNull String newTitle) {
+        return syncManager.updateStackTitle(localStackId, newTitle);
+    }
+
+    public WrappedLiveData<Void> deleteStack(long accountId, long stackLocalId, long boardLocalId) {
+        return syncManager.deleteStack(accountId, stackLocalId, boardLocalId);
+    }
+
+    public void reorder(long accountId, @NonNull FullCard movedCard, long newStackId, int newIndex) {
+        syncManager.reorder(accountId, movedCard, newStackId, newIndex);
+    }
+
+    public LiveData<Integer> countCardsInStack(long accountId, long localStackId) {
+        return syncManager.countCardsInStack(accountId, localStackId);
+    }
+
+    public WrappedLiveData<Void> archiveCardsInStack(long accountId, long stackLocalId, @NonNull FilterInformation filterInformation) {
+        return syncManager.archiveCardsInStack(accountId, stackLocalId, filterInformation);
+    }
+
+    public WrappedLiveData<FullCard> updateCard(@NonNull FullCard fullCard) {
+        return syncManager.updateCard(fullCard);
+    }
+
+    public void addCommentToCard(long accountId, long cardId, @NonNull DeckComment comment) {
+        syncManager.addCommentToCard(accountId, cardId, comment);
+    }
+
+    public WrappedLiveData<Attachment> addAttachmentToCard(long accountId, long localCardId, @NonNull String mimeType, @NonNull File file) {
+        return syncManager.addAttachmentToCard(accountId, localCardId, mimeType, file);
+    }
+
+    public void addOrUpdateSingleCardWidget(int widgetId, long accountId, long boardId, long localCardId) {
+        syncManager.addOrUpdateSingleCardWidget(widgetId, accountId, boardId, localCardId);
+    }
+
+    public LiveData<List<FullCard>> getFullCardsForStack(long accountId, long localStackId, @Nullable FilterInformation filter) {
+        return syncManager.getFullCardsForStack(accountId, localStackId, filter);
+    }
+
+    public WrappedLiveData<Void> moveCard(long originAccountId, long originCardLocalId, long targetAccountId, long targetBoardLocalId, long targetStackLocalId) {
+        return syncManager.moveCard(originAccountId, originCardLocalId, targetAccountId, targetBoardLocalId, targetStackLocalId);
+    }
+
+    public LiveData<List<FullCard>> getArchivedFullCardsForBoard(long accountId, long localBoardId) {
+        return syncManager.getArchivedFullCardsForBoard(accountId, localBoardId);
+    }
+
+    public void assignUserToCard(@NonNull User user, @NonNull Card card) {
+        syncManager.assignUserToCard(user, card);
+    }
+
+    public void unassignUserFromCard(@NonNull User user, @NonNull Card card) {
+        syncManager.unassignUserFromCard(user, card);
+    }
+
+    public User getUserByUidDirectly(long accountId, String uid) {
+        return syncManager.getUserByUidDirectly(accountId, uid);
+    }
+
+    public WrappedLiveData<FullCard> archiveCard(@NonNull FullCard card) {
+        return syncManager.archiveCard(card);
+    }
+
+    public WrappedLiveData<FullCard> dearchiveCard(@NonNull FullCard card) {
+        return syncManager.dearchiveCard(card);
+    }
+
+    public WrappedLiveData<Void> deleteCard(@NonNull Card card) {
+        return syncManager.deleteCard(card);
+    }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/PickStackActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/PickStackActivity.java
new file mode 100644
index 000000000..2339a8783
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/PickStackActivity.java
@@ -0,0 +1,115 @@
+package it.niedermann.nextcloud.deck.ui;
+
+import android.content.Intent;
+import android.content.res.ColorStateList;
+import android.graphics.Color;
+import android.os.Bundle;
+
+import androidx.annotation.ColorInt;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.core.content.ContextCompat;
+import androidx.core.graphics.drawable.DrawableCompat;
+import androidx.lifecycle.ViewModelProvider;
+
+import java.util.List;
+
+import it.niedermann.android.util.ColorUtil;
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ActivityPickStackBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Board;
+import it.niedermann.nextcloud.deck.model.Stack;
+import it.niedermann.nextcloud.deck.ui.branding.Branded;
+import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
+import it.niedermann.nextcloud.deck.ui.pickstack.PickStackFragment;
+import it.niedermann.nextcloud.deck.ui.pickstack.PickStackListener;
+import it.niedermann.nextcloud.deck.ui.pickstack.PickStackViewModel;
+
+import static androidx.lifecycle.Transformations.switchMap;
+import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
+import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
+import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
+import static it.niedermann.nextcloud.deck.util.DeckColorUtil.contrastRatioIsSufficientBigAreas;
+
+public abstract class PickStackActivity extends AppCompatActivity implements Branded, PickStackListener {
+
+    protected ActivityPickStackBinding binding;
+    protected PickStackViewModel viewModel;
+
+    private boolean brandingEnabled;
+
+    private Account selectedAccount;
+    private Board selectedBoard;
+    private Stack selectedStack;
+
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        Thread.setDefaultUncaughtExceptionHandler(new ExceptionHandler(this));
+
+        brandingEnabled = isBrandingEnabled(this);
+
+        binding = ActivityPickStackBinding.inflate(getLayoutInflater());
+        viewModel = new ViewModelProvider(this).get(PickStackViewModel.class);
+
+        setContentView(binding.getRoot());
+        setSupportActionBar(binding.toolbar);
+
+        switchMap(viewModel.hasAccounts(), hasAccounts -> {
+            if (hasAccounts) {
+                return viewModel.readAccounts();
+            } else {
+                startActivityForResult(new Intent(this, ImportAccountActivity.class), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
+                return null;
+            }
+        }).observe(this, (List<Account> accounts) -> {
+            if (accounts == null || accounts.size() == 0) {
+                throw new IllegalStateException("hasAccounts() returns true, but readAccounts() returns null or has no entry");
+            }
+            getSupportFragmentManager()
+                    .beginTransaction()
+                    .add(R.id.fragment_container, PickStackFragment.newInstance(showBoardsWithoutEditPermission()))
+                    .commit();
+        });
+        binding.cancel.setOnClickListener((v) -> finish());
+        binding.submit.setOnClickListener((v) -> onSubmit(selectedAccount, selectedBoard.getLocalId(), selectedStack.getLocalId()));
+    }
+
+    @Override
+    public void onStackPicked(@NonNull Account account, @Nullable Board board, @Nullable Stack stack) {
+        this.selectedAccount = account;
+        this.selectedBoard = board;
+        this.selectedStack = stack;
+        if (board == null) {
+            binding.submit.setEnabled(false);
+        } else {
+            applyBrand(board.getColor());
+            binding.submit.setEnabled(stack != null);
+        }
+    }
+
+    @Override
+    public void applyBrand(int mainColor) {
+        try {
+            if (brandingEnabled) {
+                @ColorInt final int finalMainColor = contrastRatioIsSufficientBigAreas(mainColor, ContextCompat.getColor(this, R.color.primary))
+                        ? mainColor
+                        : isDarkTheme(this) ? Color.WHITE : Color.BLACK;
+                DrawableCompat.setTintList(binding.submit.getBackground(), ColorStateList.valueOf(finalMainColor));
+                binding.submit.setTextColor(ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(finalMainColor));
+                binding.cancel.setTextColor(getSecondaryForegroundColorDependingOnTheme(this, mainColor));
+            }
+        } catch (Throwable t) {
+            DeckLog.logError(t);
+        }
+    }
+
+    abstract protected void onSubmit(Account account, long boardId, long stackId);
+
+    abstract protected boolean showBoardsWithoutEditPermission();
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/PushNotificationActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/PushNotificationActivity.java
index b0b0d68ae..cdc20ed50 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/PushNotificationActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/PushNotificationActivity.java
@@ -5,26 +5,28 @@ import android.net.Uri;
 import android.text.TextUtils;
 import android.view.View;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.UiThread;
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.lifecycle.ViewModelProvider;
 
-import com.nextcloud.android.sso.helper.SingleAccountHelper;
-
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.databinding.ActivityPushNotificationBinding;
 import it.niedermann.nextcloud.deck.model.Account;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 import it.niedermann.nextcloud.deck.ui.card.EditActivity;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
+import it.niedermann.nextcloud.deck.util.ProjectUtil;
 
-import static android.graphics.Color.parseColor;
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 
 public class PushNotificationActivity extends AppCompatActivity {
 
     private ActivityPushNotificationBinding binding;
+    private PushNotificationViewModel viewModel;
 
     // Provided by Files app NotificationJob
     private static final String KEY_SUBJECT = "subject";
@@ -44,6 +46,8 @@ public class PushNotificationActivity extends AppCompatActivity {
         }
 
         binding = ActivityPushNotificationBinding.inflate(getLayoutInflater());
+        viewModel = new ViewModelProvider(this).get(PushNotificationViewModel.class);
+
         setContentView(binding.getRoot());
         setSupportActionBar(binding.toolbar);
 
@@ -56,62 +60,105 @@ public class PushNotificationActivity extends AppCompatActivity {
         }
 
         final String link = getIntent().getStringExtra(KEY_LINK);
+        long[] ids = ProjectUtil.extractBoardIdAndCardIdFromUrl(link);
 
         binding.cancel.setOnClickListener((v) -> finish());
 
-        final SyncManager accountReadingSyncManager = new SyncManager(this);
         final String cardRemoteIdString = getIntent().getStringExtra(KEY_CARD_REMOTE_ID);
         final String accountString = getIntent().getStringExtra(KEY_ACCOUNT);
 
         DeckLog.verbose("cardRemoteIdString = " + cardRemoteIdString);
-        if (cardRemoteIdString != null) {
-            try {
-                final int cardRemoteId = Integer.parseInt(cardRemoteIdString);
-                observeOnce(accountReadingSyncManager.readAccount(accountString), this, (account -> {
-                    if (account != null) {
-                        SingleAccountHelper.setCurrentAccount(this, account.getName());
-                        final SyncManager syncManager = new SyncManager(this);
-                        DeckLog.verbose("account: " + account);
-                        observeOnce(syncManager.getLocalBoardIdByCardRemoteIdAndAccount(cardRemoteId, account), PushNotificationActivity.this, (boardLocalId -> {
-                            DeckLog.verbose("BoardLocalId " + boardLocalId);
-                            if (boardLocalId != null) {
-                                observeOnce(syncManager.synchronizeCardByRemoteId(cardRemoteId, account), PushNotificationActivity.this, (fullCard -> {
-                                    DeckLog.verbose("FullCard: " + fullCard);
-                                    if (fullCard != null) {
-                                        runOnUiThread(() -> {
-                                            binding.submit.setOnClickListener((v) -> launchEditActivity(account, boardLocalId, fullCard.getLocalId()));
-                                            binding.submit.setText(R.string.simple_open);
-                                            applyBrandToSubmitButton(account);
-                                            binding.submit.setEnabled(true);
-                                            binding.progress.setVisibility(View.INVISIBLE);
-                                        });
-                                    } else {
-                                        DeckLog.warn("Something went wrong while synchronizing the card " + cardRemoteId + " (cardRemoteId). Given fullCard is null.");
-                                        applyBrandToSubmitButton(account);
-                                        fallbackToBrowser(link);
-                                    }
-                                }));
-                            } else {
-                                DeckLog.warn("Given localBoardId for cardRemoteId " + cardRemoteId + " is null.");
-                                applyBrandToSubmitButton(account);
-                                fallbackToBrowser(link);
-                            }
-                        }));
-                    } else {
-                        DeckLog.warn("Given account for " + accountString + " is null.");
-                        fallbackToBrowser(link);
-                    }
-                }));
-            } catch (NumberFormatException e) {
-                DeckLog.logError(e);
+        if (ids.length == 2) {
+            if (cardRemoteIdString != null) {
+                try {
+                    final int cardRemoteId = Integer.parseInt(cardRemoteIdString);
+                    observeOnce(viewModel.readAccount(accountString), this, (account -> {
+                        if (account != null) {
+                            viewModel.setAccount(account.getName());
+                            DeckLog.verbose("account: " + account);
+                            observeOnce(viewModel.getBoardByRemoteId(account.getId(), ids[0]), PushNotificationActivity.this, (board -> {
+                                DeckLog.verbose("BoardLocalId " + board);
+                                if (board != null) {
+                                    observeOnce(viewModel.getCardByRemoteID(account.getId(), cardRemoteId), PushNotificationActivity.this, (card -> {
+                                        DeckLog.verbose("Card: " + card);
+                                        if (card != null) {
+                                            viewModel.synchronizeCard(new IResponseCallback<Boolean>(account) {
+                                                @Override
+                                                public void onResponse(Boolean response) {
+                                                    openCardOnSubmit(account, board.getLocalId(), card.getLocalId());
+                                                }
+
+                                                @Override
+                                                public void onError(Throwable throwable) {
+                                                    super.onError(throwable);
+                                                    openCardOnSubmit(account, board.getLocalId(), card.getLocalId());
+                                                }
+                                            }, card);
+                                        } else {
+                                            DeckLog.info("Card is not yet available locally. Synchronize board with localId " + board);
+
+                                            viewModel.synchronizeBoard(new IResponseCallback<Boolean>(account) {
+                                                @Override
+                                                public void onResponse(Boolean response) {
+                                                    runOnUiThread(() -> {
+                                                        observeOnce(viewModel.getCardByRemoteID(account.getId(), cardRemoteId), PushNotificationActivity.this, (card -> {
+                                                            DeckLog.verbose("Card: " + card);
+                                                            if (card != null) {
+                                                                openCardOnSubmit(account, board.getLocalId(), card.getLocalId());
+                                                            } else {
+                                                                DeckLog.warn("Something went wrong while synchronizing the card " + cardRemoteId + " (cardRemoteId). Given fullCard is null.");
+                                                                applyBrandToSubmitButton(account);
+                                                                fallbackToBrowser(link);
+                                                            }
+                                                        }));
+                                                    });
+                                                }
+
+                                                @Override
+                                                public void onError(Throwable throwable) {
+                                                    super.onError(throwable);
+                                                    DeckLog.warn("Something went wrong while synchronizing the board with localId " + board + ".");
+                                                    applyBrandToSubmitButton(account);
+                                                    fallbackToBrowser(link);
+                                                }
+                                            }, board.getLocalId());
+                                        }
+                                    }));
+                                } else {
+                                    DeckLog.warn("Given localBoardId for cardRemoteId " + cardRemoteId + " is null.");
+                                    applyBrandToSubmitButton(account);
+                                    fallbackToBrowser(link);
+                                }
+                            }));
+                        } else {
+                            DeckLog.warn("Given account for " + accountString + " is null.");
+                            fallbackToBrowser(link);
+                        }
+                    }));
+                } catch (NumberFormatException e) {
+                    DeckLog.logError(e);
+                    fallbackToBrowser(link);
+                }
+            } else {
+                DeckLog.warn(KEY_CARD_REMOTE_ID + " is null.");
                 fallbackToBrowser(link);
             }
         } else {
-            DeckLog.warn(KEY_CARD_REMOTE_ID + " is null.");
+            DeckLog.warn("Link does not contain two IDs (expected one board id and one card id): " + link);
             fallbackToBrowser(link);
         }
     }
 
+    private void openCardOnSubmit(@NonNull Account account, long boardLocalId, long cardlocalId) {
+        runOnUiThread(() -> {
+            binding.submit.setOnClickListener((v) -> launchEditActivity(account, boardLocalId, cardlocalId));
+            binding.submit.setText(R.string.simple_open);
+            applyBrandToSubmitButton(account);
+            binding.submit.setEnabled(true);
+            binding.progress.setVisibility(View.INVISIBLE);
+        });
+    }
+
     /**
      * If anything goes wrong and we cannot open the card directly, we fall back to open the given link in the webbrowser
      */
@@ -146,10 +193,13 @@ public class PushNotificationActivity extends AppCompatActivity {
         return true;
     }
 
+    // TODO implement Branded interface
+    // TODO apply branding based on board color
     public void applyBrandToSubmitButton(@NonNull Account account) {
+        @ColorInt final int mainColor = account.getColor();
         try {
-            binding.submit.setBackgroundColor(parseColor(account.getColor()));
-            binding.submit.setTextColor(parseColor(account.getTextColor()));
+            binding.submit.setBackgroundColor(mainColor);
+            binding.submit.setTextColor(ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(mainColor));
         } catch (Throwable t) {
             DeckLog.logError(t);
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/PushNotificationViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/PushNotificationViewModel.java
new file mode 100644
index 000000000..d15b412f4
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/PushNotificationViewModel.java
@@ -0,0 +1,52 @@
+package it.niedermann.nextcloud.deck.ui;
+
+import android.app.Application;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+
+import com.nextcloud.android.sso.helper.SingleAccountHelper;
+
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Board;
+import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+
+public class PushNotificationViewModel extends AndroidViewModel {
+
+    private final SyncManager readAccountSyncManager;
+    private SyncManager accountSpecificSyncManager;
+
+    public PushNotificationViewModel(@NonNull Application application) {
+        super(application);
+        this.readAccountSyncManager = new SyncManager(application);
+    }
+
+    public LiveData<Account> readAccount(@Nullable String name) {
+        return readAccountSyncManager.readAccount(name);
+    }
+
+    public void setAccount(@NonNull String accountName) {
+        SingleAccountHelper.setCurrentAccount(getApplication(), accountName);
+        accountSpecificSyncManager = new SyncManager(getApplication());
+    }
+
+    public LiveData<Board> getBoardByRemoteId(long accountId, long remoteId) {
+        return accountSpecificSyncManager.getBoardByRemoteId(accountId, remoteId);
+    }
+
+    public LiveData<Card> getCardByRemoteID(long accountId, long remoteId) {
+        return accountSpecificSyncManager.getCardByRemoteID(accountId, remoteId);
+    }
+
+    public void synchronizeCard(@NonNull IResponseCallback<Boolean> responseCallback, Card card) {
+        accountSpecificSyncManager.synchronizeCard(responseCallback, card);
+    }
+
+    public void synchronizeBoard(@NonNull IResponseCallback<Boolean> responseCallback, long localBoadId) {
+        accountSpecificSyncManager.synchronizeBoard(responseCallback, localBoadId);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutFragmentLicenseTab.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutFragmentLicenseTab.java
index c00ff212a..0bd92bc78 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutFragmentLicenseTab.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutFragmentLicenseTab.java
@@ -14,13 +14,13 @@ import androidx.annotation.NonNull;
 import androidx.core.content.ContextCompat;
 import androidx.core.graphics.drawable.DrawableCompat;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.FragmentAboutLicenseTabBinding;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedFragment;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
 
 import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
-import static it.niedermann.nextcloud.deck.util.ColorUtil.contrastRatioIsSufficientBigAreas;
+import static it.niedermann.nextcloud.deck.util.DeckColorUtil.contrastRatioIsSufficientBigAreas;
 import static it.niedermann.nextcloud.deck.util.SpannableUtil.setTextWithURL;
 
 public class AboutFragmentLicenseTab extends BrandedFragment {
@@ -42,6 +42,6 @@ public class AboutFragmentLicenseTab extends BrandedFragment {
                 ? mainColor
                 : isDarkTheme(requireContext()) ? Color.WHITE : Color.BLACK;
         DrawableCompat.setTintList(binding.aboutAppLicenseButton.getBackground(), ColorStateList.valueOf(finalMainColor));
-        binding.aboutAppLicenseButton.setTextColor(ColorUtil.getForegroundColorForBackgroundColor(finalMainColor));
+        binding.aboutAppLicenseButton.setTextColor(ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(finalMainColor));
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/accountswitcher/AccountSwitcherDialog.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/accountswitcher/AccountSwitcherDialog.java
index 592f2e8cc..744498c4a 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/accountswitcher/AccountSwitcherDialog.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/accountswitcher/AccountSwitcherDialog.java
@@ -1,7 +1,6 @@
 package it.niedermann.nextcloud.deck.ui.accountswitcher;
 
 import android.app.Dialog;
-import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Bundle;
@@ -16,43 +15,37 @@ import com.bumptech.glide.request.RequestOptions;
 import com.nextcloud.android.sso.AccountImporter;
 import com.nextcloud.android.sso.exceptions.AndroidGetAccountsPermissionNotGranted;
 import com.nextcloud.android.sso.exceptions.NextcloudFilesAppNotInstalledException;
+import com.nextcloud.android.sso.ui.UiExceptionManager;
 
+import it.niedermann.android.util.DimensionUtil;
+import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.DialogAccountSwitcherBinding;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 import it.niedermann.nextcloud.deck.ui.MainViewModel;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
 import it.niedermann.nextcloud.deck.ui.manageaccounts.ManageAccountsActivity;
-import it.niedermann.nextcloud.deck.util.ExceptionUtil;
 
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 import static it.niedermann.nextcloud.deck.ui.MainActivity.ACTIVITY_MANAGE_ACCOUNTS;
-import static it.niedermann.nextcloud.deck.util.DimensionUtil.dpToPx;
 
 public class AccountSwitcherDialog extends BrandedDialogFragment {
 
     private AccountSwitcherAdapter adapter;
-    private SyncManager syncManager;
     private DialogAccountSwitcherBinding binding;
     private MainViewModel viewModel;
 
-    @Override
-    public void onAttach(@NonNull Context context) {
-        super.onAttach(context);
-        viewModel = new ViewModelProvider(requireActivity()).get(MainViewModel.class);
-        syncManager = new SyncManager(requireActivity());
-    }
-
     @NonNull
     @Override
     public Dialog onCreateDialog(Bundle savedInstanceState) {
         binding = DialogAccountSwitcherBinding.inflate(requireActivity().getLayoutInflater());
+        viewModel = new ViewModelProvider(requireActivity()).get(MainViewModel.class);
+
         binding.accountName.setText(viewModel.getCurrentAccount().getUserName());
         binding.accountHost.setText(Uri.parse(viewModel.getCurrentAccount().getUrl()).getHost());
         binding.check.setSelected(true);
 
         Glide.with(requireContext())
-                .load(viewModel.getCurrentAccount().getAvatarUrl(dpToPx(binding.currentAccountItemAvatar.getContext(), R.dimen.avatar_size)))
+                .load(viewModel.getCurrentAccount().getAvatarUrl(DimensionUtil.INSTANCE.dpToPx(binding.currentAccountItemAvatar.getContext(), R.dimen.avatar_size)))
                 .placeholder(R.drawable.ic_baseline_account_circle_24)
                 .error(R.drawable.ic_baseline_account_circle_24)
                 .apply(RequestOptions.circleCropTransform())
@@ -65,7 +58,7 @@ public class AccountSwitcherDialog extends BrandedDialogFragment {
             dismiss();
         }));
 
-        observeOnce(syncManager.readAccounts(), requireActivity(), (accounts) -> {
+        observeOnce(viewModel.readAccounts(), requireActivity(), (accounts) -> {
             accounts.remove(viewModel.getCurrentAccount());
             adapter.setAccounts(accounts);
         });
@@ -76,7 +69,10 @@ public class AccountSwitcherDialog extends BrandedDialogFragment {
             try {
                 AccountImporter.pickNewAccount(requireActivity());
             } catch (NextcloudFilesAppNotInstalledException e) {
-                ExceptionUtil.handleNextcloudFilesAppNotInstalledException(requireContext(), e);
+                UiExceptionManager.showDialogForException(requireContext(), e);
+                DeckLog.warn("=============================================================");
+                DeckLog.warn("Nextcloud app is not installed. Cannot choose account");
+                DeckLog.logError(e);
             } catch (AndroidGetAccountsPermissionNotGranted e) {
                 AccountImporter.requestAndroidAccountPermissionsAndPickAccount(requireActivity());
             }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/accountswitcher/AccountSwitcherViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/accountswitcher/AccountSwitcherViewHolder.java
index 9c93c422e..a60b6a0ea 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/accountswitcher/AccountSwitcherViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/accountswitcher/AccountSwitcherViewHolder.java
@@ -10,12 +10,11 @@ import androidx.recyclerview.widget.RecyclerView;
 import com.bumptech.glide.Glide;
 import com.bumptech.glide.request.RequestOptions;
 
-import it.niedermann.android.glidesso.SingleSignOnUrl;
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemAccountChooseBinding;
 import it.niedermann.nextcloud.deck.model.Account;
-
-import static it.niedermann.nextcloud.deck.util.DimensionUtil.dpToPx;
+import it.niedermann.nextcloud.sso.glide.SingleSignOnUrl;
 
 public class AccountSwitcherViewHolder extends RecyclerView.ViewHolder {
 
@@ -30,7 +29,7 @@ public class AccountSwitcherViewHolder extends RecyclerView.ViewHolder {
         binding.accountName.setText(account.getUserName());
         binding.accountHost.setText(Uri.parse(account.getUrl()).getHost());
         Glide.with(itemView.getContext())
-                .load(new SingleSignOnUrl(account.getName(), account.getAvatarUrl(dpToPx(binding.accountItemAvatar.getContext(), R.dimen.avatar_size))))
+                .load(new SingleSignOnUrl(account.getName(), account.getAvatarUrl(DimensionUtil.INSTANCE.dpToPx(binding.accountItemAvatar.getContext(), R.dimen.avatar_size))))
                 .placeholder(R.drawable.ic_baseline_account_circle_24)
                 .error(R.drawable.ic_baseline_account_circle_24)
                 .apply(RequestOptions.circleCropTransform())
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardViewHolder.java
index 5ab94b4f6..30f1e5d49 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardViewHolder.java
@@ -6,6 +6,7 @@ import android.view.MenuItem;
 import android.view.View;
 
 import androidx.appcompat.widget.PopupMenu;
+import androidx.core.content.ContextCompat;
 import androidx.core.util.Consumer;
 import androidx.fragment.app.FragmentManager;
 import androidx.recyclerview.widget.RecyclerView;
@@ -30,14 +31,13 @@ public class ArchivedBoardViewHolder extends RecyclerView.ViewHolder {
 
     void bind(boolean isSupportedVersion, Board board, FragmentManager fragmentManager, Consumer<Board> dearchiveBoardListener) {
         final Context context = itemView.getContext();
-        binding.boardIcon.setImageDrawable(ViewUtil.getTintedImageView(binding.boardIcon.getContext(), R.drawable.circle_grey600_36dp, "#" + board.getColor()));
+        binding.boardIcon.setImageDrawable(ViewUtil.getTintedImageView(binding.boardIcon.getContext(), R.drawable.circle_grey600_36dp, board.getColor()));
         binding.boardMenu.setVisibility(View.GONE);
         binding.boardTitle.setText(board.getTitle());
         if (isSupportedVersion) {
             if (board.isPermissionManage()) {
                 binding.boardMenu.setVisibility(View.VISIBLE);
-                binding.boardMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_menu, R.color.grey600));
-
+                binding.boardMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_menu, ContextCompat.getColor(context, R.color.grey600)));
                 binding.boardMenu.setOnClickListener((v) -> {
                     PopupMenu popup = new PopupMenu(context, binding.boardMenu);
                     popup.getMenuInflater().inflate(R.menu.archived_board_menu, popup.getMenu());
@@ -47,28 +47,27 @@ public class ArchivedBoardViewHolder extends RecyclerView.ViewHolder {
                     }
                     popup.setOnMenuItemClickListener((MenuItem item) -> {
                         final String editBoard = context.getString(R.string.edit_board);
-                        switch (item.getItemId()) {
-                            case SHARE_BOARD_ID:
-                                AccessControlDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, AccessControlDialogFragment.class.getSimpleName());
-                                return true;
-                            case R.id.edit_board:
-                                EditBoardDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, editBoard);
-                                return true;
-                            case R.id.dearchive_board:
-                                dearchiveBoardListener.accept(board);
-                                return true;
-                            case R.id.delete_board:
-                                DeleteBoardDialogFragment.newInstance(board).show(fragmentManager, DeleteBoardDialogFragment.class.getSimpleName());
-                                return true;
-                            default:
-                                return false;
+                        int itemId = item.getItemId();
+                        if (itemId == SHARE_BOARD_ID) {
+                            AccessControlDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, AccessControlDialogFragment.class.getSimpleName());
+                            return true;
+                        } else if (itemId == R.id.edit_board) {
+                            EditBoardDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, editBoard);
+                            return true;
+                        } else if (itemId == R.id.dearchive_board) {
+                            dearchiveBoardListener.accept(board);
+                            return true;
+                        } else if (itemId == R.id.delete_board) {
+                            DeleteBoardDialogFragment.newInstance(board).show(fragmentManager, DeleteBoardDialogFragment.class.getSimpleName());
+                            return true;
                         }
+                        return false;
                     });
                     popup.show();
                 });
             } else if (board.isPermissionShare()) {
                 binding.boardMenu.setVisibility(View.VISIBLE);
-                binding.boardMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_share_grey600_18dp, R.color.grey600));
+                binding.boardMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_share_grey600_18dp, ContextCompat.getColor(context, R.color.grey600)));
                 binding.boardMenu.setOnClickListener((v) -> AccessControlDialogFragment.newInstance(board.getLocalId()).show(fragmentManager, AccessControlDialogFragment.class.getSimpleName()));
             }
             binding.boardMenu.setVisibility(View.VISIBLE);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardsActvitiy.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardsActvitiy.java
index 7c3a2d23c..d6d9cac1e 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardsActvitiy.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedboards/ArchivedBoardsActvitiy.java
@@ -15,13 +15,17 @@ import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Board;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 import it.niedermann.nextcloud.deck.ui.MainViewModel;
 import it.niedermann.nextcloud.deck.ui.board.ArchiveBoardListener;
 import it.niedermann.nextcloud.deck.ui.board.DeleteBoardListener;
 import it.niedermann.nextcloud.deck.ui.board.EditBoardListener;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedActivity;
+import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
 
+import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
+
 public class ArchivedBoardsActvitiy extends BrandedActivity implements DeleteBoardListener, EditBoardListener, ArchiveBoardListener {
 
     private static final String BUNDLE_KEY_ACCOUNT = "accountId";
@@ -29,7 +33,6 @@ public class ArchivedBoardsActvitiy extends BrandedActivity implements DeleteBoa
     private MainViewModel viewModel;
     private ActivityArchivedBinding binding;
     private ArchivedBoardsAdapter adapter;
-    private SyncManager syncManager;
 
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
@@ -54,12 +57,18 @@ public class ArchivedBoardsActvitiy extends BrandedActivity implements DeleteBoa
 
         viewModel = new ViewModelProvider(this).get(MainViewModel.class);
         viewModel.setCurrentAccount(account);
-        syncManager = new SyncManager(this);
 
-        adapter = new ArchivedBoardsAdapter(viewModel.isCurrentAccountIsSupportedVersion(), getSupportFragmentManager(), (board) -> syncManager.dearchiveBoard(board));
+        adapter = new ArchivedBoardsAdapter(viewModel.isCurrentAccountIsSupportedVersion(), getSupportFragmentManager(), (board) -> {
+            final WrappedLiveData<FullBoard> liveData = viewModel.dearchiveBoard(board);
+            observeOnce(liveData, this, (fullBoard) -> {
+                if (liveData.hasError()) {
+                    ExceptionDialogFragment.newInstance(liveData.getError(), viewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                }
+            });
+        });
         binding.recyclerView.setAdapter(adapter);
 
-        syncManager.getBoards(account.getId(), true).observe(this, (boards) -> {
+        viewModel.getBoards(account.getId(), true).observe(this, (boards) -> {
             viewModel.setCurrentAccountHasArchivedBoards(boards != null && boards.size() > 0);
             adapter.setBoards(boards == null ? Collections.emptyList() : boards);
         });
@@ -80,16 +89,36 @@ public class ArchivedBoardsActvitiy extends BrandedActivity implements DeleteBoa
 
     @Override
     public void onBoardDeleted(Board board) {
-        syncManager.deleteBoard(board);
+        final WrappedLiveData<Void> deleteLiveData = viewModel.deleteBoard(board);
+        observeOnce(deleteLiveData, this, (next) -> {
+            if (deleteLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteLiveData.getError())) {
+                ExceptionDialogFragment.newInstance(deleteLiveData.getError(), viewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
     }
 
     @Override
     public void onUpdateBoard(FullBoard fullBoard) {
-        syncManager.updateBoard(fullBoard);
+        final WrappedLiveData<FullBoard> updateLiveData = viewModel.updateBoard(fullBoard);
+        observeOnce(updateLiveData, this, (next) -> {
+            if (updateLiveData.hasError()) {
+                ExceptionDialogFragment.newInstance(updateLiveData.getError(), viewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
     }
 
     @Override
     public void onArchive(Board board) {
-        syncManager.dearchiveBoard(board);
+        final WrappedLiveData<FullBoard> liveData = viewModel.dearchiveBoard(board);
+        observeOnce(liveData, this, (fullBoard) -> {
+            if (liveData.hasError()) {
+                ExceptionDialogFragment.newInstance(liveData.getError(), viewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
+    }
+
+    @Override
+    public void onClone(Board board) {
+
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedcards/ArchivedCardsActvitiy.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedcards/ArchivedCardsActvitiy.java
index ed2ee7097..b3533528e 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedcards/ArchivedCardsActvitiy.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedcards/ArchivedCardsActvitiy.java
@@ -6,12 +6,15 @@ import android.os.Bundle;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.lifecycle.ViewModelProvider;
 
 import it.niedermann.nextcloud.deck.databinding.ActivityArchivedBinding;
 import it.niedermann.nextcloud.deck.model.Account;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper;
+import it.niedermann.nextcloud.deck.ui.MainViewModel;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedActivity;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
+import it.niedermann.nextcloud.deck.ui.pickstack.PickStackViewModel;
 
 public class ArchivedCardsActvitiy extends BrandedActivity {
 
@@ -21,7 +24,8 @@ public class ArchivedCardsActvitiy extends BrandedActivity {
 
     private ActivityArchivedBinding binding;
     private ArchivedCardsAdapter adapter;
-    private SyncManager syncManager;
+    private MainViewModel viewModel;
+    private PickStackViewModel pickStackViewModel;
 
     private Account account;
     private long boardId;
@@ -50,16 +54,20 @@ public class ArchivedCardsActvitiy extends BrandedActivity {
         }
 
         binding = ActivityArchivedBinding.inflate(getLayoutInflater());
+        viewModel = new ViewModelProvider(this).get(MainViewModel.class);
+        pickStackViewModel = new ViewModelProvider(this).get(PickStackViewModel.class);
+
         setContentView(binding.getRoot());
         setSupportActionBar(binding.toolbar);
 
-        syncManager = new SyncManager(this);
+        viewModel.setCurrentAccount(account);
+        LiveDataHelper.observeOnce(viewModel.getFullBoardById(account.getId(), boardId), this, (fullBoard) -> {
+            viewModel.setCurrentBoard(fullBoard.getBoard());
 
-        adapter = new ArchivedCardsAdapter(this, getSupportFragmentManager(), account, boardId, false, syncManager, this);
-        binding.recyclerView.setAdapter(adapter);
+            adapter = new ArchivedCardsAdapter(this, getSupportFragmentManager(), viewModel, this);
+            binding.recyclerView.setAdapter(adapter);
 
-        syncManager.getArchivedFullCardsForBoard(account.getId(), boardId).observe(this, (fullCards) -> {
-            adapter.setCardList(fullCards);
+            viewModel.getArchivedFullCardsForBoard(account.getId(), boardId).observe(this, (fullCards) -> adapter.setCardList(fullCards));
         });
 
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedcards/ArchivedCardsAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedcards/ArchivedCardsAdapter.java
index e6abf0ccc..b5034ebfa 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedcards/ArchivedCardsAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/archivedcards/ArchivedCardsAdapter.java
@@ -1,67 +1,55 @@
 package it.niedermann.nextcloud.deck.ui.archivedcards;
 
 import android.content.Context;
-import android.view.Menu;
 import android.view.MenuItem;
-import android.view.View;
-import android.widget.PopupMenu;
 
 import androidx.annotation.NonNull;
 import androidx.fragment.app.FragmentManager;
 import androidx.lifecycle.LifecycleOwner;
 
-import org.jetbrains.annotations.NotNull;
-
 import it.niedermann.nextcloud.deck.R;
-import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
+import it.niedermann.nextcloud.deck.ui.MainViewModel;
+import it.niedermann.nextcloud.deck.ui.card.AbstractCardViewHolder;
 import it.niedermann.nextcloud.deck.ui.card.CardAdapter;
-import it.niedermann.nextcloud.deck.ui.card.ItemCardViewHolder;
+import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
+
+import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 
 public class ArchivedCardsAdapter extends CardAdapter {
 
     @SuppressWarnings("WeakerAccess")
-    public ArchivedCardsAdapter(@NonNull Context context, @NonNull FragmentManager fragmentManager, @NonNull Account account, long boardId, boolean canEdit, @NonNull SyncManager syncManager, @NonNull LifecycleOwner lifecycleOwner) {
-        super(context, fragmentManager, account, boardId, 0L, 0L, canEdit, syncManager, lifecycleOwner, null);
+    public ArchivedCardsAdapter(@NonNull Context context, @NonNull FragmentManager fragmentManager, @NonNull MainViewModel viewModel, @NonNull LifecycleOwner lifecycleOwner) {
+        super(context, fragmentManager, 0L, viewModel, lifecycleOwner, null);
     }
 
     @Override
-    public void onBindViewHolder(@NonNull ItemCardViewHolder viewHolder, int position) {
-        super.onBindViewHolder(viewHolder, position);
-        viewHolder.binding.card.setOnClickListener(null);
-        viewHolder.binding.card.setOnLongClickListener(null);
-    }
-
-    protected void onOverflowIconClicked(@NotNull View view, FullCard card) {
-        final Context context = view.getContext();
-        final PopupMenu popup = new PopupMenu(context, view);
-        popup.inflate(R.menu.card_menu);
-        prepareOptionsMenu(popup.getMenu(), card);
-
-        popup.setOnMenuItemClickListener(item -> optionsItemSelected(context, item, card));
-        popup.show();
-    }
-
-    protected void prepareOptionsMenu(Menu menu, @NotNull FullCard card) {
-        // Nothing to do
+    public void onBindViewHolder(@NonNull AbstractCardViewHolder viewHolder, int position) {
+        viewHolder.bind(cardList.get(position), mainViewModel.getCurrentAccount(), mainViewModel.getCurrentBoardRemoteId(), false, R.menu.archived_card_menu, this, counterMaxValue, mainColor);
     }
 
-    protected boolean optionsItemSelected(@NonNull Context context, @NotNull MenuItem item, FullCard fullCard) {
-        switch (item.getItemId()) {
-            case R.id.action_card_dearchive: {
-                // TODO error handling
-                new Thread(() -> syncManager.dearchiveCard(fullCard)).start();
-                return true;
-            }
-            case R.id.action_card_delete: {
-                // TODO error handling
-                syncManager.deleteCard(fullCard.getCard());
-                return true;
-            }
-            default: {
-                return false;
-            }
+    @Override
+    public boolean onCardOptionsItemSelected(@NonNull MenuItem menuItem, @NonNull FullCard fullCard) {
+        int itemId = menuItem.getItemId();
+        if (itemId == R.id.action_card_dearchive) {
+            final WrappedLiveData<FullCard> liveData = mainViewModel.dearchiveCard(fullCard);
+            observeOnce(liveData, lifecycleOwner, (next) -> {
+                if (liveData.hasError()) {
+                    ExceptionDialogFragment.newInstance(liveData.getError(), mainViewModel.getCurrentAccount()).show(fragmentManager, ExceptionDialogFragment.class.getSimpleName());
+                }
+            });
+            return true;
+        } else if (itemId == R.id.action_card_delete) {
+            final WrappedLiveData<Void> liveData = mainViewModel.deleteCard(fullCard.getCard());
+            observeOnce(liveData, lifecycleOwner, (next) -> {
+                if (liveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(liveData.getError())) {
+                    ExceptionDialogFragment.newInstance(liveData.getError(), mainViewModel.getCurrentAccount()).show(fragmentManager, ExceptionDialogFragment.class.getSimpleName());
+                }
+            });
+            return true;
         }
+        return super.onCardOptionsItemSelected(menuItem, fullCard);
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentAdapter.java
index 0794323ec..c7d32bd37 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentAdapter.java
@@ -1,43 +1,31 @@
 package it.niedermann.nextcloud.deck.ui.attachments;
 
 import android.content.Context;
-import android.graphics.drawable.Drawable;
-import android.os.Build;
 import android.view.LayoutInflater;
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.fragment.app.FragmentActivity;
 import androidx.recyclerview.widget.RecyclerView;
 
-import com.bumptech.glide.Glide;
-import com.bumptech.glide.load.DataSource;
-import com.bumptech.glide.load.engine.GlideException;
-import com.bumptech.glide.request.RequestListener;
-import com.bumptech.glide.request.target.Target;
-
+import java.util.ArrayList;
 import java.util.List;
 
-import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentBinding;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
-import it.niedermann.nextcloud.deck.util.AttachmentUtil;
-import it.niedermann.nextcloud.deck.util.MimeTypeUtil;
 
 public class AttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHolder> {
 
     private final Account account;
     private final long cardRemoteId;
     @NonNull
-    private List<Attachment> attachments;
-    private Context context;
+    private final List<Attachment> attachments = new ArrayList<>();
 
     @SuppressWarnings("WeakerAccess")
     public AttachmentAdapter(@NonNull Account account, long cardRemoteId, @NonNull List<Attachment> attachments) {
         super();
-        this.attachments = attachments;
+        this.attachments.clear();
+        this.attachments.addAll(attachments);
         this.account = account;
         this.cardRemoteId = cardRemoteId;
     }
@@ -45,43 +33,13 @@ public class AttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHolder
     @NonNull
     @Override
     public AttachmentViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-        this.context = parent.getContext();
-        return new AttachmentViewHolder(ItemAttachmentBinding.inflate(LayoutInflater.from(context), parent, false));
+        final Context context = parent.getContext();
+        return new AttachmentViewHolder(context, ItemAttachmentBinding.inflate(LayoutInflater.from(context), parent, false));
     }
 
     @Override
     public void onBindViewHolder(@NonNull AttachmentViewHolder holder, int position) {
-        final Attachment attachment = attachments.get(position);
-        final String uri = AttachmentUtil.getRemoteUrl(account.getUrl(), cardRemoteId, attachment.getId());
-        if (MimeTypeUtil.isImage(attachment.getMimetype())) {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
-                holder.binding.preview.setTransitionName(context.getString(R.string.transition_attachment_preview, String.valueOf(attachment.getLocalId())));
-            }
-            holder.binding.preview.setImageResource(R.drawable.ic_image_grey600_24dp);
-            Glide.with(context)
-                    .load(uri)
-                    .listener(new RequestListener<Drawable>() {
-                        @Override
-                        public boolean onLoadFailed(@Nullable GlideException e, Object model,
-                                                    Target<Drawable> target, boolean isFirstResource) {
-                            if (context instanceof FragmentActivity) {
-                                ((FragmentActivity) context).supportStartPostponedEnterTransition();
-                            }
-                            return false;
-                        }
-
-                        @Override
-                        public boolean onResourceReady(Drawable resource, Object model,
-                                                       Target<Drawable> target, DataSource dataSource, boolean isFirstResource) {
-                            if (context instanceof FragmentActivity) {
-                                ((FragmentActivity) context).supportStartPostponedEnterTransition();
-                            }
-                            return false;
-                        }
-                    })
-                    .error(R.drawable.ic_image_grey600_24dp)
-                    .into(holder.binding.preview);
-        }
+        holder.bind(account, attachments.get(position), cardRemoteId);
     }
 
     @Override
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentViewHolder.java
index 584a57d1d..6f4fe3c74 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentViewHolder.java
@@ -1,15 +1,72 @@
 package it.niedermann.nextcloud.deck.ui.attachments;
 
+import android.content.Context;
+import android.graphics.drawable.Drawable;
+import android.os.Build;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.FragmentActivity;
 import androidx.recyclerview.widget.RecyclerView;
 
+import com.bumptech.glide.Glide;
+import com.bumptech.glide.load.DataSource;
+import com.bumptech.glide.load.engine.GlideException;
+import com.bumptech.glide.request.RequestListener;
+import com.bumptech.glide.request.target.Target;
+
+import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Attachment;
+import it.niedermann.nextcloud.deck.util.AttachmentUtil;
+import it.niedermann.nextcloud.deck.util.MimeTypeUtil;
 
 public class AttachmentViewHolder extends RecyclerView.ViewHolder {
-    public ItemAttachmentBinding binding;
+    @NonNull
+    private final Context parentContext;
+    @NonNull
+    private final ItemAttachmentBinding binding;
 
     @SuppressWarnings("WeakerAccess")
-    public AttachmentViewHolder(ItemAttachmentBinding binding) {
+    public AttachmentViewHolder(@NonNull Context parentContext, @NonNull ItemAttachmentBinding binding) {
         super(binding.getRoot());
+        this.parentContext = parentContext;
         this.binding = binding;
     }
+
+    public void bind(@NonNull Account account, @NonNull Attachment attachment, long cardRemoteId) {
+        if (MimeTypeUtil.isImage(attachment.getMimetype())) {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+                binding.preview.setTransitionName(parentContext.getString(R.string.transition_attachment_preview, String.valueOf(attachment.getLocalId())));
+            }
+            binding.preview.setImageResource(R.drawable.ic_image_grey600_24dp);
+            binding.preview.post(() -> {
+                final String uri = AttachmentUtil.getThumbnailUrl(account.getServerDeckVersionAsObject(), account.getUrl(), cardRemoteId, attachment, binding.preview.getWidth());
+                Glide.with(parentContext)
+                        .load(uri)
+                        .listener(new RequestListener<Drawable>() {
+                            @Override
+                            public boolean onLoadFailed(@Nullable GlideException e, Object model,
+                                                        Target<Drawable> target, boolean isFirstResource) {
+                                if (parentContext instanceof FragmentActivity) {
+                                    ((FragmentActivity) parentContext).supportStartPostponedEnterTransition();
+                                }
+                                return false;
+                            }
+
+                            @Override
+                            public boolean onResourceReady(Drawable resource, Object model,
+                                                           Target<Drawable> target, DataSource dataSource, boolean isFirstResource) {
+                                if (parentContext instanceof FragmentActivity) {
+                                    ((FragmentActivity) parentContext).supportStartPostponedEnterTransition();
+                                }
+                                return false;
+                            }
+                        })
+                        .error(R.drawable.ic_image_grey600_24dp)
+                        .into(binding.preview);
+            });
+        }
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentsActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentsActivity.java
index 98cfd4440..6618f7f72 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentsActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentsActivity.java
@@ -2,6 +2,7 @@ package it.niedermann.nextcloud.deck.ui.attachments;
 
 import android.content.Context;
 import android.content.Intent;
+import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.view.MotionEvent;
 import android.view.View;
@@ -9,6 +10,9 @@ import android.view.View;
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.app.SharedElementCallback;
+import androidx.core.content.ContextCompat;
+import androidx.core.graphics.drawable.DrawableCompat;
+import androidx.lifecycle.ViewModelProvider;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.viewpager2.widget.ViewPager2;
 
@@ -21,7 +25,6 @@ import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ActivityAttachmentsBinding;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
 import it.niedermann.nextcloud.deck.util.MimeTypeUtil;
 
@@ -32,6 +35,7 @@ public class AttachmentsActivity extends AppCompatActivity {
     private static final String BUNDLE_KEY_CURRENT_ATTACHMENT_LOCAL_ID = "currentAttachmenLocaltId";
 
     private ActivityAttachmentsBinding binding;
+    private AttachmentsViewModel viewModel;
     private ViewPager2.OnPageChangeCallback onPageChangeCallback;
 
     @Override
@@ -40,10 +44,15 @@ public class AttachmentsActivity extends AppCompatActivity {
         Thread.currentThread().setUncaughtExceptionHandler(new ExceptionHandler(this));
 
         binding = ActivityAttachmentsBinding.inflate(getLayoutInflater());
+        viewModel = new ViewModelProvider(this).get(AttachmentsViewModel.class);
+
         setContentView(binding.getRoot());
         supportPostponeEnterTransition();
 
         setSupportActionBar(binding.toolbar);
+        final Drawable navigationIcon = getResources().getDrawable(R.drawable.ic_arrow_back_white_24dp);
+        DrawableCompat.setTint(navigationIcon, ContextCompat.getColor(this, android.R.color.white));
+        binding.toolbar.setNavigationIcon(navigationIcon);
 
         final Bundle args = getIntent().getExtras();
         if (args == null || !args.containsKey(BUNDLE_KEY_ACCOUNT) || !args.containsKey(BUNDLE_KEY_CARD_ID)) {
@@ -58,8 +67,7 @@ public class AttachmentsActivity extends AppCompatActivity {
 
         long cardId = args.getLong(BUNDLE_KEY_CARD_ID);
 
-        final SyncManager syncManager = new SyncManager(this);
-        syncManager.getCardByLocalId(account.getId(), cardId).observe(this, fullCard -> {
+        viewModel.getFullCardWithProjectsByLocalId(account.getId(), cardId).observe(this, fullCard -> {
             final List<Attachment> attachments = new ArrayList<>();
             for (Attachment a : fullCard.getAttachments()) {
                 if (MimeTypeUtil.isImage(a.getMimetype())) {
@@ -67,7 +75,7 @@ public class AttachmentsActivity extends AppCompatActivity {
                 }
             }
             if (fullCard.getAttachments().size() == 0) {
-                DeckLog.logError(new IllegalStateException(AttachmentsActivity.class.getSimpleName() + " called, but card " + fullCard.getLocalId() + "has no attachments"));
+                DeckLog.logError(new IllegalStateException(AttachmentsActivity.class.getSimpleName() + " called, but card " + fullCard.getCard().getTitle() + " has no attachments"));
                 supportFinishAfterTransition();
                 return;
             }
@@ -79,7 +87,7 @@ public class AttachmentsActivity extends AppCompatActivity {
                     binding.toolbar.setTitle(attachments.get(position).getBasename());
                 }
             };
-            RecyclerView.Adapter adapter = new AttachmentAdapter(account, fullCard.getId(), attachments);
+            RecyclerView.Adapter<AttachmentViewHolder> adapter = new AttachmentAdapter(account, fullCard.getId(), attachments);
             binding.viewPager.setAdapter(adapter);
             binding.viewPager.registerOnPageChangeCallback(onPageChangeCallback);
 
@@ -104,7 +112,7 @@ public class AttachmentsActivity extends AppCompatActivity {
                     long currentAttachmentLocalId = attachments.get(binding.viewPager.getCurrentItem()).getLocalId();
                     String transitionKey = getString(R.string.transition_attachment_preview, String.valueOf(currentAttachmentLocalId));
                     if (transitionKey.equals(names.get(0))) {
-                        sharedElements.put(transitionKey, binding.viewPager.getRootView().findViewById(R.id.preview)
+                        sharedElements.put(transitionKey, binding.viewPager.getRootView().findViewById(R.id.avatar)
                         );
                     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentsViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentsViewModel.java
new file mode 100644
index 000000000..87a17470c
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/attachments/AttachmentsViewModel.java
@@ -0,0 +1,25 @@
+package it.niedermann.nextcloud.deck.ui.attachments;
+
+import android.app.Application;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+
+import it.niedermann.nextcloud.deck.model.full.FullCardWithProjects;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+
+@SuppressWarnings("WeakerAccess")
+public class AttachmentsViewModel extends AndroidViewModel {
+
+    private final SyncManager syncManager;
+
+    public AttachmentsViewModel(@NonNull Application application) {
+        super(application);
+        this.syncManager = new SyncManager(application);
+    }
+
+    public LiveData<FullCardWithProjects> getFullCardWithProjectsByLocalId(long accountId, long cardLocalId) {
+        return syncManager.getFullCardWithProjectsByLocalId(accountId, cardLocalId);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/ArchiveBoardListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/ArchiveBoardListener.java
index b7e27aa97..ff0d3e941 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/ArchiveBoardListener.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/ArchiveBoardListener.java
@@ -4,4 +4,5 @@ import it.niedermann.nextcloud.deck.model.Board;
 
 public interface ArchiveBoardListener {
     void onArchive(Board board);
+    void onClone(Board board);
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/BoardAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/BoardAdapter.java
index 7049cc16c..c9501ffa9 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/BoardAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/BoardAdapter.java
@@ -37,7 +37,7 @@ public class BoardAdapter extends ArrayAdapter<Board> {
         TextView boardName = convertView.findViewById(R.id.boardName);
         if (board != null) {
             boardName.setText(board.getTitle());
-            boardName.setCompoundDrawables(ViewUtil.getTintedImageView(context, R.drawable.circle_grey600_36dp, "#" + board.getColor()), null, null, null);
+            boardName.setCompoundDrawables(ViewUtil.getTintedImageView(context, R.drawable.circle_grey600_36dp, board.getColor()), null, null, null);
         } else {
             DeckLog.logError(new IllegalArgumentException("board at position " + position + "is null"));
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardDialogFragment.java
index e5d0a482b..9da836c4c 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardDialogFragment.java
@@ -7,13 +7,13 @@ import android.os.Bundle;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
+import androidx.core.content.ContextCompat;
 import androidx.fragment.app.DialogFragment;
 import androidx.lifecycle.ViewModelProvider;
 
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.DialogTextColorInputBinding;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 import it.niedermann.nextcloud.deck.ui.MainViewModel;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedAlertDialogBuilder;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
@@ -53,24 +53,24 @@ public class EditBoardDialogFragment extends BrandedDialogFragment {
         if (args != null && args.containsKey(KEY_BOARD_ID)) {
             dialogBuilder.setTitle(R.string.edit_board);
             dialogBuilder.setPositiveButton(R.string.simple_save, (dialog, which) -> {
-                this.fullBoard.board.setColor(binding.colorChooser.getSelectedColor().substring(1));
+                this.fullBoard.board.setColor(binding.colorChooser.getSelectedColor());
                 this.fullBoard.board.setTitle(binding.input.getText().toString());
-                editBoardListener.onUpdateBoard(fullBoard);
+                this.editBoardListener.onUpdateBoard(fullBoard);
             });
             final MainViewModel viewModel = new ViewModelProvider(requireActivity()).get(MainViewModel.class);
-            new SyncManager(requireActivity()).getFullBoardById(viewModel.getCurrentAccount().getId(), args.getLong(KEY_BOARD_ID)).observe(EditBoardDialogFragment.this, (FullBoard fb) -> {
+            viewModel.getFullBoardById(viewModel.getCurrentAccount().getId(), args.getLong(KEY_BOARD_ID)).observe(EditBoardDialogFragment.this, (FullBoard fb) -> {
                 if (fb.board != null) {
                     this.fullBoard = fb;
                     String title = this.fullBoard.getBoard().getTitle();
                     binding.input.setText(title);
                     binding.input.setSelection(title.length());
-                    binding.colorChooser.selectColor("#" + fullBoard.getBoard().getColor());
+                    binding.colorChooser.selectColor(fullBoard.getBoard().getColor());
                 }
             });
         } else {
             dialogBuilder.setTitle(R.string.add_board);
             dialogBuilder.setPositiveButton(R.string.simple_add, (dialog, which) -> editBoardListener.onCreateBoard(binding.input.getText().toString(), binding.colorChooser.getSelectedColor()));
-            binding.colorChooser.selectColor(String.format("#%06X", 0xFFFFFF & getResources().getColor(R.color.board_default_color)));
+            binding.colorChooser.selectColor(ContextCompat.getColor(requireContext(), R.color.board_default_color));
         }
 
         return dialogBuilder
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardListener.java
index ee9ba9b9d..9d8fcdbde 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardListener.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/EditBoardListener.java
@@ -1,11 +1,13 @@
 package it.niedermann.nextcloud.deck.ui.board;
 
+import androidx.annotation.ColorInt;
+
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
 
 public interface EditBoardListener {
     void onUpdateBoard(FullBoard fullBoard);
 
-    default void onCreateBoard(String title, String color) {
+    default void onCreateBoard(String title, @ColorInt int color) {
         // Creating board is not necessary
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/accesscontrol/AccessControlAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/accesscontrol/AccessControlAdapter.java
index e5a50d9f4..0a1281fae 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/accesscontrol/AccessControlAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/accesscontrol/AccessControlAdapter.java
@@ -10,6 +10,7 @@ import android.view.ViewGroup;
 import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.appcompat.widget.SwitchCompat;
+import androidx.core.content.ContextCompat;
 import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.recyclerview.widget.RecyclerView;
 
@@ -51,7 +52,7 @@ public class AccessControlAdapter extends RecyclerView.Adapter<RecyclerView.View
         this.account = account;
         this.accessControlChangedListener = accessControlChangedListener;
         this.context = context;
-        this.mainColor = context.getResources().getColor(R.color.primary);
+        this.mainColor = ContextCompat.getColor(context, R.color.primary);
         setHasStableIds(true);
     }
 
@@ -172,9 +173,9 @@ public class AccessControlAdapter extends RecyclerView.Adapter<RecyclerView.View
         final int finalMainColor = getSecondaryForegroundColorDependingOnTheme(context, mainColor);
         DrawableCompat.setTintList(switchCompat.getThumbDrawable(), new ColorStateList(
                 new int[][]{new int[]{android.R.attr.state_checked}, new int[]{}},
-                new int[]{finalMainColor, context.getResources().getColor(R.color.fg_secondary)}
+                new int[]{finalMainColor, ContextCompat.getColor(context, R.color.fg_secondary)}
         ));
-        final int trackColor = context.getResources().getColor(R.color.fg_secondary);
+        final int trackColor = ContextCompat.getColor(context, R.color.fg_secondary);
         final int lightTrackColor = Color.argb(77, Color.red(trackColor), Color.green(trackColor), Color.blue(trackColor));
         final int lightTrackColorChecked = Color.argb(77, Color.red(finalMainColor), Color.green(finalMainColor), Color.blue(finalMainColor));
         DrawableCompat.setTintList(switchCompat.getTrackDrawable(), new ColorStateList(
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/accesscontrol/AccessControlDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/accesscontrol/AccessControlDialogFragment.java
index 33c0fe5b1..78ccd5333 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/accesscontrol/AccessControlDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/accesscontrol/AccessControlDialogFragment.java
@@ -43,7 +43,6 @@ public class AccessControlDialogFragment extends BrandedDialogFragment implement
     private static final String KEY_BOARD_ID = "board_id";
 
     private long boardId;
-    private SyncManager syncManager;
     private UserAutoCompleteAdapter userAutoCompleteAdapter;
     private AccessControlAdapter adapter;
 
@@ -75,10 +74,9 @@ public class AccessControlDialogFragment extends BrandedDialogFragment implement
         adapter = new AccessControlAdapter(viewModel.getCurrentAccount(), this, requireContext());
         binding.peopleList.setAdapter(adapter);
 
-        syncManager = new SyncManager(requireActivity());
-        syncManager.getFullBoardById(viewModel.getCurrentAccount().getId(), boardId).observe(this, (FullBoard fullBoard) -> {
+        viewModel.getFullBoardById(viewModel.getCurrentAccount().getId(), boardId).observe(this, (FullBoard fullBoard) -> {
             if (fullBoard != null) {
-                syncManager.getAccessControlByLocalBoardId(viewModel.getCurrentAccount().getId(), boardId).observe(this, (List<AccessControl> accessControlList) -> {
+                viewModel.getAccessControlByLocalBoardId(viewModel.getCurrentAccount().getId(), boardId).observe(this, (List<AccessControl> accessControlList) -> {
                     final AccessControl ownerControl = new AccessControl();
                     ownerControl.setLocalId(HEADER_ITEM_LOCAL_ID);
                     ownerControl.setUser(fullBoard.getOwner());
@@ -103,15 +101,20 @@ public class AccessControlDialogFragment extends BrandedDialogFragment implement
 
     @Override
     public void updateAccessControl(AccessControl accessControl) {
-        syncManager.updateAccessControl(accessControl);
+        WrappedLiveData<AccessControl> updateLiveData = viewModel.updateAccessControl(accessControl);
+        observeOnce(updateLiveData, requireActivity(), (next) -> {
+            if (updateLiveData.hasError()) {
+                ExceptionDialogFragment.newInstance(updateLiveData.getError(), viewModel.getCurrentAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
     }
 
     @Override
     public void deleteAccessControl(AccessControl ac) {
-        final WrappedLiveData<Void> wrappedDeleteLiveData = syncManager.deleteAccessControl(ac);
+        final WrappedLiveData<Void> wrappedDeleteLiveData = viewModel.deleteAccessControl(ac);
         adapter.remove(ac);
         observeOnce(wrappedDeleteLiveData, this, (ignored) -> {
-            if (wrappedDeleteLiveData.hasError()) {
+            if (wrappedDeleteLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(wrappedDeleteLiveData.getError())) {
                 DeckLog.logError(wrappedDeleteLiveData.getError());
                 BrandedSnackbar.make(requireView(), getString(R.string.error_revoking_ac, ac.getUser().getDisplayname()), Snackbar.LENGTH_LONG)
                         .setAction(R.string.simple_more, v -> ExceptionDialogFragment.newInstance(wrappedDeleteLiveData.getError(), viewModel.getCurrentAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName()))
@@ -129,7 +132,12 @@ public class AccessControlDialogFragment extends BrandedDialogFragment implement
         ac.setType(0L); // https://github.com/nextcloud/deck/blob/master/docs/API.md#post-boardsboardidacl---add-new-acl-rule
         ac.setUserId(user.getLocalId());
         ac.setUser(user);
-        syncManager.createAccessControl(viewModel.getCurrentAccount().getId(), ac);
+        final WrappedLiveData<AccessControl> createLiveData = viewModel.createAccessControl(viewModel.getCurrentAccount().getId(), ac);
+        observeOnce(createLiveData, this, (next) -> {
+            if (createLiveData.hasError()) {
+                ExceptionDialogFragment.newInstance(createLiveData.getError(), viewModel.getCurrentAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
         binding.people.setText("");
         userAutoCompleteAdapter.exclude(user);
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/EditLabelDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/EditLabelDialogFragment.java
index d460d1590..2dacfe6ac 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/EditLabelDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/EditLabelDialogFragment.java
@@ -58,14 +58,14 @@ public class EditLabelDialogFragment extends BrandedDialogFragment {
 
         dialogBuilder.setTitle(getString(R.string.edit_tag, label.getTitle()));
         dialogBuilder.setPositiveButton(R.string.simple_save, (dialog, which) -> {
-            this.label.setColor(binding.colorChooser.getSelectedColor().substring(1));
+            this.label.setColor(binding.colorChooser.getSelectedColor());
             this.label.setTitle(binding.input.getText().toString());
             listener.onLabelUpdated(this.label);
         });
         String title = this.label.getTitle();
         binding.input.setText(title);
         binding.input.setSelection(title.length());
-        binding.colorChooser.selectColor("#" + this.label.getColor());
+        binding.colorChooser.selectColor(this.label.getColor());
 
         return dialogBuilder
                 .setView(binding.getRoot())
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsDialogFragment.java
index 3391c7a99..bc0d98ca3 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsDialogFragment.java
@@ -38,7 +38,6 @@ public class ManageLabelsDialogFragment extends BrandedDialogFragment implements
     private static final String KEY_BOARD_ID = "board_id";
 
     private long boardId;
-    private SyncManager syncManager;
 
     @Override
     public void onAttach(@NonNull Context context) {
@@ -67,8 +66,7 @@ public class ManageLabelsDialogFragment extends BrandedDialogFragment implements
         colors = getResources().getStringArray(R.array.board_default_colors);
         adapter = new ManageLabelsAdapter(this, requireContext());
         binding.labels.setAdapter(adapter);
-        syncManager = new SyncManager(requireActivity());
-        syncManager.getFullBoardById(viewModel.getCurrentAccount().getId(), boardId).observe(this, (fullBoard) -> {
+        viewModel.getFullBoardById(viewModel.getCurrentAccount().getId(), boardId).observe(this, (fullBoard) -> {
             if (fullBoard == null) {
                 throw new IllegalStateException("FullBoard should not be null");
             }
@@ -80,9 +78,9 @@ public class ManageLabelsDialogFragment extends BrandedDialogFragment implements
             final Label label = new Label();
             label.setBoardId(boardId);
             label.setTitle(binding.addLabelTitle.getText().toString());
-            label.setColor(colors[new Random().nextInt(colors.length)].substring(1));
+            label.setColor(colors[new Random().nextInt(colors.length)]);
 
-            WrappedLiveData<Label> createLiveData = syncManager.createLabel(viewModel.getCurrentAccount().getId(), label, boardId);
+            WrappedLiveData<Label> createLiveData = viewModel.createLabel(viewModel.getCurrentAccount().getId(), label, boardId);
             observeOnce(createLiveData, this, (createdLabel) -> {
                 if (createLiveData.hasError()) {
                     final Throwable error = createLiveData.getError();
@@ -126,7 +124,7 @@ public class ManageLabelsDialogFragment extends BrandedDialogFragment implements
 
     @Override
     public void requestDelete(@NonNull Label label) {
-        observeOnce(syncManager.countCardsWithLabel(label.getLocalId()), this, (count) -> {
+        observeOnce(viewModel.countCardsWithLabel(label.getLocalId()), this, (count) -> {
             if (count > 0) {
                 new BrandedDeleteAlertDialogBuilder(requireContext())
                         .setTitle(getString(R.string.delete_something, label.getTitle()))
@@ -141,9 +139,9 @@ public class ManageLabelsDialogFragment extends BrandedDialogFragment implements
     }
 
     private void deleteLabel(@NonNull Label label) {
-        final WrappedLiveData<Void> deleteLiveData = syncManager.deleteLabel(label);
+        final WrappedLiveData<Void> deleteLiveData = viewModel.deleteLabel(label);
         observeOnce(deleteLiveData, this, (v) -> {
-            if (deleteLiveData.hasError()) {
+            if (deleteLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteLiveData.getError())) {
                 final Throwable error = deleteLiveData.getError();
                 assert error != null;
                 Toast.makeText(requireContext(), error.getLocalizedMessage(), Toast.LENGTH_LONG).show();
@@ -159,7 +157,7 @@ public class ManageLabelsDialogFragment extends BrandedDialogFragment implements
 
     @Override
     public void onLabelUpdated(@NonNull Label label) {
-        WrappedLiveData<Label> updateLiveData = syncManager.updateLabel(label);
+        WrappedLiveData<Label> updateLiveData = viewModel.updateLabel(label);
         observeOnce(updateLiveData, this, (updatedLabel) -> {
             if (updateLiveData.hasError()) {
                 final Throwable error = updateLiveData.getError();
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsViewHolder.java
index 7fa3abd89..381a290e6 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsViewHolder.java
@@ -1,14 +1,13 @@
 package it.niedermann.nextcloud.deck.ui.board.managelabels;
 
 import android.content.res.ColorStateList;
-import android.graphics.Color;
 
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.databinding.ItemManageLabelBinding;
 import it.niedermann.nextcloud.deck.model.Label;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
 
 public class ManageLabelsViewHolder extends RecyclerView.ViewHolder {
     private ItemManageLabelBinding binding;
@@ -17,13 +16,14 @@ public class ManageLabelsViewHolder extends RecyclerView.ViewHolder {
     public ManageLabelsViewHolder(ItemManageLabelBinding binding) {
         super(binding.getRoot());
         this.binding = binding;
+        this.binding.label.setClickable(false);
     }
 
     public void bind(@NonNull Label label, @NonNull ManageLabelListener listener) {
         binding.label.setText(label.getTitle());
-        final int labelColor = Color.parseColor("#" + label.getColor());
+        final int labelColor = label.getColor();
         binding.label.setChipBackgroundColor(ColorStateList.valueOf(labelColor));
-        final int color = ColorUtil.getForegroundColorForBackgroundColor(labelColor);
+        final int color = ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(labelColor);
         binding.label.setTextColor(color);
         binding.delete.setOnClickListener((v) -> listener.requestDelete(label));
         binding.editText.setOnClickListener((v) -> listener.requestEdit(label));
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedAlertDialogBuilder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedAlertDialogBuilder.java
index cfeffe7dc..880e21073 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedAlertDialogBuilder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedAlertDialogBuilder.java
@@ -9,8 +9,6 @@ import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AlertDialog;
 
-import org.jetbrains.annotations.NotNull;
-
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMainColor;
 
@@ -22,7 +20,7 @@ public class BrandedAlertDialogBuilder extends AlertDialog.Builder implements Br
         super(context);
     }
 
-    @NotNull
+    @NonNull
     @Override
     public AlertDialog create() {
         this.dialog = super.create();
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDatePickerDialog.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDatePickerDialog.java
index 5bef66f2c..319df7f79 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDatePickerDialog.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDatePickerDialog.java
@@ -17,7 +17,7 @@ import com.wdullaer.materialdatetimepicker.date.DatePickerDialog;
 import java.util.Calendar;
 
 import it.niedermann.nextcloud.deck.R;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
+import it.niedermann.nextcloud.deck.util.DeckColorUtil;
 
 import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
@@ -44,7 +44,7 @@ public class BrandedDatePickerDialog extends DatePickerDialog implements Branded
         setOkColor(buttonTextColor);
         setCancelColor(buttonTextColor);
         // Text in picker title is always white
-        setAccentColor(ColorUtil.contrastRatioIsSufficientBigAreas(Color.WHITE, mainColor) ? mainColor : ContextCompat.getColor(requireContext(), R.color.accent));
+        setAccentColor(DeckColorUtil.contrastRatioIsSufficientBigAreas(Color.WHITE, mainColor) ? mainColor : ContextCompat.getColor(requireContext(), R.color.accent));
     }
 
     /**
@@ -52,13 +52,13 @@ public class BrandedDatePickerDialog extends DatePickerDialog implements Branded
      *
      * @param callBack    How the parent is notified that the date is set.
      * @param year        The initial year of the dialog.
-     * @param monthOfYear The initial month of the dialog.
+     * @param monthOfYear The initial month of the dialog. [0 - 11]
      * @param dayOfMonth  The initial day of the dialog.
      * @return a new DatePickerDialog instance.
      */
     public static DatePickerDialog newInstance(OnDateSetListener callBack, int year, int monthOfYear, int dayOfMonth) {
         DatePickerDialog ret = new BrandedDatePickerDialog();
-        ret.initialize(callBack, year, monthOfYear, dayOfMonth);
+        ret.initialize(callBack, year, monthOfYear - 1, dayOfMonth);
         return ret;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDeleteAlertDialogBuilder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDeleteAlertDialogBuilder.java
index ec3cef553..d88fdd6cc 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDeleteAlertDialogBuilder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDeleteAlertDialogBuilder.java
@@ -5,6 +5,7 @@ import android.content.DialogInterface;
 import android.widget.Button;
 
 import androidx.annotation.CallSuper;
+import androidx.core.content.ContextCompat;
 
 import it.niedermann.nextcloud.deck.R;
 
@@ -20,7 +21,7 @@ public class BrandedDeleteAlertDialogBuilder extends BrandedAlertDialogBuilder {
         super.applyBrand(mainColor);
         final Button positiveButton = dialog.getButton(DialogInterface.BUTTON_POSITIVE);
         if (positiveButton != null) {
-            positiveButton.setTextColor(getContext().getResources().getColor(R.color.danger));
+            positiveButton.setTextColor(ContextCompat.getColor(getContext(), R.color.danger));
         }
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedSnackbar.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedSnackbar.java
index 20e6f8dc8..0159a59dc 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedSnackbar.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedSnackbar.java
@@ -11,8 +11,8 @@ import androidx.core.content.ContextCompat;
 import com.google.android.material.snackbar.BaseTransientBottomBar;
 import com.google.android.material.snackbar.Snackbar;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.R;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
 
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMainColor;
@@ -25,9 +25,9 @@ public class BrandedSnackbar {
         final Snackbar snackbar = Snackbar.make(view, text, duration);
         if (isBrandingEnabled(view.getContext())) {
             @ColorInt final int color = readBrandMainColor(view.getContext());
-            snackbar.setActionTextColor(ColorUtil.isColorDark(color) ? Color.WHITE : color);
+            snackbar.setActionTextColor(ColorUtil.INSTANCE.isColorDark(color) ? Color.WHITE : color);
         } else {
-            snackbar.setActionTextColor(ContextCompat.getColor(view.getContext(), R.color.primary));
+            snackbar.setActionTextColor(ContextCompat.getColor(view.getContext(), R.color.defaultBrand));
         }
         return snackbar;
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedTimePickerDialog.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedTimePickerDialog.java
index a1963aa18..2e0c4d3b8 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedTimePickerDialog.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedTimePickerDialog.java
@@ -14,10 +14,10 @@ import androidx.core.content.ContextCompat;
 
 import com.wdullaer.materialdatetimepicker.time.TimePickerDialog;
 
-import java.util.Calendar;
+import java.time.LocalTime;
 
 import it.niedermann.nextcloud.deck.R;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
+import it.niedermann.nextcloud.deck.util.DeckColorUtil;
 
 import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
@@ -44,7 +44,7 @@ public class BrandedTimePickerDialog extends TimePickerDialog implements Branded
         setOkColor(buttonTextColor);
         setCancelColor(buttonTextColor);
         // Text in picker title is always white
-        setAccentColor(ColorUtil.contrastRatioIsSufficientBigAreas(Color.WHITE, mainColor) ? mainColor : ContextCompat.getColor(requireContext(), R.color.accent));
+        setAccentColor(DeckColorUtil.contrastRatioIsSufficientBigAreas(Color.WHITE, mainColor) ? mainColor : ContextCompat.getColor(requireContext(), R.color.accent));
     }
 
     /**
@@ -86,9 +86,9 @@ public class BrandedTimePickerDialog extends TimePickerDialog implements Branded
      * @param is24HourMode True to render 24 hour mode, false to render AM / PM selectors.
      * @return a new TimePickerDialog instance.
      */
-    @SuppressWarnings({"unused", "SameParameterValue"})
+    @SuppressWarnings({"SameParameterValue"})
     public static TimePickerDialog newInstance(OnTimeSetListener callback, boolean is24HourMode) {
-        Calendar now = Calendar.getInstance();
-        return newInstance(callback, now.get(Calendar.HOUR_OF_DAY), now.get(Calendar.MINUTE), is24HourMode);
+        LocalTime now = LocalTime.now();
+        return newInstance(callback, now.getHour(), now.getMinute(), is24HourMode);
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandingUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandingUtil.java
index 02ad6b309..b780efec5 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandingUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandingUtil.java
@@ -17,14 +17,13 @@ import androidx.preference.PreferenceManager;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 import com.google.android.material.tabs.TabLayout;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 
 import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
-import static it.niedermann.nextcloud.deck.util.ColorUtil.contrastRatioIsSufficient;
-import static it.niedermann.nextcloud.deck.util.ColorUtil.contrastRatioIsSufficientBigAreas;
-import static it.niedermann.nextcloud.deck.util.ColorUtil.getContrastRatio;
-import static it.niedermann.nextcloud.deck.util.ColorUtil.getForegroundColorForBackgroundColor;
+import static it.niedermann.nextcloud.deck.util.DeckColorUtil.contrastRatioIsSufficient;
+import static it.niedermann.nextcloud.deck.util.DeckColorUtil.contrastRatioIsSufficientBigAreas;
 
 public abstract class BrandingUtil {
 
@@ -44,7 +43,7 @@ public abstract class BrandingUtil {
             DeckLog.log("--- Read: shared_preference_theme_main");
             return sharedPreferences.getInt(context.getString(R.string.shared_preference_theme_main), context.getApplicationContext().getResources().getColor(R.color.defaultBrand));
         } else {
-            return context.getResources().getColor(R.color.defaultBrand);
+            return ContextCompat.getColor(context, R.color.defaultBrand);
         }
     }
 
@@ -87,13 +86,13 @@ public abstract class BrandingUtil {
         fab.setSupportBackgroundTintList(ColorStateList.valueOf(contrastRatioIsSufficient
                 ? mainColor
                 : ContextCompat.getColor(fab.getContext(), R.color.accent)));
-        fab.setColorFilter(contrastRatioIsSufficient ? getForegroundColorForBackgroundColor(mainColor) : mainColor);
+        fab.setColorFilter(contrastRatioIsSufficient ? ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(mainColor) : mainColor);
     }
 
     public static void applyBrandToPrimaryTabLayout(@ColorInt int mainColor, @NonNull TabLayout tabLayout) {
-        @ColorInt int finalMainColor = getSecondaryForegroundColorDependingOnTheme(tabLayout.getContext(), mainColor);
+        @ColorInt final int finalMainColor = getSecondaryForegroundColorDependingOnTheme(tabLayout.getContext(), mainColor);
         tabLayout.setBackgroundColor(ContextCompat.getColor(tabLayout.getContext(), R.color.primary));
-        final boolean contrastRatioIsSufficient = getContrastRatio(mainColor, ContextCompat.getColor(tabLayout.getContext(), R.color.primary)) > 1.7d;
+        final boolean contrastRatioIsSufficient = ColorUtil.INSTANCE.getContrastRatio(mainColor, ContextCompat.getColor(tabLayout.getContext(), R.color.primary)) > 1.7d;
         tabLayout.setSelectedTabIndicatorColor(contrastRatioIsSufficient ? mainColor : finalMainColor);
     }
 
@@ -112,7 +111,7 @@ public abstract class BrandingUtil {
                         finalMainColor,
                         finalMainColor,
                         finalMainColor,
-                        editText.getContext().getResources().getColor(R.color.fg_secondary)
+                        ContextCompat.getColor(editText.getContext(), R.color.fg_secondary)
                 }
         ));
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AbstractCardViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AbstractCardViewHolder.java
new file mode 100644
index 000000000..4d3b8bb35
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/AbstractCardViewHolder.java
@@ -0,0 +1,122 @@
+package it.niedermann.nextcloud.deck.ui.card;
+
+import android.content.Context;
+import android.view.Menu;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.view.View.OnLongClickListener;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import androidx.annotation.CallSuper;
+import androidx.annotation.ColorInt;
+import androidx.annotation.MenuRes;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.appcompat.widget.PopupMenu;
+import androidx.core.graphics.drawable.DrawableCompat;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.google.android.material.card.MaterialCardView;
+
+import org.jetbrains.annotations.Contract;
+
+import java.time.ZoneId;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.model.enums.DBStatus;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.util.DateUtil;
+import it.niedermann.nextcloud.deck.util.ViewUtil;
+
+public abstract class AbstractCardViewHolder extends RecyclerView.ViewHolder {
+
+    public AbstractCardViewHolder(@NonNull View itemView) {
+        super(itemView);
+    }
+
+    /**
+     * Removes all {@link OnClickListener} and {@link OnLongClickListener}
+     */
+    @CallSuper
+    public void bind(@NonNull FullCard fullCard, @NonNull Account account, @Nullable Long boardRemoteId, boolean hasEditPermission, @MenuRes int optionsMenu, @NonNull CardOptionsItemSelectedListener optionsItemsSelectedListener, @NonNull String counterMaxValue, @ColorInt int mainColor) {
+        final Context context = itemView.getContext();
+
+        bindCardClickListener(null);
+        bindCardLongClickListener(null);
+
+        getCardMenu().setVisibility(hasEditPermission ? View.VISIBLE : View.GONE);
+        getCardTitle().setText(fullCard.getCard().getTitle().trim());
+
+        DrawableCompat.setTint(getNotSyncedYet().getDrawable(), mainColor);
+        getNotSyncedYet().setVisibility(DBStatus.LOCAL_EDITED.equals(fullCard.getStatusEnum()) ? View.VISIBLE : View.GONE);
+
+        if (fullCard.getCard().getDueDate() != null) {
+            setupDueDate(getCardDueDate(), fullCard.getCard());
+            getCardDueDate().setVisibility(View.VISIBLE);
+        } else {
+            getCardDueDate().setVisibility(View.GONE);
+        }
+
+        getCardMenu().setOnClickListener(view -> {
+            final PopupMenu popup = new PopupMenu(context, view);
+            popup.inflate(optionsMenu);
+            final Menu menu = popup.getMenu();
+            if (containsUser(fullCard.getAssignedUsers(), account.getUserName())) {
+                menu.removeItem(menu.findItem(R.id.action_card_assign).getItemId());
+            } else {
+                menu.removeItem(menu.findItem(R.id.action_card_unassign).getItemId());
+            }
+            if (boardRemoteId == null || fullCard.getCard().getId() == null) {
+                menu.removeItem(R.id.share_link);
+            }
+
+            popup.setOnMenuItemClickListener(item -> optionsItemsSelectedListener.onCardOptionsItemSelected(item, fullCard));
+            popup.show();
+        });
+    }
+
+    protected abstract TextView getCardDueDate();
+
+    protected abstract ImageView getNotSyncedYet();
+
+    protected abstract TextView getCardTitle();
+
+    protected abstract View getCardMenu();
+
+    protected abstract MaterialCardView getCard();
+
+    public void bindCardClickListener(@Nullable OnClickListener l) {
+        getCard().setOnClickListener(l);
+    }
+
+    public void bindCardLongClickListener(@Nullable OnLongClickListener l) {
+        getCard().setOnLongClickListener(l);
+    }
+
+    public MaterialCardView getDraggable() {
+        return getCard();
+    }
+
+    private static void setupDueDate(@NonNull TextView cardDueDate, @NonNull Card card) {
+        final Context context = cardDueDate.getContext();
+        cardDueDate.setText(DateUtil.getRelativeDateTimeString(context, card.getDueDate().toEpochMilli()));
+        ViewUtil.themeDueDate(context, cardDueDate, card.getDueDate().atZone(ZoneId.systemDefault()).toLocalDate());
+    }
+
+    @Contract("null, _ -> false")
+    private static boolean containsUser(List<User> userList, String username) {
+        if (userList != null) {
+            for (User user : userList) {
+                if (user.getPrimaryKey().equals(username)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardAdapter.java
index 986a66cad..87140e544 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardAdapter.java
@@ -1,99 +1,82 @@
 package it.niedermann.nextcloud.deck.ui.card;
 
-import android.annotation.SuppressLint;
 import android.content.ClipData;
 import android.content.Context;
 import android.content.Intent;
 import android.view.LayoutInflater;
-import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.PopupMenu;
-import android.widget.TextView;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
-import androidx.core.graphics.drawable.DrawableCompat;
+import androidx.core.content.ContextCompat;
 import androidx.fragment.app.FragmentManager;
 import androidx.lifecycle.LifecycleOwner;
 import androidx.recyclerview.widget.RecyclerView;
 
-import org.jetbrains.annotations.Contract;
-import org.jetbrains.annotations.NotNull;
-
 import java.util.ArrayList;
-import java.util.LinkedList;
 import java.util.List;
 
 import it.niedermann.android.crosstabdnd.DragAndDropAdapter;
 import it.niedermann.android.crosstabdnd.DraggedItemLocalState;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
-import it.niedermann.nextcloud.deck.databinding.ItemCardBinding;
+import it.niedermann.nextcloud.deck.databinding.ItemCardCompactBinding;
+import it.niedermann.nextcloud.deck.databinding.ItemCardDefaultBinding;
+import it.niedermann.nextcloud.deck.databinding.ItemCardDefaultOnlyTitleBinding;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Card;
-import it.niedermann.nextcloud.deck.model.Label;
 import it.niedermann.nextcloud.deck.model.Stack;
-import it.niedermann.nextcloud.deck.model.User;
-import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
-import it.niedermann.nextcloud.deck.model.full.FullStack;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
-import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
+import it.niedermann.nextcloud.deck.ui.MainViewModel;
 import it.niedermann.nextcloud.deck.ui.branding.Branded;
-import it.niedermann.nextcloud.deck.ui.branding.BrandedAlertDialogBuilder;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
-import it.niedermann.nextcloud.deck.util.DateUtil;
-import it.niedermann.nextcloud.deck.util.ViewUtil;
+import it.niedermann.nextcloud.deck.ui.movecard.MoveCardDialogFragment;
 
+import static androidx.preference.PreferenceManager.getDefaultSharedPreferences;
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
 import static it.niedermann.nextcloud.deck.util.MimeTypeUtil.TEXT_PLAIN;
 
-public class CardAdapter extends RecyclerView.Adapter<ItemCardViewHolder> implements DragAndDropAdapter<FullCard>, Branded {
-
-    protected final SyncManager syncManager;
+public class CardAdapter extends RecyclerView.Adapter<AbstractCardViewHolder> implements DragAndDropAdapter<FullCard>, CardOptionsItemSelectedListener, Branded {
 
-    private final FragmentManager fragmentManager;
-    private final Account account;
-    @Nullable
-    private final Long currentBoardRemoteId;
-    private final long boardId;
+    private final boolean compactMode;
+    @NonNull
+    protected final MainViewModel mainViewModel;
+    @NonNull
+    protected final FragmentManager fragmentManager;
     private final long stackId;
-    private final boolean canEdit;
     @NonNull
     private final Context context;
     @Nullable
     private final SelectCardListener selectCardListener;
-    private List<FullCard> cardList = new LinkedList<>();
-    private LifecycleOwner lifecycleOwner;
-    private List<FullStack> availableStacks = new ArrayList<>();
-    private String counterMaxValue;
-
-    private int mainColor;
+    @NonNull
+    protected List<FullCard> cardList = new ArrayList<>();
+    @NonNull
+    protected LifecycleOwner lifecycleOwner;
+    @NonNull
+    protected String counterMaxValue;
+    @ColorInt
+    protected int mainColor;
     @StringRes
-    private int shareLinkRes;
+    private final int shareLinkRes;
 
-    public CardAdapter(@NonNull Context context, @NonNull FragmentManager fragmentManager, @NonNull Account account, long boardId, @Nullable Long currentBoardRemoteId, long stackId, boolean canEdit, @NonNull SyncManager syncManager, @NonNull LifecycleOwner lifecycleOwner, @Nullable SelectCardListener selectCardListener) {
+    public CardAdapter(@NonNull Context context, @NonNull FragmentManager fragmentManager, long stackId, @NonNull MainViewModel mainViewModel, @NonNull LifecycleOwner lifecycleOwner, @Nullable SelectCardListener selectCardListener) {
         this.context = context;
+        this.counterMaxValue = context.getString(R.string.counter_max_value);
         this.fragmentManager = fragmentManager;
         this.lifecycleOwner = lifecycleOwner;
-        this.account = account;
-        this.shareLinkRes = account.getServerDeckVersionAsObject().getShareLinkResource();
-        this.boardId = boardId;
-        this.currentBoardRemoteId = currentBoardRemoteId;
+        this.shareLinkRes = mainViewModel.getCurrentAccount().getServerDeckVersionAsObject().getShareLinkResource();
         this.stackId = stackId;
-        this.canEdit = canEdit;
-        this.syncManager = syncManager;
+        this.mainViewModel = mainViewModel;
         this.selectCardListener = selectCardListener;
-        this.mainColor = context.getResources().getColor(R.color.primary);
-        syncManager.getStacksForBoard(account.getId(), boardId).observe(this.lifecycleOwner, (stacks) -> {
-            availableStacks.clear();
-            availableStacks.addAll(stacks);
-        });
+        this.mainColor = ContextCompat.getColor(context, R.color.defaultBrand);
+        this.compactMode = getDefaultSharedPreferences(context).getBoolean(context.getString(R.string.pref_key_compact), false);
         setHasStableIds(true);
     }
 
@@ -104,118 +87,62 @@ public class CardAdapter extends RecyclerView.Adapter<ItemCardViewHolder> implem
 
     @NonNull
     @Override
-    public ItemCardViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int position) {
-        final Context context = viewGroup.getContext();
-        counterMaxValue = context.getString(R.string.counter_max_value);
+    public AbstractCardViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
+        if (viewType == R.layout.item_card_compact) {
+            return new CompactCardViewHolder(ItemCardCompactBinding.inflate(LayoutInflater.from(viewGroup.getContext()), viewGroup, false));
+        } else if (viewType == R.layout.item_card_default_only_title) {
+            return new DefaultCardOnlyTitleViewHolder(ItemCardDefaultOnlyTitleBinding.inflate(LayoutInflater.from(viewGroup.getContext()), viewGroup, false));
+        }
+        return new DefaultCardViewHolder(ItemCardDefaultBinding.inflate(LayoutInflater.from(viewGroup.getContext()), viewGroup, false));
+    }
 
-        LayoutInflater layoutInflater = LayoutInflater.from(context);
-        ItemCardBinding binding = ItemCardBinding.inflate(layoutInflater, viewGroup, false);
-        return new ItemCardViewHolder(binding);
+    @Override
+    public int getItemViewType(int position) {
+        if (compactMode) {
+            return R.layout.item_card_compact;
+        } else {
+            final FullCard fullCard = cardList.get(position);
+            if (fullCard.getAttachments().size() == 0
+                    && fullCard.getAssignedUsers().size() == 0
+                    && fullCard.getLabels().size() == 0
+                    && fullCard.getCommentCount() == 0) {
+                return R.layout.item_card_default_only_title;
+            }
+            return R.layout.item_card_default;
+        }
     }
 
-    @SuppressLint("SetTextI18n")
     @Override
-    public void onBindViewHolder(@NonNull ItemCardViewHolder viewHolder, int position) {
-        final Context context = viewHolder.itemView.getContext();
-        final FullCard card = cardList.get(position);
+    public void onBindViewHolder(@NonNull AbstractCardViewHolder viewHolder, int position) {
+        @NonNull FullCard fullCard = cardList.get(position);
+        viewHolder.bind(fullCard, mainViewModel.getCurrentAccount(), mainViewModel.getCurrentBoardRemoteId(), mainViewModel.currentBoardHasEditPermission(), R.menu.card_menu, this, counterMaxValue, mainColor);
 
-        viewHolder.binding.card.setOnClickListener((v) -> {
+        // Only enable details view if there is no one waiting for selecting a card.
+        viewHolder.bindCardClickListener((v) -> {
             if (selectCardListener == null) {
-                context.startActivity(EditActivity.createEditCardIntent(context, account, boardId, card.getLocalId()));
+                context.startActivity(EditActivity.createEditCardIntent(context, mainViewModel.getCurrentAccount(), mainViewModel.getCurrentBoardLocalId(), fullCard.getLocalId()));
             } else {
-                selectCardListener.onCardSelected(card);
+                selectCardListener.onCardSelected(fullCard);
             }
         });
-        if (canEdit && selectCardListener == null) {
-            viewHolder.binding.card.setOnLongClickListener((v) -> {
+
+        // Only enable Drag and Drop if there is no one waiting for selecting a card.
+        if (selectCardListener == null) {
+            viewHolder.bindCardLongClickListener((v) -> {
                 DeckLog.log("Starting drag and drop");
-                v.startDrag(ClipData.newPlainText("cardid", String.valueOf(card.getLocalId())),
+                v.startDrag(ClipData.newPlainText("cardid", String.valueOf(fullCard.getLocalId())),
                         new View.DragShadowBuilder(v),
-                        new DraggedItemLocalState<>(card, viewHolder.binding.card, this, position),
+                        new DraggedItemLocalState<>(fullCard, viewHolder.getDraggable(), this, position),
                         0
                 );
                 return true;
             });
-        } else {
-            viewHolder.binding.cardMenu.setVisibility(View.GONE);
-        }
-        viewHolder.binding.cardTitle.setText(card.getCard().getTitle().trim());
-
-        if (card.getAssignedUsers() != null && card.getAssignedUsers().size() > 0) {
-            viewHolder.binding.overlappingAvatars.setAvatars(account, card.getAssignedUsers());
-            viewHolder.binding.overlappingAvatars.setVisibility(View.VISIBLE);
-        } else {
-            viewHolder.binding.overlappingAvatars.setVisibility(View.GONE);
         }
-
-        DrawableCompat.setTint(viewHolder.binding.notSyncedYet.getDrawable(), mainColor);
-        viewHolder.binding.notSyncedYet.setVisibility(DBStatus.LOCAL_EDITED.equals(card.getStatusEnum()) ? View.VISIBLE : View.GONE);
-
-        if (card.getCard().getDueDate() != null) {
-            setupDueDate(viewHolder.binding.cardDueDate, card.getCard());
-            viewHolder.binding.cardDueDate.setVisibility(View.VISIBLE);
-        } else {
-            viewHolder.binding.cardDueDate.setVisibility(View.GONE);
-        }
-
-        final int attachmentsCount = card.getAttachments().size();
-
-        if (attachmentsCount == 0) {
-            viewHolder.binding.cardCountAttachments.setVisibility(View.GONE);
-        } else {
-            setupCounter(viewHolder.binding.cardCountAttachments, attachmentsCount);
-            viewHolder.binding.cardCountAttachments.setVisibility(View.VISIBLE);
-        }
-
-        final int commentsCount = card.getCommentCount();
-
-        if (commentsCount == 0) {
-            viewHolder.binding.cardCountComments.setVisibility(View.GONE);
-        } else {
-            setupCounter(viewHolder.binding.cardCountComments, commentsCount);
-
-            viewHolder.binding.cardCountComments.setVisibility(View.VISIBLE);
-        }
-
-        List<Label> labels = card.getLabels();
-        if (labels != null && labels.size() > 0) {
-            viewHolder.binding.labels.updateLabels(labels);
-            viewHolder.binding.labels.setVisibility(View.VISIBLE);
-        } else {
-            viewHolder.binding.labels.removeAllViews();
-            viewHolder.binding.labels.setVisibility(View.GONE);
-        }
-
-        Card.TaskStatus taskStatus = card.getCard().getTaskStatus();
-        if (taskStatus.taskCount > 0) {
-            viewHolder.binding.cardCountTasks.setText(context.getResources().getString(R.string.task_count, String.valueOf(taskStatus.doneCount), String.valueOf(taskStatus.taskCount)));
-            viewHolder.binding.cardCountTasks.setVisibility(View.VISIBLE);
-        } else {
-            viewHolder.binding.cardCountTasks.setVisibility(View.GONE);
-        }
-
-        viewHolder.binding.cardMenu.setOnClickListener(v -> onOverflowIconClicked(v, card));
-    }
-
-    private void setupCounter(@NonNull TextView textView, int count) {
-        if (count > 99) {
-            textView.setText(counterMaxValue);
-        } else if (count > 1) {
-            textView.setText(String.valueOf(count));
-        } else if (count == 1) {
-            textView.setText("");
-        }
-    }
-
-    private void setupDueDate(@NonNull TextView cardDueDate, @NotNull Card card) {
-        final Context context = cardDueDate.getContext();
-        cardDueDate.setText(DateUtil.getRelativeDateTimeString(context, card.getDueDate().getTime()));
-        ViewUtil.themeDueDate(context, cardDueDate, card.getDueDate());
     }
 
     @Override
     public int getItemCount() {
-        return cardList == null ? 0 : cardList.size();
+        return cardList.size();
     }
 
     public void insertItem(FullCard fullCard, int position) {
@@ -223,6 +150,7 @@ public class CardAdapter extends RecyclerView.Adapter<ItemCardViewHolder> implem
         notifyItemInserted(position);
     }
 
+    @NonNull
     @Override
     public List<FullCard> getItemList() {
         return this.cardList;
@@ -240,114 +168,59 @@ public class CardAdapter extends RecyclerView.Adapter<ItemCardViewHolder> implem
         notifyItemRemoved(position);
     }
 
-    protected void onOverflowIconClicked(@NotNull View view, FullCard card) {
-        final Context context = view.getContext();
-        final PopupMenu popup = new PopupMenu(context, view);
-        popup.inflate(R.menu.card_menu);
-        prepareOptionsMenu(popup.getMenu(), card);
-
-        popup.setOnMenuItemClickListener(item -> optionsItemSelected(context, item, card));
-        popup.show();
-    }
-
-    protected void prepareOptionsMenu(Menu menu, @NotNull FullCard card) {
-        if (containsUser(card.getAssignedUsers(), account.getUserName())) {
-            menu.removeItem(menu.findItem(R.id.action_card_assign).getItemId());
-        } else {
-            menu.removeItem(menu.findItem(R.id.action_card_unassign).getItemId());
-        }
-        if (currentBoardRemoteId == null || card.getCard().getId() == null) {
-            menu.removeItem(R.id.share_link);
-        }
-    }
-
     public void setCardList(@NonNull List<FullCard> cardList) {
         this.cardList.clear();
         this.cardList.addAll(cardList);
         notifyDataSetChanged();
     }
 
-    @Contract("null, _ -> false")
-    private boolean containsUser(List<User> userList, String username) {
-        if (userList != null) {
-            for (User user : userList) {
-                if (user.getPrimaryKey().equals(username)) {
-                    return true;
-                }
-            }
-        }
-        return false;
+    @Override
+    public void applyBrand(int mainColor) {
+        this.mainColor = getSecondaryForegroundColorDependingOnTheme(context, mainColor);
+        notifyDataSetChanged();
     }
 
-    protected boolean optionsItemSelected(@NonNull Context context, @NotNull MenuItem item, FullCard fullCard) {
-        switch (item.getItemId()) {
-            case R.id.share_link: {
-                Intent shareIntent = new Intent()
-                        .setAction(Intent.ACTION_SEND)
-                        .setType(TEXT_PLAIN)
-                        .putExtra(Intent.EXTRA_SUBJECT, fullCard.getCard().getTitle())
-                        .putExtra(Intent.EXTRA_TITLE, fullCard.getCard().getTitle())
-                        .putExtra(Intent.EXTRA_TEXT, account.getUrl() + context.getString(shareLinkRes, currentBoardRemoteId, fullCard.getCard().getId()));
-                context.startActivity(Intent.createChooser(shareIntent, fullCard.getCard().getTitle()));
-            }
-            case R.id.action_card_assign: {
-                new Thread(() -> syncManager.assignUserToCard(syncManager.getUserByUidDirectly(fullCard.getCard().getAccountId(), account.getUserName()), fullCard.getCard())).start();
-                return true;
-            }
-            case R.id.action_card_unassign: {
-                new Thread(() -> syncManager.unassignUserFromCard(syncManager.getUserByUidDirectly(fullCard.getCard().getAccountId(), account.getUserName()), fullCard.getCard())).start();
-                return true;
-            }
-            case R.id.action_card_move: {
-                int currentStackItem = 0;
-                CharSequence[] items = new CharSequence[availableStacks.size()];
-                for (int i = 0; i < availableStacks.size(); i++) {
-                    final Stack stack = availableStacks.get(i).getStack();
-                    items[i] = stack.getTitle();
-                    if (stack.getLocalId().equals(stackId)) {
-                        currentStackItem = i;
-                    }
+    @Override
+    public boolean onCardOptionsItemSelected(@NonNull MenuItem menuItem, @NonNull FullCard fullCard) {
+        int itemId = menuItem.getItemId();
+        final Account account = mainViewModel.getCurrentAccount();
+        if (itemId == R.id.share_link) {
+            Intent shareIntent = new Intent()
+                    .setAction(Intent.ACTION_SEND)
+                    .setType(TEXT_PLAIN)
+                    .putExtra(Intent.EXTRA_SUBJECT, fullCard.getCard().getTitle())
+                    .putExtra(Intent.EXTRA_TITLE, fullCard.getCard().getTitle())
+                    .putExtra(Intent.EXTRA_TEXT, account.getUrl() + context.getString(shareLinkRes, mainViewModel.getCurrentBoardRemoteId(), fullCard.getCard().getId()));
+            context.startActivity(Intent.createChooser(shareIntent, fullCard.getCard().getTitle()));
+            new Thread(() -> mainViewModel.assignUserToCard(mainViewModel.getUserByUidDirectly(fullCard.getCard().getAccountId(), account.getUserName()), fullCard.getCard())).start();
+            return true;
+        } else if (itemId == R.id.action_card_assign) {
+            new Thread(() -> mainViewModel.assignUserToCard(mainViewModel.getUserByUidDirectly(fullCard.getCard().getAccountId(), account.getUserName()), fullCard.getCard())).start();
+            return true;
+        } else if (itemId == R.id.action_card_unassign) {
+            new Thread(() -> mainViewModel.unassignUserFromCard(mainViewModel.getUserByUidDirectly(fullCard.getCard().getAccountId(), account.getUserName()), fullCard.getCard())).start();
+            return true;
+        } else if (itemId == R.id.action_card_move) {
+            DeckLog.verbose("[Move card] Launch move dialog for " + Card.class.getSimpleName() + " \"" + fullCard.getCard().getTitle() + "\" (#" + fullCard.getLocalId() + ") from " + Stack.class.getSimpleName() + " #" + +stackId);
+            MoveCardDialogFragment.newInstance(fullCard.getAccountId(), mainViewModel.getCurrentBoardLocalId(), fullCard.getCard().getTitle(), fullCard.getLocalId()).show(fragmentManager, MoveCardDialogFragment.class.getSimpleName());
+            return true;
+        } else if (itemId == R.id.action_card_archive) {
+            final WrappedLiveData<FullCard> archiveLiveData = mainViewModel.archiveCard(fullCard);
+            observeOnce(archiveLiveData, lifecycleOwner, (v) -> {
+                if (archiveLiveData.hasError()) {
+                    ExceptionDialogFragment.newInstance(archiveLiveData.getError(), account).show(fragmentManager, ExceptionDialogFragment.class.getSimpleName());
                 }
-                final FullCard newCard = fullCard;
-                new BrandedAlertDialogBuilder(context)
-                        .setSingleChoiceItems(items, currentStackItem, (dialog, which) -> {
-                            dialog.cancel();
-                            newCard.getCard().setStackId(availableStacks.get(which).getStack().getLocalId());
-                            LiveDataHelper.observeOnce(syncManager.updateCard(newCard), lifecycleOwner, (c) -> {
-                                // Nothing to do here...
-                            });
-                            DeckLog.log("Moved card \"" + fullCard.getCard().getTitle() + "\" to \"" + availableStacks.get(which).getStack().getTitle() + "\"");
-                        })
-                        .setNeutralButton(android.R.string.cancel, null)
-                        .setTitle(context.getString(R.string.action_card_move_title, fullCard.getCard().getTitle()))
-                        .show();
-                return true;
-            }
-            case R.id.action_card_archive: {
-                final WrappedLiveData<FullCard> archiveLiveData = syncManager.archiveCard(fullCard);
-                observeOnce(archiveLiveData, lifecycleOwner, (v) -> {
-                    if (archiveLiveData.hasError()) {
-                        ExceptionDialogFragment.newInstance(archiveLiveData.getError(), account).show(fragmentManager, ExceptionDialogFragment.class.getSimpleName());
-                    }
-                });
-                return true;
-            }
-            case R.id.action_card_delete: {
-                final WrappedLiveData<Void> deleteLiveData = syncManager.deleteCard(fullCard.getCard());
-                observeOnce(deleteLiveData, lifecycleOwner, (v) -> {
-                    if (deleteLiveData.hasError()) {
-                        ExceptionDialogFragment.newInstance(deleteLiveData.getError(), account).show(fragmentManager, ExceptionDialogFragment.class.getSimpleName());
-                    }
-                });
-                return true;
-            }
+            });
+            return true;
+        } else if (itemId == R.id.action_card_delete) {
+            final WrappedLiveData<Void> deleteLiveData = mainViewModel.deleteCard(fullCard.getCard());
+            observeOnce(deleteLiveData, lifecycleOwner, (v) -> {
+                if (deleteLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteLiveData.getError())) {
+                    ExceptionDialogFragment.newInstance(deleteLiveData.getError(), account).show(fragmentManager, ExceptionDialogFragment.class.getSimpleName());
+                }
+            });
+            return true;
         }
         return true;
     }
-
-    @Override
-    public void applyBrand(int mainColor) {
-        this.mainColor = getSecondaryForegroundColorDependingOnTheme(context, mainColor);
-        notifyDataSetChanged();
-    }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardOptionsItemSelectedListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardOptionsItemSelectedListener.java
new file mode 100644
index 000000000..d3050b732
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardOptionsItemSelectedListener.java
@@ -0,0 +1,11 @@
+package it.niedermann.nextcloud.deck.ui.card;
+
+import android.view.MenuItem;
+
+import androidx.annotation.NonNull;
+
+import it.niedermann.nextcloud.deck.model.full.FullCard;
+
+public interface CardOptionsItemSelectedListener {
+    boolean onCardOptionsItemSelected(@NonNull MenuItem menuItem, @NonNull FullCard fullCard);
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CompactCardViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CompactCardViewHolder.java
new file mode 100644
index 000000000..e9f366d99
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CompactCardViewHolder.java
@@ -0,0 +1,84 @@
+package it.niedermann.nextcloud.deck.ui.card;
+
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.view.View.OnLongClickListener;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import androidx.annotation.ColorInt;
+import androidx.annotation.MenuRes;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.google.android.material.card.MaterialCardView;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.databinding.ItemCardCompactBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Label;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
+
+public class CompactCardViewHolder extends AbstractCardViewHolder {
+    private ItemCardCompactBinding binding;
+
+    @SuppressWarnings("WeakerAccess")
+    public CompactCardViewHolder(@NonNull ItemCardCompactBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    /**
+     * Removes all {@link OnClickListener} and {@link OnLongClickListener}
+     */
+    public void bind(@NonNull FullCard fullCard, @NonNull Account account, @Nullable Long boardRemoteId, boolean hasEditPermission, @MenuRes int optionsMenu, @NonNull CardOptionsItemSelectedListener optionsItemsSelectedListener, @NonNull String counterMaxValue, @ColorInt int mainColor) {
+        super.bind(fullCard, account, boardRemoteId, hasEditPermission, optionsMenu, optionsItemsSelectedListener, counterMaxValue, mainColor);
+
+        List<Label> labels = fullCard.getLabels();
+        if (labels != null && labels.size() > 0) {
+            binding.labels.updateLabels(labels);
+            binding.labels.setVisibility(View.VISIBLE);
+        } else {
+            binding.labels.removeAllViews();
+            binding.labels.setVisibility(View.GONE);
+        }
+    }
+
+    public void bindCardClickListener(@Nullable OnClickListener l) {
+        binding.card.setOnClickListener(l);
+    }
+
+    public void bindCardLongClickListener(@Nullable OnLongClickListener l) {
+        binding.card.setOnLongClickListener(l);
+    }
+
+    public MaterialCardView getDraggable() {
+        return binding.card;
+    }
+
+    @Override
+    protected TextView getCardDueDate() {
+        return binding.cardDueDate;
+    }
+
+    @Override
+    protected ImageView getNotSyncedYet() {
+        return binding.notSyncedYet;
+    }
+
+    @Override
+    protected TextView getCardTitle() {
+        return binding.cardTitle;
+    }
+
+    @Override
+    protected View getCardMenu() {
+        return binding.cardMenu;
+    }
+
+    @Override
+    protected MaterialCardView getCard() {
+        return binding.card;
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/DefaultCardOnlyTitleViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/DefaultCardOnlyTitleViewHolder.java
new file mode 100644
index 000000000..2f9e132c9
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/DefaultCardOnlyTitleViewHolder.java
@@ -0,0 +1,61 @@
+package it.niedermann.nextcloud.deck.ui.card;
+
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.view.View.OnLongClickListener;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.google.android.material.card.MaterialCardView;
+
+import it.niedermann.nextcloud.deck.databinding.ItemCardDefaultOnlyTitleBinding;
+
+public class DefaultCardOnlyTitleViewHolder extends AbstractCardViewHolder {
+    private ItemCardDefaultOnlyTitleBinding binding;
+
+    @SuppressWarnings("WeakerAccess")
+    public DefaultCardOnlyTitleViewHolder(@NonNull ItemCardDefaultOnlyTitleBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bindCardClickListener(@Nullable OnClickListener l) {
+        binding.card.setOnClickListener(l);
+    }
+
+    public void bindCardLongClickListener(@Nullable OnLongClickListener l) {
+        binding.card.setOnLongClickListener(l);
+    }
+
+    public MaterialCardView getDraggable() {
+        return binding.card;
+    }
+
+    @Override
+    protected TextView getCardDueDate() {
+        return binding.cardDueDate;
+    }
+
+    @Override
+    protected ImageView getNotSyncedYet() {
+        return binding.notSyncedYet;
+    }
+
+    @Override
+    protected TextView getCardTitle() {
+        return binding.cardTitle;
+    }
+
+    @Override
+    protected View getCardMenu() {
+        return binding.cardMenu;
+    }
+
+    @Override
+    protected MaterialCardView getCard() {
+        return binding.card;
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/DefaultCardViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/DefaultCardViewHolder.java
new file mode 100644
index 000000000..6025cdada
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/DefaultCardViewHolder.java
@@ -0,0 +1,157 @@
+package it.niedermann.nextcloud.deck.ui.card;
+
+import android.content.Context;
+import android.text.TextUtils;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.view.View.OnLongClickListener;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import androidx.annotation.ColorInt;
+import androidx.annotation.MenuRes;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
+
+import com.google.android.material.card.MaterialCardView;
+
+import org.jetbrains.annotations.Contract;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ItemCardDefaultBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Card.TaskStatus;
+import it.niedermann.nextcloud.deck.model.Label;
+import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
+
+public class DefaultCardViewHolder extends AbstractCardViewHolder {
+    private ItemCardDefaultBinding binding;
+
+    @SuppressWarnings("WeakerAccess")
+    public DefaultCardViewHolder(@NonNull ItemCardDefaultBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    /**
+     * Removes all {@link OnClickListener} and {@link OnLongClickListener}
+     */
+    public void bind(@NonNull FullCard fullCard, @NonNull Account account, @Nullable Long boardRemoteId, boolean hasEditPermission, @MenuRes int optionsMenu, @NonNull CardOptionsItemSelectedListener optionsItemsSelectedListener, @NonNull String counterMaxValue, @ColorInt int mainColor) {
+        super.bind(fullCard, account, boardRemoteId, hasEditPermission, optionsMenu, optionsItemsSelectedListener, counterMaxValue, mainColor);
+
+        final Context context = itemView.getContext();
+
+        if (fullCard.getAssignedUsers() != null && fullCard.getAssignedUsers().size() > 0) {
+            binding.overlappingAvatars.setAvatars(account, fullCard.getAssignedUsers());
+            binding.overlappingAvatars.setVisibility(View.VISIBLE);
+        } else {
+            binding.overlappingAvatars.setVisibility(View.GONE);
+        }
+
+        final int attachmentsCount = fullCard.getAttachments().size();
+        if (attachmentsCount == 0) {
+            binding.cardCountAttachments.setVisibility(View.GONE);
+        } else {
+            setupCounter(binding.cardCountAttachments, counterMaxValue, attachmentsCount);
+            binding.cardCountAttachments.setVisibility(View.VISIBLE);
+        }
+
+        final int commentsCount = fullCard.getCommentCount();
+        if (commentsCount == 0) {
+            binding.cardCountComments.setVisibility(View.GONE);
+        } else {
+            setupCounter(binding.cardCountComments, counterMaxValue, commentsCount);
+
+            binding.cardCountComments.setVisibility(View.VISIBLE);
+        }
+
+        final List<Label> labels = fullCard.getLabels();
+        if (labels != null && labels.size() > 0) {
+            binding.labels.updateLabels(labels);
+            binding.labels.setVisibility(View.VISIBLE);
+        } else {
+            binding.labels.removeAllViews();
+            binding.labels.setVisibility(View.GONE);
+        }
+
+        final TaskStatus taskStatus = fullCard.getCard().getTaskStatus();
+        if (taskStatus.taskCount > 0) {
+            binding.cardCountTasks.setText(context.getResources().getString(R.string.task_count, String.valueOf(taskStatus.doneCount), String.valueOf(taskStatus.taskCount)));
+            binding.cardCountTasks.setCompoundDrawablesWithIntrinsicBounds(ContextCompat.getDrawable(context, R.drawable.ic_check_grey600_24dp), null, null, null);
+            binding.cardCountTasks.setVisibility(View.VISIBLE);
+        } else {
+            final String description = fullCard.getCard().getDescription();
+            if (!TextUtils.isEmpty(description)) {
+                binding.cardCountTasks.setCompoundDrawablesWithIntrinsicBounds(ContextCompat.getDrawable(context, R.drawable.ic_baseline_subject_24), null, null, null);
+                binding.cardCountTasks.setText(null);
+                binding.cardCountTasks.setVisibility(View.VISIBLE);
+            } else {
+                binding.cardCountTasks.setVisibility(View.GONE);
+            }
+        }
+    }
+
+    @Override
+    protected TextView getCardDueDate() {
+        return binding.cardDueDate;
+    }
+
+    @Override
+    protected ImageView getNotSyncedYet() {
+        return binding.notSyncedYet;
+    }
+
+    @Override
+    protected TextView getCardTitle() {
+        return binding.cardTitle;
+    }
+
+    @Override
+    protected View getCardMenu() {
+        return binding.cardMenu;
+    }
+
+    @Override
+    protected MaterialCardView getCard() {
+        return binding.card;
+    }
+
+    public void bindCardClickListener(@Nullable OnClickListener l) {
+        binding.card.setOnClickListener(l);
+    }
+
+    public void bindCardLongClickListener(@Nullable OnLongClickListener l) {
+        binding.card.setOnLongClickListener(l);
+    }
+
+    public MaterialCardView getDraggable() {
+        return binding.card;
+    }
+
+
+    private static void setupCounter(@NonNull TextView textView, @NonNull String counterMaxValue, int count) {
+        if (count > 99) {
+            textView.setText(counterMaxValue);
+        } else if (count > 1) {
+            textView.setText(String.valueOf(count));
+        } else if (count == 1) {
+            textView.setText("");
+        }
+    }
+
+    @Contract("null, _ -> false")
+    private static boolean containsUser(List<User> userList, String username) {
+        if (userList != null) {
+            for (User user : userList) {
+                if (user.getPrimaryKey().equals(username)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/EditActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/EditActivity.java
index 0710b7d7c..2e1ff5e06 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/EditActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/EditActivity.java
@@ -25,13 +25,12 @@ import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ActivityEditBinding;
 import it.niedermann.nextcloud.deck.model.Account;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedActivity;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedAlertDialogBuilder;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
 import it.niedermann.nextcloud.deck.util.CardUtil;
 
-import static android.graphics.Color.parseColor;
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.applyBrandToPrimaryTabLayout;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
@@ -45,7 +44,6 @@ public class EditActivity extends BrandedActivity {
 
     private ActivityEditBinding binding;
     private EditCardViewModel viewModel;
-    private SyncManager syncManager;
 
     private static final int[] tabTitles = new int[]{
             R.string.card_edit_details,
@@ -83,7 +81,6 @@ public class EditActivity extends BrandedActivity {
         setSupportActionBar(binding.toolbar);
 
         viewModel = new ViewModelProvider(this).get(EditCardViewModel.class);
-        syncManager = new SyncManager(this);
 
         loadDataFromIntent();
     }
@@ -120,8 +117,8 @@ public class EditActivity extends BrandedActivity {
 
         final long boardId = args.getLong(BUNDLE_KEY_BOARD_ID);
 
-        observeOnce(syncManager.getFullBoardById(account.getId(), boardId), EditActivity.this, (fullBoard -> {
-            applyBrand(parseColor('#' + fullBoard.getBoard().getColor()));
+        observeOnce(viewModel.getFullBoardById(account.getId(), boardId), EditActivity.this, (fullBoard -> {
+            applyBrand(fullBoard.getBoard().getColor());
             viewModel.setCanEdit(fullBoard.getBoard().isPermissionEdit());
             invalidateOptionsMenu();
             if (viewModel.isCreateMode()) {
@@ -138,7 +135,7 @@ public class EditActivity extends BrandedActivity {
                 setupViewPager();
                 setupTitle();
             } else {
-                observeOnce(syncManager.getCardByLocalId(account.getId(), cardId), EditActivity.this, (fullCard) -> {
+                observeOnce(viewModel.getFullCardWithProjectsByLocalId(account.getId(), cardId), EditActivity.this, (fullCard) -> {
                     if (fullCard == null) {
                         new BrandedAlertDialogBuilder(this)
                                 .setTitle(R.string.card_not_found)
@@ -154,6 +151,8 @@ public class EditActivity extends BrandedActivity {
                 });
             }
         }));
+
+        DeckLog.verbose("Finished loading intent data: { accountId = " + viewModel.getAccount().getId() + " , cardId = " + cardId + " }");
     }
 
     @Override
@@ -170,12 +169,16 @@ public class EditActivity extends BrandedActivity {
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         if (item.getItemId() == R.id.action_card_save) {
-            saveAndFinish();
+            saveAndRun(super::finish);
         }
         return super.onOptionsItemSelected(item);
     }
 
-    private void saveAndFinish() {
+    /**
+     * Tries to save the current {@link FullCard} from the {@link EditCardViewModel} and then runs the given {@link Runnable}
+     * @param runnable
+     */
+    private void saveAndRun(@NonNull Runnable runnable) {
         if (!viewModel.isPendingCreation()) {
             viewModel.setPendingCreation(true);
             final String title = viewModel.getFullCard().getCard().getTitle();
@@ -193,9 +196,9 @@ public class EditActivity extends BrandedActivity {
                         .show();
             } else {
                 if (viewModel.isCreateMode()) {
-                    observeOnce(syncManager.createFullCard(viewModel.getAccount().getId(), viewModel.getBoardId(), viewModel.getFullCard().getCard().getStackId(), viewModel.getFullCard()), EditActivity.this, (card) -> super.finish());
+                    observeOnce(viewModel.createFullCard(viewModel.getAccount().getId(), viewModel.getBoardId(), viewModel.getFullCard().getCard().getStackId(), viewModel.getFullCard()), EditActivity.this, (card) -> runnable.run());
                 } else {
-                    observeOnce(syncManager.updateCard(viewModel.getFullCard()), EditActivity.this, (card) -> super.finish());
+                    observeOnce(viewModel.updateCard(viewModel.getFullCard()), EditActivity.this, (card) -> runnable.run());
                 }
             }
         }
@@ -264,26 +267,15 @@ public class EditActivity extends BrandedActivity {
     }
 
     @Override
-    public boolean onSupportNavigateUp() {
-        finish(); // close this activity as oppose to navigating up
-        return true;
-    }
-
-    @Override
-    public void onBackPressed() {
-        finish();
-    }
-
-    @Override
     public void finish() {
         if (!viewModel.hasChanges() && viewModel.canEdit()) {
             new BrandedAlertDialogBuilder(this)
                     .setTitle(R.string.simple_save)
                     .setMessage(R.string.do_you_want_to_save_your_changes)
-                    .setPositiveButton(R.string.simple_save, (dialog, whichButton) -> saveAndFinish())
+                    .setPositiveButton(R.string.simple_save, (dialog, whichButton) -> saveAndRun(super::finish))
                     .setNegativeButton(R.string.simple_discard, (dialog, whichButton) -> super.finish()).show();
         } else {
-            directFinish();
+            super.finish();
         }
     }
 
@@ -296,10 +288,10 @@ public class EditActivity extends BrandedActivity {
 
     @Override
     public void applyBrand(int mainColor) {
-        if(isBrandingEnabled(this)) {
+        if (isBrandingEnabled(this)) {
             final Drawable navigationIcon = binding.toolbar.getNavigationIcon();
             if (navigationIcon == null) {
-                DeckLog.error("Excpected navigationIcon to be present.");
+                DeckLog.error("Expected navigationIcon to be present.");
             } else {
                 DrawableCompat.setTint(binding.toolbar.getNavigationIcon(), colorAccent);
             }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/EditCardViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/EditCardViewModel.java
index c8c93c838..c754d0800 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/EditCardViewModel.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/EditCardViewModel.java
@@ -1,38 +1,57 @@
 package it.niedermann.nextcloud.deck.ui.card;
 
+import android.app.Application;
+
 import androidx.annotation.NonNull;
-import androidx.lifecycle.ViewModel;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
 
+import java.io.File;
 import java.util.ArrayList;
+import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Attachment;
+import it.niedermann.nextcloud.deck.model.Board;
 import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.model.Label;
+import it.niedermann.nextcloud.deck.model.full.FullBoard;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.model.full.FullCardWithProjects;
+import it.niedermann.nextcloud.deck.model.ocs.Activity;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 
 @SuppressWarnings("WeakerAccess")
-public class EditCardViewModel extends ViewModel {
+public class EditCardViewModel extends AndroidViewModel {
 
+    private SyncManager syncManager;
     private Account account;
     private long boardId;
-    private FullCard originalCard;
-    private FullCard fullCard;
+    private FullCardWithProjects originalCard;
+    private FullCardWithProjects fullCard;
     private boolean isSupportedVersion = false;
     private boolean hasCommentsAbility = false;
     private boolean pendingCreation = false;
     private boolean canEdit = false;
     private boolean createMode = false;
 
+    public EditCardViewModel(@NonNull Application application) {
+        super(application);
+        this.syncManager = new SyncManager(application);
+    }
+
     /**
      * Stores a deep copy of the given fullCard to be able to compare the state at every time in #{@link EditCardViewModel#hasChanges()}
      *
      * @param boardId  Local ID, expecting a positive long value
      * @param fullCard The card that is currently edited
      */
-    public void initializeExistingCard(long boardId, @NonNull FullCard fullCard, boolean isSupportedVersion) {
+    public void initializeExistingCard(long boardId, @NonNull FullCardWithProjects fullCard, boolean isSupportedVersion) {
         this.boardId = boardId;
         this.fullCard = fullCard;
-        this.originalCard = new FullCard(this.fullCard);
+        this.originalCard = new FullCardWithProjects(this.fullCard);
         this.isSupportedVersion = isSupportedVersion;
     }
 
@@ -43,7 +62,7 @@ public class EditCardViewModel extends ViewModel {
      * @param stackId Local ID, expecting a positive long value where the card should be created
      */
     public void initializeNewCard(long boardId, long stackId, boolean isSupportedVersion) {
-        final FullCard fullCard = new FullCard();
+        final FullCardWithProjects fullCard = new FullCardWithProjects();
         fullCard.setLabels(new ArrayList<>());
         fullCard.setAssignedUsers(new ArrayList<>());
         fullCard.setAttachments(new ArrayList<>());
@@ -55,11 +74,12 @@ public class EditCardViewModel extends ViewModel {
 
     public void setAccount(@NonNull Account account) {
         this.account = account;
+        this.syncManager = new SyncManager(getApplication(), account.getName());
         hasCommentsAbility = account.getServerDeckVersionAsObject().supportsComments();
     }
 
     public boolean hasChanges() {
-        if(fullCard == null) {
+        if (fullCard == null) {
             DeckLog.info("Can not check for changes because fullCard is null → assuming no changes have been made yet.");
             return false;
         }
@@ -74,7 +94,7 @@ public class EditCardViewModel extends ViewModel {
         return account;
     }
 
-    public FullCard getFullCard() {
+    public FullCardWithProjects getFullCard() {
         return fullCard;
     }
 
@@ -105,4 +125,44 @@ public class EditCardViewModel extends ViewModel {
     public long getBoardId() {
         return boardId;
     }
+
+    public LiveData<FullBoard> getFullBoardById(Long accountId, Long localId) {
+        return syncManager.getFullBoardById(accountId, localId);
+    }
+
+    public WrappedLiveData<Label> createLabel(long accountId, Label label, long localBoardId) {
+        return syncManager.createLabel(accountId, label, localBoardId);
+    }
+
+    public LiveData<FullCardWithProjects> getFullCardWithProjectsByLocalId(long accountId, long cardLocalId) {
+        return syncManager.getFullCardWithProjectsByLocalId(accountId, cardLocalId);
+    }
+
+    public WrappedLiveData<FullCard> createFullCard(long accountId, long localBoardId, long localStackId, @NonNull FullCard card) {
+        return syncManager.createFullCard(accountId, localBoardId, localStackId, card);
+    }
+
+    public WrappedLiveData<FullCard> updateCard(@NonNull FullCard card) {
+        return syncManager.updateCard(card);
+    }
+
+    public LiveData<List<Activity>> syncActivitiesForCard(@NonNull Card card) {
+        return syncManager.syncActivitiesForCard(card);
+    }
+
+    public WrappedLiveData<Attachment> addAttachmentToCard(long accountId, long localCardId, @NonNull String mimeType, @NonNull File file) {
+        return syncManager.addAttachmentToCard(accountId, localCardId, mimeType, file);
+    }
+
+    public WrappedLiveData<Void> deleteAttachmentOfCard(long accountId, long localCardId, long localAttachmentId) {
+        return syncManager.deleteAttachmentOfCard(accountId, localCardId, localAttachmentId);
+    }
+
+    public LiveData<Card> getCardByRemoteID(long accountId, long remoteId) {
+        return syncManager.getCardByRemoteID(accountId, remoteId);
+    }
+
+    public LiveData<Board> getBoardByRemoteId(long accountId, long remoteId) {
+        return syncManager.getBoardByRemoteId(accountId, remoteId);
+    }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/ItemCardViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/ItemCardViewHolder.java
deleted file mode 100644
index c9e41c37f..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/ItemCardViewHolder.java
+++ /dev/null
@@ -1,15 +0,0 @@
-package it.niedermann.nextcloud.deck.ui.card;
-
-import androidx.recyclerview.widget.RecyclerView;
-
-import it.niedermann.nextcloud.deck.databinding.ItemCardBinding;
-
-public class ItemCardViewHolder extends RecyclerView.ViewHolder {
-    public ItemCardBinding binding;
-
-    @SuppressWarnings("WeakerAccess")
-    public ItemCardViewHolder(ItemCardBinding binding) {
-        super(binding.getRoot());
-        this.binding = binding;
-    }
-}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/LabelAutoCompleteAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/LabelAutoCompleteAdapter.java
index f77282e11..fe974f2a0 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/LabelAutoCompleteAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/LabelAutoCompleteAdapter.java
@@ -9,6 +9,7 @@ import android.view.ViewGroup;
 import android.widget.Filter;
 
 import androidx.activity.ComponentActivity;
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.core.graphics.drawable.DrawableCompat;
@@ -18,11 +19,11 @@ import java.util.Collection;
 import java.util.List;
 import java.util.Random;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemAutocompleteLabelBinding;
 import it.niedermann.nextcloud.deck.model.Label;
 import it.niedermann.nextcloud.deck.util.AutoCompleteAdapter;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
 
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 
@@ -35,7 +36,7 @@ public class LabelAutoCompleteAdapter extends AutoCompleteAdapter<Label> {
     public LabelAutoCompleteAdapter(@NonNull ComponentActivity activity, long accountId, long boardId, long cardId) {
         super(activity, accountId, boardId, cardId);
         final String[] colors = activity.getResources().getStringArray(R.array.board_default_colors);
-        final String createLabelColor = colors[new Random().nextInt(colors.length)].substring(1);
+        @ColorInt int createLabelColor = Color.parseColor(colors[new Random().nextInt(colors.length)]);
         observeOnce(syncManager.getFullBoardById(accountId, boardId), activity, (fullBoard) -> {
             if (fullBoard.getBoard().isPermissionManage()) {
                 canManage = true;
@@ -59,8 +60,8 @@ public class LabelAutoCompleteAdapter extends AutoCompleteAdapter<Label> {
         }
 
         final Label label = getItem(position);
-        final int labelColor = Color.parseColor("#" + label.getColor());
-        final int color = ColorUtil.getForegroundColorForBackgroundColor(labelColor);
+        final int labelColor = label.getColor();
+        final int color = ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(labelColor);
 
         binding.label.setText(label.getTitle());
         binding.label.setChipBackgroundColor(ColorStateList.valueOf(labelColor));
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/UserAutoCompleteAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/UserAutoCompleteAdapter.java
index d2fd4d40d..473ad06c1 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/UserAutoCompleteAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/UserAutoCompleteAdapter.java
@@ -8,6 +8,7 @@ import android.widget.Filter;
 import androidx.activity.ComponentActivity;
 import androidx.annotation.NonNull;
 import androidx.lifecycle.LiveData;
+import androidx.lifecycle.Observer;
 
 import java.util.List;
 
@@ -15,14 +16,16 @@ import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemAutocompleteUserBinding;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.extrawurst.UserSearchLiveData;
 import it.niedermann.nextcloud.deck.util.AutoCompleteAdapter;
 import it.niedermann.nextcloud.deck.util.ViewUtil;
 
-import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
-
 public class UserAutoCompleteAdapter extends AutoCompleteAdapter<User> {
     @NonNull
     private Account account;
+    private UserSearchLiveData liveSearchForACL;
+    private LiveData<List<User>> liveData;
+    private Observer<List<User>> observer;
 
     public UserAutoCompleteAdapter(@NonNull ComponentActivity activity, @NonNull Account account, long boardId) {
         this(activity, account, boardId, NO_CARD);
@@ -31,6 +34,7 @@ public class UserAutoCompleteAdapter extends AutoCompleteAdapter<User> {
     public UserAutoCompleteAdapter(@NonNull ComponentActivity activity, @NonNull Account account, long boardId, long cardId) {
         super(activity, account.getId(), boardId, cardId);
         this.account = account;
+        this.liveSearchForACL = syncManager.searchUserByUidOrDisplayNameForACL();
     }
 
     @Override
@@ -56,23 +60,24 @@ public class UserAutoCompleteAdapter extends AutoCompleteAdapter<User> {
             protected FilterResults performFiltering(CharSequence constraint) {
                 if (constraint != null) {
                     activity.runOnUiThread(() -> {
-                        LiveData<List<User>> liveData;
                         final int constraintLength = constraint.toString().trim().length();
                         if (cardId == NO_CARD) {
                             liveData = constraintLength > 0
-                                    ? syncManager.searchUserByUidOrDisplayNameForACL(accountId, boardId, constraint.toString())
+                                    ? liveSearchForACL.search(accountId, boardId, constraint.toString())
                                     : syncManager.findProposalsForUsersToAssignForACL(accountId, boardId, activity.getResources().getInteger(R.integer.max_users_suggested));
                         } else {
                             liveData = constraintLength > 0
                                     ? syncManager.searchUserByUidOrDisplayName(accountId, boardId, cardId, constraint.toString())
                                     : syncManager.findProposalsForUsersToAssign(accountId, boardId, cardId, activity.getResources().getInteger(R.integer.max_users_suggested));
                         }
-                        observeOnce(liveData, activity, users -> {
+                        liveData.removeObservers(activity);
+                        observer = users -> {
                             users.removeAll(itemsToExclude);
                             filterResults.values = users;
                             filterResults.count = users.size();
                             publishResults(constraint, filterResults);
-                        });
+                        };
+                        liveData.observe(activity, observer);
                     });
                 }
                 return filterResults;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/activities/CardActivityFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/activities/CardActivityFragment.java
index 08d960257..f95eea89f 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/activities/CardActivityFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/activities/CardActivityFragment.java
@@ -8,11 +8,9 @@ import android.view.ViewGroup;
 import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
 import androidx.lifecycle.ViewModelProvider;
-import androidx.recyclerview.widget.RecyclerView;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.databinding.FragmentCardEditTabActivitiesBinding;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
 
 public class CardActivityFragment extends Fragment {
@@ -39,17 +37,14 @@ public class CardActivityFragment extends Fragment {
         }
 
         if (!viewModel.isCreateMode()) {
-            final SyncManager syncManager = new SyncManager(requireContext());
-
-            syncManager.syncActivitiesForCard(viewModel.getFullCard().getCard()).observe(getViewLifecycleOwner(), (activities -> {
+            viewModel.syncActivitiesForCard(viewModel.getFullCard().getCard()).observe(getViewLifecycleOwner(), (activities -> {
                 if (activities == null || activities.size() == 0) {
                     binding.emptyContentView.setVisibility(View.VISIBLE);
                     binding.activitiesList.setVisibility(View.GONE);
                 } else {
                     binding.emptyContentView.setVisibility(View.GONE);
                     binding.activitiesList.setVisibility(View.VISIBLE);
-                    RecyclerView.Adapter adapter = new CardActivityAdapter(activities, requireActivity().getMenuInflater());
-                    binding.activitiesList.setAdapter(adapter);
+                    binding.activitiesList.setAdapter(new CardActivityAdapter(activities, requireActivity().getMenuInflater()));
                 }
             }));
         } else {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/activities/CardActivityViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/activities/CardActivityViewHolder.java
index 7d49b932d..6362f90dd 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/activities/CardActivityViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/activities/CardActivityViewHolder.java
@@ -3,17 +3,18 @@ package it.niedermann.nextcloud.deck.ui.card.activities;
 import android.content.Context;
 import android.view.MenuInflater;
 import android.view.View;
+import android.widget.ImageView;
 
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
 
+import it.niedermann.android.util.ClipboardUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemActivityBinding;
 import it.niedermann.nextcloud.deck.model.enums.ActivityType;
 import it.niedermann.nextcloud.deck.model.ocs.Activity;
 import it.niedermann.nextcloud.deck.util.DateUtil;
-
-import static it.niedermann.nextcloud.deck.util.ClipboardUtil.copyToClipboard;
+import it.niedermann.nextcloud.deck.util.ViewUtil;
 
 public class CardActivityViewHolder extends RecyclerView.ViewHolder {
     public ItemActivityBinding binding;
@@ -26,38 +27,61 @@ public class CardActivityViewHolder extends RecyclerView.ViewHolder {
 
     public void bind(@NonNull Activity activity, @NonNull MenuInflater inflater) {
         final Context context = itemView.getContext();
-        binding.date.setText(DateUtil.getRelativeDateTimeString(context, activity.getLastModified().getTime()));
+        binding.date.setText(DateUtil.getRelativeDateTimeString(context, activity.getLastModified().toEpochMilli()));
         binding.subject.setText(activity.getSubject());
         itemView.setOnClickListener(View::showContextMenu);
         itemView.setOnCreateContextMenuListener((menu, v, menuInfo) -> {
             inflater.inflate(R.menu.activity_menu, menu);
-            menu.findItem(android.R.id.copy).setOnMenuItemClickListener(item -> copyToClipboard(context, activity.getSubject()));
+            menu.findItem(android.R.id.copy).setOnMenuItemClickListener(item -> ClipboardUtil.INSTANCE.copyToClipboard(context, activity.getSubject()));
         });
-        switch (ActivityType.findById(activity.getType())) {
+        final ActivityType type = ActivityType.findById(activity.getType());
+        setImageResource(binding.type, type);
+        setImageColor(context, binding.type, type);
+    }
+
+    private static void setImageResource(@NonNull ImageView imageView, @NonNull ActivityType type) {
+        switch (type) {
             case CHANGE:
-                binding.type.setImageResource(R.drawable.type_change_36dp);
+                imageView.setImageResource(R.drawable.type_change_36dp);
                 break;
             case ADD:
-                binding.type.setImageResource(R.drawable.type_add_color_36dp);
+                imageView.setImageResource(R.drawable.type_add_color_36dp);
                 break;
             case DELETE:
-                binding.type.setImageResource(R.drawable.type_delete_color_36dp);
+                imageView.setImageResource(R.drawable.type_delete_color_36dp);
                 break;
             case ARCHIVE:
-                binding.type.setImageResource(R.drawable.type_archive_grey600_36dp);
+                imageView.setImageResource(R.drawable.type_archive_grey600_36dp);
                 break;
             case TAGGED_WITH_LABEL:
-                binding.type.setImageResource(R.drawable.type_label_grey600_36dp);
+                imageView.setImageResource(R.drawable.type_label_grey600_36dp);
                 break;
             case COMMENT:
-                binding.type.setImageResource(R.drawable.type_comment_grey600_36dp);
+                imageView.setImageResource(R.drawable.type_comment_grey600_36dp);
                 break;
             case FILES:
-                binding.type.setImageResource(R.drawable.type_file_36dp);
+                imageView.setImageResource(R.drawable.type_file_36dp);
+                break;
             case HISTORY:
-                binding.type.setImageResource(R.drawable.type_file_36dp);
+                imageView.setImageResource(R.drawable.type_history_36dp);
+                break;
             case DECK:
             default:
+                imageView.setImageResource(R.drawable.ic_app_logo);
+                break;
+        }
+    }
+
+    private static void setImageColor(@NonNull Context context, @NonNull ImageView imageView, @NonNull ActivityType type) {
+        switch (type) {
+            case ADD:
+                ViewUtil.setImageColor(context, imageView, R.color.activity_create);
+                break;
+            case DELETE:
+                ViewUtil.setImageColor(context, imageView, R.color.activity_delete);
+                break;
+            default:
+                ViewUtil.setImageColor(context, imageView, R.color.grey600);
                 break;
         }
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeDialog.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeDialog.java
new file mode 100644
index 000000000..34d2eb3f3
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeDialog.java
@@ -0,0 +1,113 @@
+package it.niedermann.nextcloud.deck.ui.card.assignee;
+
+import android.app.Dialog;
+import android.content.Context;
+import android.graphics.Color;
+import android.net.Uri;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.appcompat.app.AlertDialog;
+import androidx.fragment.app.DialogFragment;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.swiperefreshlayout.widget.CircularProgressDrawable;
+
+import com.bumptech.glide.Glide;
+
+import java.io.Serializable;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.DialogPreviewBinding;
+import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedDeleteAlertDialogBuilder;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
+import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
+
+import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
+
+@Deprecated
+public class CardAssigneeDialog extends BrandedDialogFragment {
+
+    private static final String KEY_USER = "user";
+    private DialogPreviewBinding binding;
+    private EditCardViewModel viewModel;
+
+    @Nullable
+    private CardAssigneeListener cardAssigneeListener = null;
+    @SuppressWarnings("NotNullFieldNotInitialized")
+    @NonNull
+    private User user;
+
+    @Override
+    public void onAttach(@NonNull Context context) {
+        super.onAttach(context);
+
+        if (getParentFragment() instanceof CardAssigneeListener) {
+            this.cardAssigneeListener = (CardAssigneeListener) getParentFragment();
+        } else if (context instanceof CardAssigneeListener) {
+            this.cardAssigneeListener = (CardAssigneeListener) context;
+        }
+
+        final Bundle args = requireArguments();
+        if (!args.containsKey(KEY_USER)) {
+            throw new IllegalArgumentException("Provide at least " + KEY_USER);
+        }
+        final Serializable user = args.getSerializable(KEY_USER);
+        if (user == null) {
+            throw new IllegalArgumentException(KEY_USER + " must not be null.");
+        }
+        this.user = (User) user;
+    }
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        binding = DialogPreviewBinding.inflate(LayoutInflater.from(requireContext()));
+        viewModel = new ViewModelProvider(requireActivity()).get(EditCardViewModel.class);
+
+        AlertDialog.Builder dialogBuilder = new BrandedDeleteAlertDialogBuilder(requireContext());
+
+        if (viewModel.canEdit() && cardAssigneeListener != null) {
+            dialogBuilder.setPositiveButton(R.string.simple_unassign, (d, w) -> cardAssigneeListener.onUnassignUser(user));
+        }
+
+        return dialogBuilder
+                .setView(binding.getRoot())
+                .setNeutralButton(R.string.simple_close, null)
+                .create();
+    }
+
+    @Override
+    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+        super.onActivityCreated(savedInstanceState);
+
+        final Context context = requireContext();
+
+        final CircularProgressDrawable circularProgressDrawable = new CircularProgressDrawable(context);
+        circularProgressDrawable.setStrokeWidth(5f);
+        circularProgressDrawable.setCenterRadius(30f);
+        circularProgressDrawable.setColorSchemeColors(isDarkTheme(context) ? Color.LTGRAY : Color.DKGRAY);
+        circularProgressDrawable.start();
+
+        binding.avatar.post(() -> Glide.with(binding.avatar.getContext())
+                .load(viewModel.getAccount().getUrl() + "/index.php/avatar/" + Uri.encode(user.getUid()) + "/" + binding.avatar.getWidth())
+                .placeholder(circularProgressDrawable)
+                .error(R.drawable.ic_person_grey600_24dp)
+                .into(binding.avatar));
+        binding.title.setText(user.getDisplayname());
+    }
+
+    @Override
+    public void applyBrand(int mainColor) {
+    }
+
+    public static DialogFragment newInstance(@NonNull User user) {
+        final DialogFragment fragment = new CardAssigneeDialog();
+        final Bundle args = new Bundle();
+        args.putSerializable(KEY_USER, user);
+        fragment.setArguments(args);
+        return fragment;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeListener.java
new file mode 100644
index 000000000..259a8b57c
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/assignee/CardAssigneeListener.java
@@ -0,0 +1,11 @@
+package it.niedermann.nextcloud.deck.ui.card.assignee;
+
+import androidx.annotation.NonNull;
+
+import it.niedermann.nextcloud.deck.model.User;
+
+public interface CardAssigneeListener {
+
+    void onUnassignUser(@NonNull User user);
+
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/AttachmentDeletedListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/AttachmentDeletedListener.java
index c236fa4c5..2d3ece255 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/AttachmentDeletedListener.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/AttachmentDeletedListener.java
@@ -3,5 +3,5 @@ package it.niedermann.nextcloud.deck.ui.card.attachments;
 import it.niedermann.nextcloud.deck.model.Attachment;
 
 public interface AttachmentDeletedListener {
-        void onAttachmentDeleted(Attachment attachment);
-    }
\ No newline at end of file
+    void onAttachmentDeleted(Attachment attachment);
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/AttachmentViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/AttachmentViewHolder.java
index ed3031b7c..533bbe322 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/AttachmentViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/AttachmentViewHolder.java
@@ -1,18 +1,59 @@
 package it.niedermann.nextcloud.deck.ui.card.attachments;
 
+import android.view.MenuInflater;
 import android.view.View;
 import android.widget.ImageView;
 
+import androidx.annotation.CallSuper;
 import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.graphics.drawable.DrawableCompat;
+import androidx.fragment.app.FragmentManager;
 import androidx.recyclerview.widget.RecyclerView;
 
+import it.niedermann.android.util.ClipboardUtil;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Attachment;
+import it.niedermann.nextcloud.deck.model.enums.DBStatus;
+import it.niedermann.nextcloud.deck.ui.branding.BrandingUtil;
+import it.niedermann.nextcloud.deck.util.AttachmentUtil;
+
 public abstract class AttachmentViewHolder extends RecyclerView.ViewHolder {
     AttachmentViewHolder(@NonNull View itemView) {
         super(itemView);
     }
 
+    public void bind(@NonNull Account account, @NonNull MenuInflater menuInflater, @NonNull FragmentManager fragmentManager, Long cardRemoteId, Attachment attachment, @Nullable View.OnClickListener onClickListener, @ColorInt int mainColor) {
+        bind(menuInflater, fragmentManager, cardRemoteId, attachment, onClickListener, mainColor, AttachmentUtil.getRemoteOrLocalUrl(account.getUrl(), cardRemoteId, attachment));
+    }
+
+    @CallSuper
+    public void bind(@NonNull MenuInflater menuInflater, @NonNull FragmentManager fragmentManager, Long cardRemoteId, Attachment attachment, @Nullable View.OnClickListener onClickListener, @ColorInt int mainColor, @Nullable String attachmentUri) {
+        setNotSyncedYetStatus(!DBStatus.LOCAL_EDITED.equals(attachment.getStatusEnum()), mainColor);
+        itemView.setOnCreateContextMenuListener((menu, v, menuInfo) -> {
+            menuInflater.inflate(R.menu.attachment_menu, menu);
+            menu.findItem(R.id.delete).setOnMenuItemClickListener(item -> {
+                DeleteAttachmentDialogFragment.newInstance(attachment).show(fragmentManager, DeleteAttachmentDialogFragment.class.getCanonicalName());
+                return false;
+            });
+            if (attachmentUri == null || attachment.getId() == null || cardRemoteId == null) {
+                menu.findItem(android.R.id.copyUrl).setVisible(false);
+            } else {
+                menu.findItem(android.R.id.copyUrl).setVisible(true);
+                menu.findItem(android.R.id.copyUrl).setOnMenuItemClickListener(item -> ClipboardUtil.INSTANCE.copyToClipboard(itemView.getContext(), attachment.getFilename(), attachmentUri));
+            }
+        });
+    }
+
     abstract protected ImageView getPreview();
 
-    abstract protected void setNotSyncedYetStatus(boolean synced, @ColorInt int color);
+    protected void setNotSyncedYetStatus(boolean synced, @ColorInt int mainColor) {
+        final ImageView notSyncedYet = getNotSyncedYetStatusIcon();
+        DrawableCompat.setTint(notSyncedYet.getDrawable(), BrandingUtil.getSecondaryForegroundColorDependingOnTheme(notSyncedYet.getContext(), mainColor));
+        notSyncedYet.setVisibility(synced ? View.GONE : View.VISIBLE);
+    }
+
+    abstract protected ImageView getNotSyncedYetStatusIcon();
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentAdapter.java
index a72ed8ef2..d601f6bbd 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentAdapter.java
@@ -3,9 +3,7 @@ package it.niedermann.nextcloud.deck.ui.card.attachments;
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
-import android.net.Uri;
 import android.os.Build;
-import android.text.format.Formatter;
 import android.view.LayoutInflater;
 import android.view.MenuInflater;
 import android.view.View;
@@ -16,10 +14,10 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.core.app.ActivityOptionsCompat;
 import androidx.fragment.app.FragmentManager;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
 import androidx.recyclerview.widget.RecyclerView;
 
-import com.bumptech.glide.Glide;
-
 import java.util.ArrayList;
 import java.util.List;
 
@@ -28,21 +26,23 @@ import it.niedermann.nextcloud.deck.databinding.ItemAttachmentDefaultBinding;
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentImageBinding;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
-import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 import it.niedermann.nextcloud.deck.ui.attachments.AttachmentsActivity;
-import it.niedermann.nextcloud.deck.util.AttachmentUtil;
-import it.niedermann.nextcloud.deck.util.DateUtil;
+import it.niedermann.nextcloud.deck.ui.branding.Branded;
 import it.niedermann.nextcloud.deck.util.MimeTypeUtil;
 
+import static androidx.lifecycle.Transformations.distinctUntilChanged;
 import static androidx.recyclerview.widget.RecyclerView.NO_ID;
-import static it.niedermann.nextcloud.deck.util.ClipboardUtil.copyToClipboard;
+import static it.niedermann.nextcloud.deck.util.AttachmentUtil.openAttachmentInBrowser;
 
 @SuppressWarnings("WeakerAccess")
-public class CardAttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHolder> {
+public class CardAttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHolder> implements Branded {
 
     public static final int VIEW_TYPE_DEFAULT = 2;
     public static final int VIEW_TYPE_IMAGE = 1;
 
+    @NonNull
+    private final MutableLiveData<Boolean> isEmpty = new MutableLiveData<>(true);
+    @NonNull
     private final MenuInflater menuInflater;
     @ColorInt
     private int mainColor;
@@ -51,17 +51,16 @@ public class CardAttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHo
     private Long cardRemoteId = null;
     private final long cardLocalId;
     @NonNull
-    FragmentManager fragmentManager;
+    private final FragmentManager fragmentManager;
+    @NonNull
+    private final List<Attachment> attachments = new ArrayList<>();
     @NonNull
-    private List<Attachment> attachments = new ArrayList<>();
-    @Nullable
     private final AttachmentClickedListener attachmentClickedListener;
 
     CardAttachmentAdapter(
-            @NonNull Context context,
             @NonNull FragmentManager fragmentManager,
             @NonNull MenuInflater menuInflater,
-            @Nullable AttachmentClickedListener attachmentClickedListener,
+            @NonNull AttachmentClickedListener attachmentClickedListener,
             @NonNull Account account,
             @Nullable Long cardLocalId
     ) {
@@ -95,39 +94,14 @@ public class CardAttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHo
 
     @Override
     public void onBindViewHolder(@NonNull AttachmentViewHolder holder, int position) {
-        final Context context = holder.itemView.getContext();
         final Attachment attachment = attachments.get(position);
-        final int viewType = getItemViewType(position);
-
-        @Nullable final String uri = (attachment.getId() == null || cardRemoteId == null)
-                ? attachment.getLocalPath() :
-                AttachmentUtil.getRemoteUrl(account.getUrl(), cardRemoteId, attachment.getId());
-        holder.setNotSyncedYetStatus(!DBStatus.LOCAL_EDITED.equals(attachment.getStatusEnum()), mainColor);
-        holder.itemView.setOnCreateContextMenuListener((menu, v, menuInfo) -> {
-            menuInflater.inflate(R.menu.attachment_menu, menu);
-            menu.findItem(R.id.delete).setOnMenuItemClickListener(item -> {
-                DeleteAttachmentDialogFragment.newInstance(attachment).show(fragmentManager, DeleteAttachmentDialogFragment.class.getCanonicalName());
-                return false;
-            });
-            if (uri == null) {
-                menu.findItem(android.R.id.copyUrl).setVisible(false);
-            } else {
-                menu.findItem(android.R.id.copyUrl).setOnMenuItemClickListener(item -> copyToClipboard(context, attachment.getFilename(), uri));
-            }
-        });
+        final Context context = holder.itemView.getContext();
+        final View.OnClickListener onClickListener;
 
-        switch (viewType) {
+        switch (getItemViewType(position)) {
             case VIEW_TYPE_IMAGE: {
-                holder.getPreview().setImageResource(R.drawable.ic_image_grey600_24dp);
-                Glide.with(context)
-                        .load(uri)
-                        .placeholder(R.drawable.ic_image_grey600_24dp)
-                        .error(R.drawable.ic_image_grey600_24dp)
-                        .into(holder.getPreview());
-                holder.itemView.setOnClickListener((v) -> {
-                    if (attachmentClickedListener != null) {
-                        attachmentClickedListener.onAttachmentClicked(position);
-                    }
+                onClickListener = (event) -> {
+                    attachmentClickedListener.onAttachmentClicked(position);
                     final Intent intent = AttachmentsActivity.createIntent(context, account, cardLocalId, attachment.getLocalId());
                     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && context instanceof Activity) {
                         String transitionName = context.getString(R.string.transition_attachment_preview, String.valueOf(attachment.getLocalId()));
@@ -136,46 +110,16 @@ public class CardAttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHo
                     } else {
                         context.startActivity(intent);
                     }
-                });
+                };
                 break;
             }
             case VIEW_TYPE_DEFAULT:
             default: {
-                DefaultAttachmentViewHolder defaultHolder = (DefaultAttachmentViewHolder) holder;
-
-                if (MimeTypeUtil.isAudio(attachment.getMimetype())) {
-                    holder.getPreview().setImageResource(R.drawable.ic_music_note_grey600_24dp);
-                } else if (MimeTypeUtil.isVideo(attachment.getMimetype())) {
-                    holder.getPreview().setImageResource(R.drawable.ic_local_movies_grey600_24dp);
-                } else if (MimeTypeUtil.isPdf(attachment.getMimetype())) {
-                    holder.getPreview().setImageResource(R.drawable.ic_baseline_picture_as_pdf_24);
-                } else if (MimeTypeUtil.isContact(attachment.getMimetype())) {
-                    holder.getPreview().setImageResource(R.drawable.ic_baseline_contact_mail_24);
-                } else {
-                    holder.getPreview().setImageResource(R.drawable.ic_attach_file_grey600_24dp);
-                }
-
-                if (cardRemoteId != null) {
-                    defaultHolder.itemView.setOnClickListener((event) -> {
-                        Intent openURL = new Intent(Intent.ACTION_VIEW);
-                        openURL.setData(Uri.parse(AttachmentUtil.getRemoteUrl(account.getUrl(), cardRemoteId, attachment.getId())));
-                        context.startActivity(openURL);
-                    });
-                }
-                defaultHolder.binding.filename.setText(attachment.getBasename());
-                defaultHolder.binding.filesize.setText(Formatter.formatFileSize(context, attachment.getFilesize()));
-                if (attachment.getLastModifiedLocal() != null) {
-                    defaultHolder.binding.modified.setText(DateUtil.getRelativeDateTimeString(context, attachment.getLastModifiedLocal().getTime()));
-                    defaultHolder.binding.modified.setVisibility(View.VISIBLE);
-                } else if (attachment.getLastModified() != null) {
-                    defaultHolder.binding.modified.setText(DateUtil.getRelativeDateTimeString(context, attachment.getLastModified().getTime()));
-                    defaultHolder.binding.modified.setVisibility(View.VISIBLE);
-                } else {
-                    defaultHolder.binding.modified.setVisibility(View.GONE);
-                }
+                onClickListener = (event) -> openAttachmentInBrowser(context, account.getUrl(), cardRemoteId, attachment.getId());
                 break;
             }
         }
+        holder.bind(account, menuInflater, fragmentManager, cardRemoteId, attachment, onClickListener, mainColor);
     }
 
     @Override
@@ -188,21 +132,46 @@ public class CardAttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHo
         return attachments.size();
     }
 
+    private void updateIsEmpty() {
+        this.isEmpty.postValue(getItemCount() <= 0);
+    }
+
+    @NonNull
+    public LiveData<Boolean> isEmpty() {
+        return distinctUntilChanged(this.isEmpty);
+    }
+
     public void setAttachments(@NonNull List<Attachment> attachments, @Nullable Long cardRemoteId) {
         this.cardRemoteId = cardRemoteId;
         this.attachments.clear();
         this.attachments.addAll(attachments);
         notifyDataSetChanged();
+        this.updateIsEmpty();
     }
 
     public void addAttachment(Attachment a) {
-        this.attachments.add(a);
+        this.attachments.add(0, a);
         notifyItemInserted(this.attachments.size());
+        this.updateIsEmpty();
     }
 
     public void removeAttachment(Attachment a) {
         final int index = this.attachments.indexOf(a);
         this.attachments.remove(a);
         notifyItemRemoved(index);
+        this.updateIsEmpty();
+    }
+
+    public void replaceAttachment(Attachment toReplace, Attachment with) {
+        final int index = this.attachments.indexOf(toReplace);
+        this.attachments.remove(toReplace);
+        this.attachments.add(index, with);
+        notifyItemChanged(index);
+    }
+
+    @Override
+    public void applyBrand(@ColorInt int mainColor) {
+        this.mainColor = mainColor;
+        notifyDataSetChanged();
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsBottomsheetBehaviorCallback.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsBottomsheetBehaviorCallback.java
new file mode 100644
index 000000000..6b60bbffd
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsBottomsheetBehaviorCallback.java
@@ -0,0 +1,91 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments;
+
+import android.content.Context;
+import android.view.View;
+
+import androidx.activity.OnBackPressedCallback;
+import androidx.annotation.ColorInt;
+import androidx.annotation.ColorRes;
+import androidx.annotation.DimenRes;
+import androidx.annotation.NonNull;
+import androidx.annotation.Px;
+import androidx.core.content.ContextCompat;
+
+import com.google.android.material.animation.ArgbEvaluatorCompat;
+import com.google.android.material.bottomnavigation.BottomNavigationView;
+import com.google.android.material.bottomsheet.BottomSheetBehavior;
+import com.google.android.material.floatingactionbutton.FloatingActionButton;
+
+import it.niedermann.android.util.DimensionUtil;
+
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
+import static com.google.android.material.bottomsheet.BottomSheetBehavior.STATE_HIDDEN;
+
+public class CardAttachmentsBottomsheetBehaviorCallback extends BottomSheetBehavior.BottomSheetCallback {
+    @NonNull
+    private final OnBackPressedCallback backPressedCallback;
+    @NonNull
+    private final FloatingActionButton fab;
+    @NonNull
+    private final View pickerBackdrop;
+    @NonNull
+    private final BottomNavigationView bottomNavigation;
+    @ColorInt
+    private final int backdropColorExpanded;
+    @ColorInt
+    private final int backdropColorCollapsed;
+    @Px
+    private final int bottomNavigationHeight;
+
+    private float lastOffset = -1;
+
+    public CardAttachmentsBottomsheetBehaviorCallback(@NonNull Context context,
+                                                      @NonNull OnBackPressedCallback backPressedCallback,
+                                                      @NonNull FloatingActionButton fab,
+                                                      @NonNull View pickerBackdrop,
+                                                      @NonNull BottomNavigationView bottomNavigation,
+                                                      @ColorRes int backdropColorExpanded,
+                                                      @ColorRes int backdropColorCollapsed,
+                                                      @DimenRes int bottomNavigationHeight
+    ) {
+        this.backPressedCallback = backPressedCallback;
+        this.fab = fab;
+        this.pickerBackdrop = pickerBackdrop;
+        this.bottomNavigation = bottomNavigation;
+        this.backdropColorExpanded = ContextCompat.getColor(context, backdropColorExpanded);
+        this.backdropColorCollapsed = ContextCompat.getColor(context, backdropColorCollapsed);
+        this.bottomNavigationHeight = DimensionUtil.INSTANCE.dpToPx(context, bottomNavigationHeight);
+    }
+
+    @Override
+    public void onStateChanged(@NonNull View bottomSheet, int newState) {
+        if (newState == STATE_HIDDEN) {
+            backPressedCallback.setEnabled(false);
+            if (pickerBackdrop.getVisibility() != GONE) {
+                pickerBackdrop.setVisibility(GONE);
+            }
+        } else if (pickerBackdrop.getVisibility() != VISIBLE) {
+            pickerBackdrop.setVisibility(VISIBLE);
+        }
+    }
+
+    @Override
+    public void onSlide(@NonNull View bottomSheet, float slideOffset) {
+        if (slideOffset <= 0) {
+            final float bottomSheetPercentageShown = slideOffset * -1;
+            pickerBackdrop.setBackgroundColor(ArgbEvaluatorCompat.getInstance().evaluate(bottomSheetPercentageShown, backdropColorExpanded, backdropColorCollapsed));
+            bottomNavigation.setTranslationY(bottomSheetPercentageShown * bottomNavigationHeight);
+            if (slideOffset <= lastOffset && slideOffset != 0) {
+                if (fab.getVisibility() == GONE) {
+                    fab.show();
+                }
+            } else {
+                if (fab.getVisibility() == VISIBLE) {
+                    fab.hide();
+                }
+            }
+        }
+        lastOffset = slideOffset;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsFragment.java
index c291c5bdf..07e8d39dd 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsFragment.java
@@ -1,35 +1,42 @@
 package it.niedermann.nextcloud.deck.ui.card.attachments;
 
-import android.Manifest;
-import android.app.Activity;
 import android.content.ContentResolver;
+import android.content.Context;
 import android.content.Intent;
+import android.content.res.ColorStateList;
 import android.net.Uri;
-import android.os.Build;
 import android.os.Bundle;
+import android.provider.ContactsContract;
 import android.util.DisplayMetrics;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.LinearLayout;
+import android.widget.Toast;
 
+import androidx.activity.OnBackPressedCallback;
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.annotation.RequiresApi;
 import androidx.core.app.SharedElementCallback;
+import androidx.core.content.ContextCompat;
 import androidx.fragment.app.Fragment;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.recyclerview.widget.GridLayoutManager;
+import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 
+import com.google.android.material.bottomsheet.BottomSheetBehavior;
 import com.google.android.material.snackbar.Snackbar;
 import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
 
 import java.io.File;
 import java.io.IOException;
-import java.util.Date;
+import java.time.Instant;
 import java.util.List;
 import java.util.Map;
 
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.FragmentCardEditTabAttachmentsBinding;
@@ -41,10 +48,36 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiv
 import it.niedermann.nextcloud.deck.ui.branding.BrandedFragment;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedSnackbar;
 import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
+import it.niedermann.nextcloud.deck.ui.card.attachments.picker.AbstractPickerAdapter;
+import it.niedermann.nextcloud.deck.ui.card.attachments.picker.ContactAdapter;
+import it.niedermann.nextcloud.deck.ui.card.attachments.picker.FileAdapter;
+import it.niedermann.nextcloud.deck.ui.card.attachments.picker.FileAdapterLegacy;
+import it.niedermann.nextcloud.deck.ui.card.attachments.picker.GalleryAdapter;
+import it.niedermann.nextcloud.deck.ui.card.attachments.picker.GalleryItemDecoration;
+import it.niedermann.nextcloud.deck.ui.card.attachments.previewdialog.PreviewDialog;
+import it.niedermann.nextcloud.deck.ui.card.attachments.previewdialog.PreviewDialogViewModel;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
-
+import it.niedermann.nextcloud.deck.ui.takephoto.TakePhotoActivity;
+import it.niedermann.nextcloud.deck.util.DeckColorUtil;
+import it.niedermann.nextcloud.deck.util.VCardUtil;
+
+import static android.Manifest.permission.CAMERA;
+import static android.Manifest.permission.READ_CONTACTS;
+import static android.Manifest.permission.READ_EXTERNAL_STORAGE;
+import static android.app.Activity.RESULT_OK;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.Build.VERSION_CODES.LOLLIPOP;
+import static android.os.Build.VERSION_CODES.M;
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
+import static androidx.core.content.PermissionChecker.PERMISSION_GRANTED;
+import static androidx.core.content.PermissionChecker.checkSelfPermission;
+import static com.google.android.material.bottomsheet.BottomSheetBehavior.STATE_COLLAPSED;
+import static com.google.android.material.bottomsheet.BottomSheetBehavior.STATE_HIDDEN;
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.applyBrandToFAB;
+import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
+import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMainColor;
 import static it.niedermann.nextcloud.deck.ui.card.attachments.CardAttachmentAdapter.VIEW_TYPE_DEFAULT;
 import static it.niedermann.nextcloud.deck.ui.card.attachments.CardAttachmentAdapter.VIEW_TYPE_IMAGE;
 import static it.niedermann.nextcloud.deck.util.AttachmentUtil.copyContentUriToTempFile;
@@ -53,14 +86,35 @@ import static java.net.HttpURLConnection.HTTP_CONFLICT;
 public class CardAttachmentsFragment extends BrandedFragment implements AttachmentDeletedListener, AttachmentClickedListener {
 
     private FragmentCardEditTabAttachmentsBinding binding;
-    private EditCardViewModel viewModel;
+    private EditCardViewModel editViewModel;
+    private PreviewDialogViewModel previewViewModel;
+    private BottomSheetBehavior<LinearLayout> mBottomSheetBehaviour;
+
+    private RecyclerView.ItemDecoration galleryItemDecoration;
+
+    private static final int REQUEST_CODE_PICK_FILE = 1;
+    private static final int REQUEST_CODE_PICK_FILE_PERMISSION = 2;
+    private static final int REQUEST_CODE_PICK_CAMERA = 3;
+    private static final int REQUEST_CODE_PICK_GALLERY_PERMISSION = 4;
+    private static final int REQUEST_CODE_PICK_CONTACT = 5;
+    private static final int REQUEST_CODE_PICK_CONTACT_PICKER_PERMISSION = 6;
 
-    private static final int REQUEST_CODE_ADD_ATTACHMENT = 1;
-    private static final int REQUEST_PERMISSION = 2;
+    @ColorInt
+    private int accentColor;
+    @ColorInt
+    private int primaryColor;
 
-    private SyncManager syncManager;
     private CardAttachmentAdapter adapter;
 
+    private AbstractPickerAdapter<?> pickerAdapter;
+
+    private final OnBackPressedCallback backPressedCallback = new OnBackPressedCallback(true) {
+        @Override
+        public void handleOnBackPressed() {
+            mBottomSheetBehaviour.setState(STATE_HIDDEN);
+        }
+    };
+
     private int clickedItemPosition;
 
     @Override
@@ -69,30 +123,58 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                              Bundle savedInstanceState) {
 
         binding = FragmentCardEditTabAttachmentsBinding.inflate(inflater, container, false);
-        viewModel = new ViewModelProvider(requireActivity()).get(EditCardViewModel.class);
+        editViewModel = new ViewModelProvider(requireActivity()).get(EditCardViewModel.class);
+        previewViewModel = new ViewModelProvider(requireActivity()).get(PreviewDialogViewModel.class);
+        binding.bottomNavigation.setOnNavigationItemSelectedListener(item -> {
+            if (item.getItemId() == R.id.gallery) {
+                showGalleryPicker();
+            } else if (item.getItemId() == R.id.contacts) {
+                showContactPicker();
+            } else if (item.getItemId() == R.id.files) {
+                showFilePicker();
+            }
+            return true;
+        });
+        accentColor = ContextCompat.getColor(requireContext(), R.color.accent);
+        primaryColor = ContextCompat.getColor(requireContext(), R.color.primary);
 
         // This might be a zombie fragment with an empty EditCardViewModel after Android killed the activity (but not the fragment instance
         // See https://github.com/stefan-niedermann/nextcloud-deck/issues/478
-        if (viewModel.getFullCard() == null) {
+        if (editViewModel.getFullCard() == null) {
             DeckLog.logError(new IllegalStateException("Cannot populate " + CardAttachmentsFragment.class.getSimpleName() + " because viewModel.getFullCard() is null"));
             return binding.getRoot();
         }
 
-        syncManager = new SyncManager(requireContext());
         adapter = new CardAttachmentAdapter(
-                requireContext(),
                 getChildFragmentManager(),
                 requireActivity().getMenuInflater(),
                 this,
-                viewModel.getAccount(),
-                viewModel.getFullCard().getLocalId());
+                editViewModel.getAccount(),
+                editViewModel.getFullCard().getLocalId());
         binding.attachmentsList.setAdapter(adapter);
 
-        updateEmptyContentView();
+        adapter.isEmpty().observe(getViewLifecycleOwner(), (isEmpty) -> {
+            if (isEmpty) {
+                this.binding.emptyContentView.setVisibility(VISIBLE);
+                this.binding.attachmentsList.setVisibility(GONE);
+            } else {
+                this.binding.emptyContentView.setVisibility(GONE);
+                this.binding.attachmentsList.setVisibility(VISIBLE);
+            }
+        });
+        galleryItemDecoration = new GalleryItemDecoration(DimensionUtil.INSTANCE.dpToPx(requireContext(), R.dimen.spacer_1qx));
+        mBottomSheetBehaviour = BottomSheetBehavior.from(binding.bottomSheetParent);
+        mBottomSheetBehaviour.setDraggable(true);
+        mBottomSheetBehaviour.setHideable(true);
+        mBottomSheetBehaviour.setState(STATE_HIDDEN);
+        mBottomSheetBehaviour.addBottomSheetCallback(new CardAttachmentsBottomsheetBehaviorCallback(
+                requireContext(), backPressedCallback, binding.fab, binding.pickerBackdrop, binding.bottomNavigation,
+                R.color.mdtp_transparent_black, android.R.color.transparent, R.dimen.attachments_bottom_navigation_height));
+        binding.pickerBackdrop.setOnClickListener(v -> mBottomSheetBehaviour.setState(STATE_HIDDEN));
 
         final DisplayMetrics displayMetrics = getResources().getDisplayMetrics();
-        int spanCount = (int) ((displayMetrics.widthPixels / displayMetrics.density) / getResources().getInteger(R.integer.max_dp_attachment_column));
-        GridLayoutManager glm = new GridLayoutManager(getContext(), spanCount);
+        final int spanCount = (int) ((displayMetrics.widthPixels / displayMetrics.density) / getResources().getInteger(R.integer.max_dp_attachment_column));
+        final GridLayoutManager glm = new GridLayoutManager(getContext(), spanCount);
         glm.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
             @Override
             public int getSpanSize(int position) {
@@ -106,7 +188,7 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
             }
         });
         binding.attachmentsList.setLayoutManager(glm);
-        if (!viewModel.isCreateMode()) {
+        if (!editViewModel.isCreateMode()) {
             // https://android-developers.googleblog.com/2018/02/continuous-shared-element-transitions.html?m=1
             // https://github.com/android/animation-samples/blob/master/GridToPager/app/src/main/java/com/google/samples/gridtopager/fragment/ImagePagerFragment.java
             setExitSharedElementCallback(new SharedElementCallback() {
@@ -119,17 +201,19 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                     }
                 }
             });
-            adapter.setAttachments(viewModel.getFullCard().getAttachments(), viewModel.getFullCard().getId());
-            updateEmptyContentView();
+            adapter.setAttachments(editViewModel.getFullCard().getAttachments(), editViewModel.getFullCard().getId());
         }
 
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT && viewModel.canEdit()) {
+        if (editViewModel.canEdit()) {
             binding.fab.setOnClickListener(v -> {
-                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-                    requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
-                            REQUEST_PERMISSION);
+                if (SDK_INT < LOLLIPOP) {
+                    openNativeFilePicker();
                 } else {
-                    startFilePickerIntent();
+                    binding.bottomNavigation.setSelectedItemId(R.id.gallery);
+                    showGalleryPicker();
+                    mBottomSheetBehaviour.setState(STATE_COLLAPSED);
+                    backPressedCallback.setEnabled(true);
+                    requireActivity().getOnBackPressedDispatcher().addCallback(getViewLifecycleOwner(), backPressedCallback);
                 }
             });
             binding.fab.show();
@@ -146,116 +230,281 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
             binding.fab.hide();
             binding.emptyContentView.hideDescription();
         }
+        @Nullable Context context = requireContext();
+        applyBrand(isBrandingEnabled(context)
+                ? readBrandMainColor(context)
+                : ContextCompat.getColor(context, R.color.defaultBrand));
         return binding.getRoot();
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
-    private void startFilePickerIntent() {
-        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
-        intent.addCategory(Intent.CATEGORY_OPENABLE);
-        intent.setType("*/*");
-        startActivityForResult(intent, REQUEST_CODE_ADD_ATTACHMENT);
+    @Override
+    public void onPause() {
+        super.onPause();
+        backPressedCallback.setEnabled(false);
     }
 
     @Override
-    public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
-        super.onActivityResult(requestCode, resultCode, data);
-        if (requestCode == REQUEST_CODE_ADD_ATTACHMENT && resultCode == Activity.RESULT_OK) {
-            if (data == null) {
-                ExceptionDialogFragment.newInstance(new UploadAttachmentFailedException("Intent data is null"), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
-                return;
+    public void onResume() {
+        super.onResume();
+        backPressedCallback.setEnabled(binding.bottomNavigation.getTranslationY() == 0);
+    }
+
+    private void showGalleryPicker() {
+        if (!(pickerAdapter instanceof GalleryAdapter)) {
+            if (isPermissionRequestNeeded(READ_EXTERNAL_STORAGE) || isPermissionRequestNeeded(CAMERA)) {
+                requestPermissions(new String[]{READ_EXTERNAL_STORAGE, CAMERA}, REQUEST_CODE_PICK_GALLERY_PERMISSION);
+            } else {
+                unbindPickerAdapter();
+                pickerAdapter = new GalleryAdapter(requireContext(), (uri, pair) -> {
+                    previewViewModel.prepareDialog(pair.first, pair.second);
+                    PreviewDialog.newInstance().show(getChildFragmentManager(), PreviewDialog.class.getSimpleName());
+                    observeOnce(previewViewModel.getResult(), getViewLifecycleOwner(), (submitPositive) -> {
+                        if (submitPositive) {
+                            onActivityResult(REQUEST_CODE_PICK_FILE, RESULT_OK, new Intent().setData(uri));
+                        }
+                    });
+                }, this::openNativeCameraPicker, getViewLifecycleOwner());
+                if (binding.pickerRecyclerView.getItemDecorationCount() == 0) {
+                    binding.pickerRecyclerView.addItemDecoration(galleryItemDecoration);
+                }
+                binding.pickerRecyclerView.setLayoutManager(new GridLayoutManager(requireContext(), 3));
+                binding.pickerRecyclerView.setAdapter(pickerAdapter);
             }
-            final Uri sourceUri = data.getData();
-            if (sourceUri == null) {
-                ExceptionDialogFragment.newInstance(new UploadAttachmentFailedException("sourceUri is null"), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
-                return;
+        }
+    }
+
+    private void showContactPicker() {
+        if (!(pickerAdapter instanceof ContactAdapter)) {
+            if (isPermissionRequestNeeded(READ_CONTACTS)) {
+                requestPermissions(new String[]{READ_CONTACTS}, REQUEST_CODE_PICK_CONTACT_PICKER_PERMISSION);
+            } else {
+                unbindPickerAdapter();
+                pickerAdapter = new ContactAdapter(requireContext(), (uri, pair) -> {
+                    previewViewModel.prepareDialog(pair.first, pair.second);
+                    PreviewDialog.newInstance().show(getChildFragmentManager(), PreviewDialog.class.getSimpleName());
+                    observeOnce(previewViewModel.getResult(), getViewLifecycleOwner(), (submitPositive) -> {
+                        if (submitPositive) {
+                            onActivityResult(REQUEST_CODE_PICK_CONTACT, RESULT_OK, new Intent().setData(uri));
+                        }
+                    });
+                }, this::openNativeContactPicker);
+                removeGalleryItemDecoration();
+                binding.pickerRecyclerView.setLayoutManager(new LinearLayoutManager(requireContext()));
+                binding.pickerRecyclerView.setAdapter(pickerAdapter);
             }
-            if (!ContentResolver.SCHEME_CONTENT.equals(sourceUri.getScheme())) {
-                ExceptionDialogFragment.newInstance(new UploadAttachmentFailedException("Unknown URI scheme: " + sourceUri.getScheme()), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
-                return;
+        }
+    }
+
+    private void showFilePicker() {
+        if (!(pickerAdapter instanceof FileAdapter) && !(pickerAdapter instanceof FileAdapterLegacy)) {
+            if (isPermissionRequestNeeded(READ_EXTERNAL_STORAGE)) {
+                requestPermissions(new String[]{READ_EXTERNAL_STORAGE}, REQUEST_CODE_PICK_FILE_PERMISSION);
+            } else {
+                unbindPickerAdapter();
+                if (SDK_INT >= LOLLIPOP) {
+//                    if (SDK_INT >= Build.VERSION_CODES.Q) {
+//                        // TODO Only usable with Scoped Storage
+//                        pickerAdapter = new FileAdapter(requireContext(), uri -> onActivityResult(REQUEST_CODE_PICK_FILE, RESULT_OK, new Intent().setData(uri)), this::openNativeFilePicker);
+//                    } else {
+                    pickerAdapter = new FileAdapterLegacy((uri, pair) -> {
+                        previewViewModel.prepareDialog(pair.first, pair.second);
+                        PreviewDialog.newInstance().show(getChildFragmentManager(), PreviewDialog.class.getSimpleName());
+                        observeOnce(previewViewModel.getResult(), getViewLifecycleOwner(), (submitPositive) -> {
+                            if (submitPositive) {
+                                onActivityResult(REQUEST_CODE_PICK_FILE, RESULT_OK, new Intent().setData(uri));
+                            }
+                        });
+                    }, this::openNativeFilePicker);
+//                    }
+                    removeGalleryItemDecoration();
+                    binding.pickerRecyclerView.setLayoutManager(new LinearLayoutManager(requireContext()));
+                    binding.pickerRecyclerView.setAdapter(pickerAdapter);
+                }
             }
+        }
+    }
 
-            DeckLog.verbose("--- found content URL " + sourceUri.getPath());
-            File fileToUpload;
+    private void openNativeCameraPicker() {
+        if (SDK_INT >= LOLLIPOP) {
+            startActivityForResult(TakePhotoActivity.createIntent(requireContext()), REQUEST_CODE_PICK_CAMERA);
+        } else {
+            ExceptionDialogFragment.newInstance(new UnsupportedOperationException("This feature requires Android 5"), editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+        }
+    }
 
-            try {
-                DeckLog.verbose("---- so, now copy & upload: " + sourceUri.getPath());
-                fileToUpload = copyContentUriToTempFile(requireContext(), sourceUri, viewModel.getAccount().getId(), viewModel.getFullCard().getCard().getLocalId());
-            } catch (IllegalArgumentException | IOException e) {
-                ExceptionDialogFragment.newInstance(new UploadAttachmentFailedException("Could not copy content URI to temporary file", e), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
-                return;
-            }
+    private void openNativeContactPicker() {
+        final Intent intent = new Intent(Intent.ACTION_PICK).setType(ContactsContract.Contacts.CONTENT_TYPE);
+        if (intent.resolveActivity(requireContext().getPackageManager()) != null) {
+            startActivityForResult(intent, REQUEST_CODE_PICK_CONTACT);
+        }
+    }
+
+    private void openNativeFilePicker() {
+        startActivityForResult(new Intent(Intent.ACTION_GET_CONTENT)
+                .addCategory(Intent.CATEGORY_OPENABLE)
+                .setType("*/*"), REQUEST_CODE_PICK_FILE);
+    }
+
+    /**
+     * Checks the current Android version and whether the permission has already been granted.
+     *
+     * @param permission see {@link android.Manifest.permission}
+     * @return whether or not requesting permission is needed
+     */
+    private boolean isPermissionRequestNeeded(@NonNull String permission) {
+        return SDK_INT >= M && checkSelfPermission(requireActivity(), permission) != PERMISSION_GRANTED;
+    }
+
+    private void unbindPickerAdapter() {
+        if (pickerAdapter != null) {
+            pickerAdapter.onDestroy();
+        }
+    }
+
+    private void removeGalleryItemDecoration() {
+        if (binding.pickerRecyclerView.getItemDecorationCount() > 0) {
+            binding.pickerRecyclerView.removeItemDecoration(galleryItemDecoration);
+        }
+    }
 
-            for (Attachment existingAttachment : viewModel.getFullCard().getAttachments()) {
-                final String existingPath = existingAttachment.getLocalPath();
-                if (existingPath != null && existingPath.equals(fileToUpload.getAbsolutePath())) {
-                    BrandedSnackbar.make(binding.coordinatorLayout, R.string.attachment_already_exists, Snackbar.LENGTH_LONG).show();
-                    return;
+    @Override
+    public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+        switch (requestCode) {
+            case REQUEST_CODE_PICK_CONTACT:
+            case REQUEST_CODE_PICK_CAMERA:
+            case REQUEST_CODE_PICK_FILE: {
+                if (resultCode == RESULT_OK) {
+                    final Uri sourceUri = requestCode == REQUEST_CODE_PICK_CONTACT
+                            ? VCardUtil.getVCardContentUri(requireContext(), Uri.parse(data.getDataString()))
+                            : data.getData();
+                    try {
+                        uploadNewAttachmentFromUri(sourceUri, requestCode == REQUEST_CODE_PICK_CAMERA
+                                ? data.getType()
+                                : requireContext().getContentResolver().getType(sourceUri));
+                        mBottomSheetBehaviour.setState(STATE_HIDDEN);
+                    } catch (Exception e) {
+                        ExceptionDialogFragment.newInstance(e, editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                    }
                 }
+                break;
+            }
+            default: {
+                super.onActivityResult(requestCode, resultCode, data);
             }
+        }
+    }
+
+    @Override
+    public void onDestroy() {
+        if (this.pickerAdapter != null) {
+            this.pickerAdapter.onDestroy();
+            this.binding.pickerRecyclerView.setAdapter(null);
+        }
+        super.onDestroy();
+    }
 
-            final Date now = new Date();
-            final Attachment a = new Attachment();
-            a.setMimetype(requireContext().getContentResolver().getType(sourceUri));
-            a.setData(fileToUpload.getName());
-            a.setFilename(fileToUpload.getName());
-            a.setBasename(fileToUpload.getName());
-            a.setFilesize(fileToUpload.length());
-            a.setLocalPath(fileToUpload.getAbsolutePath());
-            a.setLastModifiedLocal(now);
-            a.setStatusEnum(DBStatus.LOCAL_EDITED);
-            a.setCreatedAt(now);
-            viewModel.getFullCard().getAttachments().add(a);
-            adapter.addAttachment(a);
-            if (!viewModel.isCreateMode()) {
-                WrappedLiveData<Attachment> liveData = syncManager.addAttachmentToCard(viewModel.getAccount().getId(), viewModel.getFullCard().getLocalId(), a.getMimetype(), fileToUpload);
-                observeOnce(liveData, getViewLifecycleOwner(), (next) -> {
-                    if (liveData.hasError()) {
-                        Throwable t = liveData.getError();
-                        if (t instanceof NextcloudHttpRequestFailedException && ((NextcloudHttpRequestFailedException) t).getStatusCode() == HTTP_CONFLICT) {
-                            // https://github.com/stefan-niedermann/nextcloud-deck/issues/534
-                            viewModel.getFullCard().getAttachments().remove(a);
-                            adapter.removeAttachment(a);
-                            BrandedSnackbar.make(binding.coordinatorLayout, R.string.attachment_already_exists, Snackbar.LENGTH_LONG).show();
+    private void uploadNewAttachmentFromUri(@NonNull Uri sourceUri, String mimeType) throws UploadAttachmentFailedException, IOException {
+        if (sourceUri == null) {
+            throw new UploadAttachmentFailedException("sourceUri is null");
+        }
+        switch (sourceUri.getScheme()) {
+            case ContentResolver.SCHEME_CONTENT:
+            case ContentResolver.SCHEME_FILE: {
+                DeckLog.verbose("--- found content URL " + sourceUri.getPath());
+                final File fileToUpload = copyContentUriToTempFile(requireContext(), sourceUri, editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId());
+                for (Attachment existingAttachment : editViewModel.getFullCard().getAttachments()) {
+                    final String existingPath = existingAttachment.getLocalPath();
+                    if (existingPath != null && existingPath.equals(fileToUpload.getAbsolutePath())) {
+                        BrandedSnackbar.make(binding.coordinatorLayout, R.string.attachment_already_exists, Snackbar.LENGTH_LONG).show();
+                        return;
+                    }
+                }
+                final Instant now = Instant.now();
+                final Attachment a = new Attachment();
+                a.setMimetype(mimeType);
+                a.setData(fileToUpload.getName());
+                a.setFilename(fileToUpload.getName());
+                a.setBasename(fileToUpload.getName());
+                a.setFilesize(fileToUpload.length());
+                a.setLocalPath(fileToUpload.getAbsolutePath());
+                a.setLastModifiedLocal(now);
+                a.setCreatedAt(now);
+                a.setStatusEnum(DBStatus.LOCAL_EDITED);
+                editViewModel.getFullCard().getAttachments().add(0, a);
+                adapter.addAttachment(a);
+                if (!editViewModel.isCreateMode()) {
+                    WrappedLiveData<Attachment> liveData = editViewModel.addAttachmentToCard(editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId(), a.getMimetype(), fileToUpload);
+                    observeOnce(liveData, getViewLifecycleOwner(), (next) -> {
+                        if (liveData.hasError()) {
+                            Throwable t = liveData.getError();
+                            if (t instanceof NextcloudHttpRequestFailedException && ((NextcloudHttpRequestFailedException) t).getStatusCode() == HTTP_CONFLICT) {
+                                // https://github.com/stefan-niedermann/nextcloud-deck/issues/534
+                                editViewModel.getFullCard().getAttachments().remove(a);
+                                adapter.removeAttachment(a);
+                                BrandedSnackbar.make(binding.coordinatorLayout, R.string.attachment_already_exists, Snackbar.LENGTH_LONG).show();
+                            } else {
+                                ExceptionDialogFragment.newInstance(new UploadAttachmentFailedException("Unknown URI scheme", t), editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                            }
                         } else {
-                            ExceptionDialogFragment.newInstance(new UploadAttachmentFailedException("Unknown URI scheme", t), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                            editViewModel.getFullCard().getAttachments().remove(a);
+                            editViewModel.getFullCard().getAttachments().add(0, next);
+                            adapter.replaceAttachment(a, next);
                         }
-                    } else {
-                        viewModel.getFullCard().getAttachments().remove(a);
-                        adapter.removeAttachment(a);
-                        viewModel.getFullCard().getAttachments().add(next);
-                        adapter.addAttachment(next);
-                    }
-                });
+                    });
+                }
+                break;
+            }
+            default: {
+                throw new UploadAttachmentFailedException("Unknown URI scheme: " + sourceUri.getScheme());
             }
-            updateEmptyContentView();
         }
-
     }
 
     @Override
     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
-        if (requestCode == REQUEST_PERMISSION) {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
-                startFilePickerIntent();
+        switch (requestCode) {
+            case REQUEST_CODE_PICK_FILE_PERMISSION: {
+                if (checkSelfPermission(requireActivity(), READ_EXTERNAL_STORAGE) == PERMISSION_GRANTED) {
+                    showFilePicker();
+                } else {
+                    Toast.makeText(requireContext(), R.string.cannot_upload_files_without_permission, Toast.LENGTH_LONG).show();
+                }
+                break;
             }
-        } else {
-            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
+            case REQUEST_CODE_PICK_GALLERY_PERMISSION: {
+                if (checkSelfPermission(requireActivity(), READ_EXTERNAL_STORAGE) == PERMISSION_GRANTED && checkSelfPermission(requireActivity(), CAMERA) == PERMISSION_GRANTED) {
+                    showGalleryPicker();
+                } else {
+                    Toast.makeText(requireContext(), R.string.cannot_upload_files_without_permission, Toast.LENGTH_LONG).show();
+                }
+                break;
+            }
+            case REQUEST_CODE_PICK_CONTACT_PICKER_PERMISSION: {
+                if (checkSelfPermission(requireActivity(), READ_CONTACTS) == PERMISSION_GRANTED) {
+                    showContactPicker();
+                } else {
+                    Toast.makeText(requireContext(), R.string.cannot_upload_files_without_permission, Toast.LENGTH_LONG).show();
+                }
+                break;
+            }
+            default:
+                super.onRequestPermissionsResult(requestCode, permissions, grantResults);
         }
     }
 
-    public static Fragment newInstance() {
-        return new CardAttachmentsFragment();
-    }
-
     @Override
     public void onAttachmentDeleted(Attachment attachment) {
         adapter.removeAttachment(attachment);
-        viewModel.getFullCard().getAttachments().remove(attachment);
-        if (!viewModel.isCreateMode() && attachment.getLocalId() != null) {
-            syncManager.deleteAttachmentOfCard(viewModel.getAccount().getId(), viewModel.getFullCard().getLocalId(), attachment.getLocalId());
+        editViewModel.getFullCard().getAttachments().remove(attachment);
+        if (!editViewModel.isCreateMode() && attachment.getLocalId() != null) {
+            final WrappedLiveData<Void> deleteLiveData = editViewModel.deleteAttachmentOfCard(editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId(), attachment.getLocalId());
+            observeOnce(deleteLiveData, this, (next) -> {
+                if (deleteLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteLiveData.getError())) {
+                    ExceptionDialogFragment.newInstance(deleteLiveData.getError(), editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                }
+            });
         }
-        updateEmptyContentView();
     }
 
     @Override
@@ -263,19 +512,28 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
         this.clickedItemPosition = position;
     }
 
-
-    private void updateEmptyContentView() {
-        if (this.adapter == null || this.adapter.getItemCount() == 0) {
-            this.binding.emptyContentView.setVisibility(View.VISIBLE);
-            this.binding.attachmentsList.setVisibility(View.GONE);
-        } else {
-            this.binding.emptyContentView.setVisibility(View.GONE);
-            this.binding.attachmentsList.setVisibility(View.VISIBLE);
-        }
-    }
-
     @Override
     public void applyBrand(int mainColor) {
         applyBrandToFAB(mainColor, binding.fab);
+        adapter.applyBrand(mainColor);
+        @ColorInt final int finalMainColor = DeckColorUtil.contrastRatioIsSufficient(mainColor, primaryColor)
+                ? mainColor
+                : accentColor;
+        final ColorStateList list = new ColorStateList(
+                new int[][]{
+                        new int[]{android.R.attr.state_checked},
+                        new int[]{}
+                },
+                new int[]{
+                        finalMainColor,
+                        accentColor
+                }
+        );
+        binding.bottomNavigation.setItemIconTintList(list);
+        binding.bottomNavigation.setItemTextColor(list);
+    }
+
+    public static Fragment newInstance() {
+        return new CardAttachmentsFragment();
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/DefaultAttachmentViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/DefaultAttachmentViewHolder.java
index 7acdd390e..2b5358eb9 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/DefaultAttachmentViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/DefaultAttachmentViewHolder.java
@@ -1,15 +1,25 @@
 package it.niedermann.nextcloud.deck.ui.card.attachments;
 
+import android.text.format.Formatter;
+import android.view.MenuInflater;
 import android.view.View;
 import android.widget.ImageView;
 
 import androidx.annotation.ColorInt;
-import androidx.core.graphics.drawable.DrawableCompat;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.FragmentManager;
 
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentDefaultBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Attachment;
+import it.niedermann.nextcloud.deck.util.DateUtil;
+
+import static it.niedermann.nextcloud.deck.util.AttachmentUtil.getIconForMimeType;
+import static it.niedermann.nextcloud.deck.util.AttachmentUtil.openAttachmentInBrowser;
 
 public class DefaultAttachmentViewHolder extends AttachmentViewHolder {
-    ItemAttachmentDefaultBinding binding;
+    private final ItemAttachmentDefaultBinding binding;
 
     @SuppressWarnings("WeakerAccess")
     public DefaultAttachmentViewHolder(ItemAttachmentDefaultBinding binding) {
@@ -23,8 +33,24 @@ public class DefaultAttachmentViewHolder extends AttachmentViewHolder {
     }
 
     @Override
-    protected void setNotSyncedYetStatus(boolean synced, @ColorInt int mainColor) {
-        DrawableCompat.setTint(binding.notSyncedYet.getDrawable(), mainColor);
-        binding.notSyncedYet.setVisibility(synced ? View.GONE : View.VISIBLE);
+    protected ImageView getNotSyncedYetStatusIcon() {
+        return binding.notSyncedYet;
+    }
+
+    public void bind(@NonNull Account account, @NonNull MenuInflater menuInflater, @NonNull FragmentManager fragmentManager, Long cardRemoteId, Attachment attachment, @Nullable View.OnClickListener onClickListener, @ColorInt int mainColor) {
+        super.bind(account, menuInflater, fragmentManager, cardRemoteId, attachment, onClickListener, mainColor);
+        getPreview().setImageResource(getIconForMimeType(attachment.getMimetype()));
+        itemView.setOnClickListener((event) -> openAttachmentInBrowser(itemView.getContext(), account.getUrl(), cardRemoteId, attachment.getId()));
+        binding.filename.setText(attachment.getBasename());
+        binding.filesize.setText(Formatter.formatFileSize(binding.filesize.getContext(), attachment.getFilesize()));
+        if (attachment.getLastModifiedLocal() != null) {
+            binding.modified.setText(DateUtil.getRelativeDateTimeString(binding.modified.getContext(), attachment.getLastModifiedLocal().toEpochMilli()));
+            binding.modified.setVisibility(View.VISIBLE);
+        } else if (attachment.getLastModified() != null) {
+            binding.modified.setText(DateUtil.getRelativeDateTimeString(binding.modified.getContext(), attachment.getLastModified().toEpochMilli()));
+            binding.modified.setVisibility(View.VISIBLE);
+        } else {
+            binding.modified.setVisibility(View.GONE);
+        }
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/ImageAttachmentViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/ImageAttachmentViewHolder.java
index d13675a30..3c95da1b7 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/ImageAttachmentViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/ImageAttachmentViewHolder.java
@@ -1,15 +1,24 @@
 package it.niedermann.nextcloud.deck.ui.card.attachments;
 
+import android.view.MenuInflater;
 import android.view.View;
 import android.widget.ImageView;
 
 import androidx.annotation.ColorInt;
-import androidx.core.graphics.drawable.DrawableCompat;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.FragmentManager;
 
+import com.bumptech.glide.Glide;
+
+import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemAttachmentImageBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Attachment;
+import it.niedermann.nextcloud.deck.util.AttachmentUtil;
 
 public class ImageAttachmentViewHolder extends AttachmentViewHolder {
-    private ItemAttachmentImageBinding binding;
+    private final ItemAttachmentImageBinding binding;
 
     @SuppressWarnings("WeakerAccess")
     public ImageAttachmentViewHolder(ItemAttachmentImageBinding binding) {
@@ -23,8 +32,22 @@ public class ImageAttachmentViewHolder extends AttachmentViewHolder {
     }
 
     @Override
-    protected void setNotSyncedYetStatus(boolean synced, @ColorInt int mainColor) {
-        DrawableCompat.setTint(binding.notSyncedYet.getDrawable(), mainColor);
-        binding.notSyncedYet.setVisibility(synced ? View.GONE : View.VISIBLE);
+    protected ImageView getNotSyncedYetStatusIcon() {
+        return binding.notSyncedYet;
+    }
+
+    public void bind(@NonNull Account account, @NonNull MenuInflater menuInflater, @NonNull FragmentManager fragmentManager, Long cardRemoteId, Attachment attachment, @Nullable View.OnClickListener onClickListener, @ColorInt int mainColor) {
+        super.bind(menuInflater, fragmentManager, cardRemoteId, attachment, onClickListener, mainColor, AttachmentUtil.getRemoteOrLocalUrl(account.getUrl(), cardRemoteId, attachment));
+
+        getPreview().post(() -> {
+            @Nullable final String uri = AttachmentUtil.getThumbnailUrl(account.getServerDeckVersionAsObject(), account.getUrl(), cardRemoteId, attachment, getPreview().getWidth());
+            Glide.with(getPreview().getContext())
+                    .load(uri)
+                    .placeholder(R.drawable.ic_image_grey600_24dp)
+                    .error(R.drawable.ic_image_grey600_24dp)
+                    .into(getPreview());
+        });
+
+        itemView.setOnClickListener(onClickListener);
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractCursorPickerAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractCursorPickerAdapter.java
new file mode 100644
index 000000000..a2ea6dd37
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractCursorPickerAdapter.java
@@ -0,0 +1,100 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.database.Cursor;
+import android.graphics.Bitmap;
+import android.net.Uri;
+import android.util.Pair;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.bumptech.glide.RequestBuilder;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.function.BiConsumer;
+
+import static android.database.Cursor.FIELD_TYPE_INTEGER;
+import static android.database.Cursor.FIELD_TYPE_NULL;
+import static androidx.recyclerview.widget.RecyclerView.NO_ID;
+import static java.util.Objects.requireNonNull;
+
+/**
+ * An {@link RecyclerView.Adapter} which provides previews of one type of files and also an option to open a native dialog.
+ * <p>
+ * Example: Previews for images of the gallery as well a one option to take a photo
+ */
+public abstract class AbstractCursorPickerAdapter<T extends RecyclerView.ViewHolder> extends AbstractPickerAdapter<T> {
+
+    private final int count;
+    protected final int columnIndex;
+    private final int columnIndexType;
+    @NonNull
+    protected final BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect;
+    @NonNull
+    protected final Runnable openNativePicker;
+    @NonNull
+    protected final Cursor cursor;
+    @NonNull
+    protected final ContentResolver contentResolver;
+
+    /**
+     * Should be used to bind heavy operations like when dealing with {@link Bitmap}.
+     * This must only be one {@link Thread} because otherwise the cursor might change while fetching data from it.
+     */
+    @NonNull
+    protected final ExecutorService bindExecutor = Executors.newFixedThreadPool(1);
+
+    public AbstractCursorPickerAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker, Uri subject, String idColumn, String sortOrder) {
+        this(context, onSelect, openNativePicker, subject, idColumn, new String[]{idColumn}, sortOrder);
+    }
+
+    public AbstractCursorPickerAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker, Uri subject, String idColumn, String[] requestedColumns, String sortOrder) {
+        this(context, onSelect, openNativePicker, idColumn, requireNonNull(context.getContentResolver().query(subject, requestedColumns, null, null, sortOrder)));
+    }
+
+    public AbstractCursorPickerAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker, String idColumn, @NonNull Cursor cursor) {
+        this.contentResolver = context.getContentResolver();
+        this.onSelect = onSelect;
+        this.openNativePicker = openNativePicker;
+        this.cursor = cursor;
+        this.cursor.moveToFirst();
+        this.columnIndex = this.cursor.getColumnIndex(idColumn);
+        this.count = cursor.getCount() + 1;
+        this.columnIndexType = (this.count > 1) ? this.cursor.getType(columnIndex) : FIELD_TYPE_NULL;
+        setHasStableIds(true);
+    }
+
+    /**
+     * Moves the {@link #cursor} to the given position
+     */
+    @Override
+    public long getItemId(int position) {
+        if (!cursor.isClosed() && cursor.moveToPosition(position - 1)) {
+            //noinspection SwitchStatementWithTooFewBranches
+            switch (columnIndexType) {
+                case FIELD_TYPE_INTEGER:
+                    return cursor.getLong(columnIndex);
+                default:
+                    throw new IllegalStateException("Unknown type for columnIndex \"" + columnIndex + "\": " + columnIndexType);
+            }
+        } else {
+            return NO_ID;
+        }
+    }
+
+    @Override
+    public int getItemCount() {
+        return count;
+    }
+
+    /**
+     * Call this method when the {@link AbstractCursorPickerAdapter} is no longer need to free resources.
+     */
+    public void onDestroy() {
+        cursor.close();
+        bindExecutor.shutdownNow();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractPickerAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractPickerAdapter.java
new file mode 100644
index 000000000..901d204cd
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/AbstractPickerAdapter.java
@@ -0,0 +1,26 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import androidx.recyclerview.widget.RecyclerView;
+
+public abstract class AbstractPickerAdapter<T extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<T> {
+
+    protected static final int VIEW_TYPE_NONE = -1;
+    protected static final int VIEW_TYPE_ITEM = 0;
+    protected static final int VIEW_TYPE_ITEM_NATIVE = 1;
+
+    @Override
+    public int getItemViewType(int position) {
+        if (position > 0) {
+            return VIEW_TYPE_ITEM;
+        } else if (position == 0) {
+            return VIEW_TYPE_ITEM_NATIVE;
+        } else {
+            return VIEW_TYPE_NONE;
+        }
+    }
+
+    /**
+     * Call this method when the {@link AbstractPickerAdapter} is no longer need to free resources.
+     */
+    public abstract void onDestroy();
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactAdapter.java
new file mode 100644
index 000000000..22ac0c694
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactAdapter.java
@@ -0,0 +1,104 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.net.Uri;
+import android.os.Handler;
+import android.os.Looper;
+import android.provider.ContactsContract;
+import android.text.TextUtils;
+import android.util.Pair;
+import android.view.LayoutInflater;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.bumptech.glide.RequestBuilder;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.function.BiConsumer;
+
+import it.niedermann.nextcloud.deck.databinding.ItemPickerNativeBinding;
+import it.niedermann.nextcloud.deck.databinding.ItemPickerUserBinding;
+
+import static android.provider.ContactsContract.CommonDataKinds.Email.DATA;
+import static android.provider.ContactsContract.CommonDataKinds.Phone.LOOKUP_KEY;
+import static android.provider.ContactsContract.CommonDataKinds.Phone.NUMBER;
+import static android.provider.ContactsContract.Contacts.CONTENT_LOOKUP_URI;
+import static android.provider.ContactsContract.Contacts.CONTENT_URI;
+import static android.provider.ContactsContract.Contacts.DISPLAY_NAME;
+import static android.provider.ContactsContract.Contacts.SORT_KEY_PRIMARY;
+import static android.provider.ContactsContract.Contacts._ID;
+
+public class ContactAdapter extends AbstractCursorPickerAdapter<RecyclerView.ViewHolder> {
+
+    private final int lookupKeyColumnIndex;
+    private final int displayNameColumnIndex;
+
+    public ContactAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable onSelectPicker) {
+        super(context, onSelect, onSelectPicker, CONTENT_URI, _ID, new String[]{_ID, LOOKUP_KEY, DISPLAY_NAME}, SORT_KEY_PRIMARY);
+        lookupKeyColumnIndex = cursor.getColumnIndex(LOOKUP_KEY);
+        displayNameColumnIndex = cursor.getColumnIndex(DISPLAY_NAME);
+        notifyItemRangeInserted(0, getItemCount() + 1);
+    }
+
+    @NonNull
+    @Override
+    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        switch (viewType) {
+            case VIEW_TYPE_ITEM_NATIVE:
+                return new ContactNativeItemViewHolder(ItemPickerNativeBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+            case VIEW_TYPE_ITEM:
+                return new ContactItemViewHolder(ItemPickerUserBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+            default:
+                throw new IllegalStateException("Unknown viewType " + viewType);
+        }
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
+        switch (getItemViewType(position)) {
+            case VIEW_TYPE_ITEM_NATIVE: {
+                ((ContactNativeItemViewHolder) holder).bind(openNativePicker);
+                break;
+            }
+            case VIEW_TYPE_ITEM: {
+                final ContactItemViewHolder viewHolder = (ContactItemViewHolder) holder;
+                if (!cursor.isClosed()) {
+                    cursor.moveToPosition(position - 1);
+                    final String displayName = cursor.getString(displayNameColumnIndex);
+                    final String lookupKey = cursor.getString(lookupKeyColumnIndex);
+                    bindExecutor.execute(() -> {
+                        try (InputStream inputStream = ContactsContract.Contacts.openContactPhotoInputStream(contentResolver, Uri.withAppendedPath(CONTENT_LOOKUP_URI, lookupKey))) {
+                            final Bitmap thumbnail = BitmapFactory.decodeStream(inputStream);
+                            String contactInformation = "";
+                            try (final Cursor phoneCursor = contentResolver.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, new String[]{NUMBER}, LOOKUP_KEY + " = ?", new String[]{lookupKey}, null)) {
+                                if (phoneCursor != null && phoneCursor.moveToFirst()) {
+                                    contactInformation = phoneCursor.getString(phoneCursor.getColumnIndex(NUMBER));
+                                }
+                            }
+                            if (TextUtils.isEmpty(contactInformation)) {
+                                try (final Cursor emailCursor = contentResolver.query(ContactsContract.CommonDataKinds.Email.CONTENT_URI, new String[]{DATA}, LOOKUP_KEY + " = ?", new String[]{lookupKey}, null)) {
+                                    if (emailCursor != null && emailCursor.moveToFirst()) {
+                                        contactInformation = emailCursor.getString(emailCursor.getColumnIndex(DATA));
+                                    }
+                                }
+                            }
+                            final String finalContactInformation = contactInformation;
+                            new Handler(Looper.getMainLooper()).post(() -> viewHolder.bind(Uri.withAppendedPath(CONTENT_LOOKUP_URI, lookupKey), thumbnail, displayName, finalContactInformation, onSelect));
+                        } catch (IOException ignored) {
+                            new Handler(Looper.getMainLooper()).post(viewHolder::bindError);
+                        }
+                    });
+                } else {
+                    new Handler(Looper.getMainLooper()).post(viewHolder::bindError);
+                }
+                break;
+            }
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactItemViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactItemViewHolder.java
new file mode 100644
index 000000000..f403fed21
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactItemViewHolder.java
@@ -0,0 +1,66 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import android.graphics.Bitmap;
+import android.graphics.drawable.ColorDrawable;
+import android.net.Uri;
+import android.text.TextUtils;
+import android.util.Pair;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.bumptech.glide.Glide;
+import com.bumptech.glide.RequestBuilder;
+import com.bumptech.glide.request.RequestOptions;
+
+import java.util.function.BiConsumer;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ItemPickerUserBinding;
+
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
+import static it.niedermann.nextcloud.deck.util.VCardUtil.getColorBasedOnDisplayName;
+
+public class ContactItemViewHolder extends RecyclerView.ViewHolder {
+
+    private final ItemPickerUserBinding binding;
+
+    public ContactItemViewHolder(@NonNull ItemPickerUserBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bind(@NonNull Uri uri, @Nullable Bitmap image, @NonNull String displayName, @Nullable String contactInformation, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect) {
+        itemView.setOnClickListener((v) -> onSelect.accept(uri, new Pair<>(displayName, image == null ? null : Glide.with(itemView.getContext()).load(image))));
+        binding.title.setText(displayName);
+        binding.contactInformation.setText(contactInformation);
+        if (image == null) {
+            binding.initials.setVisibility(VISIBLE);
+            binding.initials.setText(TextUtils.isEmpty(displayName)
+                    ? null
+                    : String.valueOf(displayName.charAt(0))
+            );
+            Glide.with(itemView.getContext())
+                    .load(new ColorDrawable(getColorBasedOnDisplayName(itemView.getContext(), displayName)))
+                    .apply(RequestOptions.circleCropTransform())
+                    .into(binding.avatar);
+        } else {
+            binding.initials.setVisibility(GONE);
+            binding.initials.setText(null);
+            Glide.with(itemView.getContext())
+                    .load(image)
+                    .placeholder(R.drawable.ic_person_grey600_24dp)
+                    .apply(RequestOptions.circleCropTransform())
+                    .into(binding.avatar);
+        }
+    }
+
+    public void bindError() {
+        itemView.setOnClickListener(null);
+        Glide.with(itemView.getContext())
+                .load(R.drawable.ic_person_grey600_24dp)
+                .into(binding.avatar);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactNativeItemViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactNativeItemViewHolder.java
new file mode 100644
index 000000000..a1d7d5921
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/ContactNativeItemViewHolder.java
@@ -0,0 +1,23 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ItemPickerNativeBinding;
+
+public class ContactNativeItemViewHolder extends RecyclerView.ViewHolder {
+
+    private final ItemPickerNativeBinding binding;
+
+    public ContactNativeItemViewHolder(@NonNull ItemPickerNativeBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bind(@NonNull Runnable onOpenMajorPicker) {
+        binding.title.setText(R.string.show_all_contacts);
+        binding.subtitle.setText(R.string.contacts);
+        itemView.setOnClickListener((v) -> onOpenMajorPicker.run());
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapter.java
new file mode 100644
index 000000000..aa96a0e69
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapter.java
@@ -0,0 +1,85 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import android.content.ContentUris;
+import android.content.Context;
+import android.net.Uri;
+import android.os.Handler;
+import android.os.Looper;
+import android.provider.MediaStore;
+import android.util.Pair;
+import android.view.LayoutInflater;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.RequiresApi;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.bumptech.glide.RequestBuilder;
+
+import java.util.function.BiConsumer;
+
+import it.niedermann.nextcloud.deck.databinding.ItemAttachmentDefaultBinding;
+import it.niedermann.nextcloud.deck.databinding.ItemPickerNativeBinding;
+
+import static android.provider.MediaStore.Downloads.DATE_ADDED;
+import static android.provider.MediaStore.Downloads.DATE_MODIFIED;
+import static android.provider.MediaStore.Downloads.EXTERNAL_CONTENT_URI;
+import static android.provider.MediaStore.Downloads.MIME_TYPE;
+import static android.provider.MediaStore.Downloads.SIZE;
+import static android.provider.MediaStore.Downloads.TITLE;
+import static android.provider.MediaStore.Downloads._ID;
+import static java.util.Objects.requireNonNull;
+
+@RequiresApi(api = 29)
+public class FileAdapter extends AbstractCursorPickerAdapter<RecyclerView.ViewHolder> {
+
+    private final int displayNameColumnIndex;
+    private final int sizeColumnIndex;
+    private final int modifiedColumnIndex;
+    private final int mimeTypeColumnIndex;
+
+    private FileAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable onSelectPicker) {
+        super(context, onSelect, onSelectPicker, _ID, requireNonNull(context.getContentResolver().query(EXTERNAL_CONTENT_URI, new String[]{_ID, TITLE, SIZE, DATE_MODIFIED, MIME_TYPE}, null, null, DATE_ADDED + " DESC")));
+        displayNameColumnIndex = cursor.getColumnIndex(TITLE);
+        sizeColumnIndex = cursor.getColumnIndex(SIZE);
+        modifiedColumnIndex = cursor.getColumnIndex(DATE_MODIFIED);
+        mimeTypeColumnIndex = cursor.getColumnIndex(MIME_TYPE);
+        notifyItemRangeInserted(0, getItemCount() + 1);
+    }
+
+    @NonNull
+    @Override
+    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        switch (viewType) {
+            case VIEW_TYPE_ITEM_NATIVE:
+                return new FileNativeItemViewHolder(ItemPickerNativeBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+            case VIEW_TYPE_ITEM:
+                return new FileItemViewHolder(ItemAttachmentDefaultBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+            default:
+                throw new IllegalStateException("Unknown viewType " + viewType);
+        }
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
+        switch (getItemViewType(position)) {
+            case VIEW_TYPE_ITEM_NATIVE: {
+                ((FileNativeItemViewHolder) holder).bind(openNativePicker);
+                break;
+            }
+            case VIEW_TYPE_ITEM: {
+                if (!cursor.isClosed()) {
+                    bindExecutor.execute(() -> {
+                        final long id = getItemId(position);
+                        final String name = cursor.getString(displayNameColumnIndex);
+                        final String mimeType = cursor.getString(mimeTypeColumnIndex);
+                        final long size = cursor.getLong(sizeColumnIndex);
+                        final long modified = cursor.getLong(modifiedColumnIndex);
+                        new Handler(Looper.getMainLooper()).post(() -> ((FileItemViewHolder) holder).bind(ContentUris.withAppendedId(MediaStore.Files.getContentUri("external"), id), name, mimeType, size, modified, onSelect));
+                    });
+                }
+                break;
+            }
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapterLegacy.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapterLegacy.java
new file mode 100644
index 000000000..1ac14361a
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileAdapterLegacy.java
@@ -0,0 +1,88 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import android.net.Uri;
+import android.os.Environment;
+import android.util.Pair;
+import android.view.LayoutInflater;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.bumptech.glide.RequestBuilder;
+
+import java.io.File;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.BiConsumer;
+
+import it.niedermann.nextcloud.deck.databinding.ItemAttachmentDefaultBinding;
+import it.niedermann.nextcloud.deck.databinding.ItemPickerNativeBinding;
+import it.niedermann.nextcloud.deck.util.AttachmentUtil;
+
+import static java.util.Collections.reverseOrder;
+import static java.util.Comparator.comparingLong;
+import static java.util.Objects.requireNonNull;
+import static java.util.stream.Collectors.toList;
+
+@Deprecated
+public class FileAdapterLegacy extends AbstractPickerAdapter<RecyclerView.ViewHolder> {
+
+    @NonNull
+    private final List<File> files;
+    @NonNull
+    protected final BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect;
+    @NonNull
+    protected final Runnable openNativePicker;
+
+    public FileAdapterLegacy(@NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker) {
+        // TODO run in separate thread?
+        this.onSelect = onSelect;
+        this.openNativePicker = openNativePicker;
+        this.files = Arrays.stream(requireNonNull(requireNonNull(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)).listFiles()))
+                .sorted(reverseOrder(comparingLong(File::lastModified)))
+                .collect(toList());
+
+    }
+
+    @NonNull
+    @Override
+    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        switch (viewType) {
+            case VIEW_TYPE_ITEM_NATIVE:
+                return new FileNativeItemViewHolder(ItemPickerNativeBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+            case VIEW_TYPE_ITEM:
+                return new FileItemViewHolder(ItemAttachmentDefaultBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+            default:
+                throw new IllegalStateException("Unknown viewType " + viewType);
+        }
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
+        switch (getItemViewType(position)) {
+            case VIEW_TYPE_ITEM_NATIVE: {
+                ((FileNativeItemViewHolder) holder).bind(openNativePicker);
+                break;
+            }
+            case VIEW_TYPE_ITEM: {
+                final File file = files.get(position - 1);
+                if (file.isFile()) {
+                    ((FileItemViewHolder) holder).bind(Uri.fromFile(file), file.getName(), AttachmentUtil.getMimeType(file.getAbsolutePath()), file.length(), file.lastModified(), onSelect);
+                } else {
+                    ((FileItemViewHolder) holder).bindError();
+                }
+                break;
+            }
+        }
+    }
+
+    @Override
+    public int getItemCount() {
+        return files.size();
+    }
+
+    public void onDestroy() {
+        // Let GarbageCollection do this stuff...
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileItemViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileItemViewHolder.java
new file mode 100644
index 000000000..f7d64aca8
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileItemViewHolder.java
@@ -0,0 +1,45 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import android.net.Uri;
+import android.util.Pair;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.bumptech.glide.RequestBuilder;
+
+import java.util.function.BiConsumer;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ItemAttachmentDefaultBinding;
+
+import static android.text.format.Formatter.formatFileSize;
+import static it.niedermann.nextcloud.deck.util.AttachmentUtil.getIconForMimeType;
+import static it.niedermann.nextcloud.deck.util.DateUtil.getRelativeDateTimeString;
+
+public class FileItemViewHolder extends RecyclerView.ViewHolder {
+
+    private final ItemAttachmentDefaultBinding binding;
+
+    public FileItemViewHolder(@NonNull ItemAttachmentDefaultBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bind(@NonNull Uri uri, @NonNull String name, String mimeType, long size, long modified, @Nullable BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect) {
+        itemView.setOnClickListener(onSelect == null ? null : (v) -> onSelect.accept(uri, new Pair<>(name, null)));
+        binding.filename.setText(name);
+        binding.filesize.setText(formatFileSize(binding.filesize.getContext(), size));
+        binding.modified.setText(getRelativeDateTimeString(binding.modified.getContext(), modified));
+        binding.preview.setImageResource(getIconForMimeType(mimeType));
+    }
+
+    public void bindError() {
+        binding.filename.setText(R.string.simple_exception);
+        binding.filesize.setText(null);
+        binding.modified.setText(null);
+        itemView.setOnClickListener(null);
+        binding.preview.setImageResource(R.drawable.ic_attach_file_grey600_24dp);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileNativeItemViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileNativeItemViewHolder.java
new file mode 100644
index 000000000..79129f26a
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/FileNativeItemViewHolder.java
@@ -0,0 +1,23 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ItemPickerNativeBinding;
+
+public class FileNativeItemViewHolder extends RecyclerView.ViewHolder {
+
+    private final ItemPickerNativeBinding binding;
+
+    public FileNativeItemViewHolder(@NonNull ItemPickerNativeBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bind(Runnable onOpenMajorPicker) {
+        binding.title.setText(R.string.show_all_files);
+        binding.subtitle.setText(R.string.downloads);
+        itemView.setOnClickListener((v) -> onOpenMajorPicker.run());
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryAdapter.java
new file mode 100644
index 000000000..658eb1ee3
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryAdapter.java
@@ -0,0 +1,100 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import android.annotation.SuppressLint;
+import android.content.ContentUris;
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.net.Uri;
+import android.os.Handler;
+import android.os.Looper;
+import android.provider.MediaStore;
+import android.util.Pair;
+import android.util.Size;
+import android.view.LayoutInflater;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.bumptech.glide.RequestBuilder;
+
+import java.io.IOException;
+import java.util.function.BiConsumer;
+
+import it.niedermann.nextcloud.deck.databinding.ItemAttachmentImageBinding;
+import it.niedermann.nextcloud.deck.databinding.ItemPhotoPreviewBinding;
+
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.Build.VERSION_CODES.Q;
+import static android.provider.BaseColumns._ID;
+import static android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
+
+public class GalleryAdapter extends AbstractCursorPickerAdapter<RecyclerView.ViewHolder> {
+
+    @NonNull
+    private final LifecycleOwner lifecycleOwner;
+
+    @SuppressLint("InlinedApi")
+    private static final String sortOrder = (SDK_INT >= Q)
+            ? MediaStore.Images.Media.DATE_TAKEN
+            : MediaStore.Images.Media.DATE_ADDED;
+
+    public GalleryAdapter(@NonNull Context context, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect, @NonNull Runnable openNativePicker, @NonNull LifecycleOwner lifecycleOwner) {
+        super(context, onSelect, openNativePicker, EXTERNAL_CONTENT_URI, _ID, sortOrder + " DESC");
+        this.lifecycleOwner = lifecycleOwner;
+        notifyItemRangeInserted(0, getItemCount() + 1);
+    }
+
+    @NonNull
+    @Override
+    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        switch (viewType) {
+            case VIEW_TYPE_ITEM_NATIVE:
+                return new GalleryPhotoPreviewItemViewHolder(ItemPhotoPreviewBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+            case VIEW_TYPE_ITEM:
+                return new GalleryItemViewHolder(ItemAttachmentImageBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+            default:
+                throw new IllegalStateException("Unknown viewType " + viewType);
+        }
+
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
+        switch (getItemViewType(position)) {
+            case VIEW_TYPE_ITEM_NATIVE: {
+                ((GalleryPhotoPreviewItemViewHolder) holder).bind(openNativePicker, lifecycleOwner);
+                break;
+            }
+            case VIEW_TYPE_ITEM: {
+                final long id = getItemId(position);
+                bindExecutor.execute(() -> {
+                    try {
+                        final Bitmap thumbnail;
+                        if (SDK_INT >= Q) {
+                            thumbnail = contentResolver.loadThumbnail(ContentUris.withAppendedId(
+                                    EXTERNAL_CONTENT_URI, id), new Size(512, 384), null);
+                        } else {
+                            thumbnail = MediaStore.Images.Thumbnails.getThumbnail(
+                                    contentResolver, id,
+                                    MediaStore.Images.Thumbnails.MINI_KIND, null);
+                        }
+                        new Handler(Looper.getMainLooper()).post(() -> ((GalleryItemViewHolder) holder).bind(ContentUris.withAppendedId(
+                                EXTERNAL_CONTENT_URI, id), thumbnail, onSelect));
+                    } catch (IOException ignored) {
+                        new Handler(Looper.getMainLooper()).post(((GalleryItemViewHolder) holder)::bindError);
+                    }
+                });
+            }
+        }
+    }
+
+    @Override
+    public void onViewDetachedFromWindow(@NonNull RecyclerView.ViewHolder holder) {
+        super.onViewDetachedFromWindow(holder);
+        if (holder instanceof GalleryPhotoPreviewItemViewHolder) {
+            ((GalleryPhotoPreviewItemViewHolder) holder).unbind();
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemDecoration.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemDecoration.java
new file mode 100644
index 000000000..c70dc8277
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemDecoration.java
@@ -0,0 +1,29 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import android.graphics.Rect;
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Px;
+import androidx.recyclerview.widget.RecyclerView;
+
+public class GalleryItemDecoration extends RecyclerView.ItemDecoration {
+
+    @Px
+    private final int gutter;
+
+    public GalleryItemDecoration(@Px int gutter) {
+        this.gutter = gutter;
+    }
+
+    @Override
+    public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
+        final int position = parent.getChildAdapterPosition(view);
+        if (position >= 0) {
+            outRect.left = gutter;
+            outRect.top = gutter;
+            outRect.right = gutter;
+            outRect.bottom = gutter;
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemViewHolder.java
new file mode 100644
index 000000000..346fca9c3
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryItemViewHolder.java
@@ -0,0 +1,42 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import android.graphics.Bitmap;
+import android.net.Uri;
+import android.util.Pair;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.bumptech.glide.Glide;
+import com.bumptech.glide.RequestBuilder;
+
+import java.util.function.BiConsumer;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ItemAttachmentImageBinding;
+
+public class GalleryItemViewHolder extends RecyclerView.ViewHolder {
+
+    private final ItemAttachmentImageBinding binding;
+
+    public GalleryItemViewHolder(@NonNull ItemAttachmentImageBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bind(@NonNull Uri uri, @Nullable Bitmap image, @NonNull BiConsumer<Uri, Pair<String, RequestBuilder<?>>> onSelect) {
+        itemView.setOnClickListener((v) -> onSelect.accept(uri, new Pair<>(null, Glide.with(itemView.getContext()).load(image))));
+        Glide.with(itemView.getContext())
+                .load(image)
+                .placeholder(R.drawable.ic_image_grey600_24dp)
+                .into(binding.preview);
+    }
+
+    public void bindError() {
+        itemView.setOnClickListener(null);
+        Glide.with(itemView.getContext())
+                .load(R.drawable.ic_image_grey600_24dp)
+                .into(binding.preview);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryPhotoPreviewItemViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryPhotoPreviewItemViewHolder.java
new file mode 100644
index 000000000..00a833e57
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/picker/GalleryPhotoPreviewItemViewHolder.java
@@ -0,0 +1,51 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.picker;
+
+import androidx.annotation.NonNull;
+import androidx.camera.core.Preview;
+import androidx.camera.lifecycle.ProcessCameraProvider;
+import androidx.core.content.ContextCompat;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.google.common.util.concurrent.ListenableFuture;
+
+import java.util.concurrent.ExecutionException;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.databinding.ItemPhotoPreviewBinding;
+
+import static androidx.camera.core.CameraSelector.DEFAULT_BACK_CAMERA;
+
+public class GalleryPhotoPreviewItemViewHolder extends RecyclerView.ViewHolder {
+
+    private final ItemPhotoPreviewBinding binding;
+    private ProcessCameraProvider cameraProvider;
+
+    public GalleryPhotoPreviewItemViewHolder(@NonNull ItemPhotoPreviewBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bind(@NonNull Runnable openNativePicker, @NonNull LifecycleOwner lifecycleOwner) {
+        itemView.setOnClickListener((v) -> openNativePicker.run());
+        ListenableFuture<ProcessCameraProvider> cameraProviderFuture = ProcessCameraProvider.getInstance(itemView.getContext());
+        cameraProviderFuture.addListener(() -> {
+            try {
+                unbind();
+                cameraProvider = cameraProviderFuture.get();
+                Preview previewUseCase = new Preview.Builder().build();
+                previewUseCase.setSurfaceProvider(binding.preview.getSurfaceProvider());
+                cameraProvider.bindToLifecycle(lifecycleOwner, DEFAULT_BACK_CAMERA, previewUseCase);
+            } catch (ExecutionException | InterruptedException | IllegalArgumentException e) {
+                DeckLog.logError(e);
+            }
+        }, ContextCompat.getMainExecutor(itemView.getContext()));
+    }
+
+
+    public void unbind() {
+        if (cameraProvider != null) {
+            cameraProvider.unbindAll();
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialog.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialog.java
new file mode 100644
index 000000000..8ebdf1b50
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialog.java
@@ -0,0 +1,102 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.previewdialog;
+
+import android.app.Dialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.graphics.Color;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.view.LayoutInflater;
+
+import androidx.annotation.NonNull;
+import androidx.fragment.app.DialogFragment;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.swiperefreshlayout.widget.CircularProgressDrawable;
+
+import com.bumptech.glide.RequestBuilder;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.DialogPreviewBinding;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedAlertDialogBuilder;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
+
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
+import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
+
+public class PreviewDialog extends BrandedDialogFragment {
+
+    private DialogPreviewBinding binding;
+    private PreviewDialogViewModel viewModel;
+    private LiveData<RequestBuilder<?>> imageBuilder$;
+    private LiveData<String> title$;
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        viewModel = new ViewModelProvider(requireActivity()).get(PreviewDialogViewModel.class);
+        binding = DialogPreviewBinding.inflate(LayoutInflater.from(requireContext()));
+
+        final Context context = requireContext();
+
+        this.imageBuilder$ = this.viewModel.getImageBuilder();
+        this.imageBuilder$.observe(requireActivity(), builder -> {
+            if (builder == null) {
+                binding.avatar.setVisibility(GONE);
+            } else {
+                final CircularProgressDrawable circularProgressDrawable = new CircularProgressDrawable(context);
+                circularProgressDrawable.setStrokeWidth(5f);
+                circularProgressDrawable.setCenterRadius(30f);
+                circularProgressDrawable.setColorSchemeColors(isDarkTheme(context) ? Color.LTGRAY : Color.DKGRAY);
+                circularProgressDrawable.start();
+                binding.avatar.setVisibility(VISIBLE);
+                binding.avatar.post(() -> builder
+                        .placeholder(circularProgressDrawable)
+                        .into(binding.avatar));
+            }
+        });
+        this.title$ = this.viewModel.getTitle();
+        this.title$.observe(requireActivity(), title -> {
+            if (TextUtils.isEmpty(title)) {
+                binding.title.setVisibility(GONE);
+            } else {
+                binding.title.setVisibility(VISIBLE);
+                binding.title.setText(title);
+            }
+        });
+
+        return new BrandedAlertDialogBuilder(requireContext())
+                .setPositiveButton(R.string.simple_attach, (d, w) -> {
+                    viewModel.setResult(true);
+                    dismiss();
+                })
+                .setNeutralButton(R.string.simple_close, (d, w) -> {
+                    viewModel.setResult(false);
+                    dismiss();
+                })
+                .setView(binding.getRoot())
+                .create();
+    }
+
+    @Override
+    public void onCancel(@NonNull DialogInterface dialog) {
+        viewModel.setResult(false);
+        super.onCancel(dialog);
+    }
+
+    @Override
+    public void applyBrand(int mainColor) {
+    }
+
+    @Override
+    public void onDestroy() {
+        this.imageBuilder$.removeObservers(requireActivity());
+        this.title$.removeObservers(requireActivity());
+        super.onDestroy();
+    }
+
+    public static DialogFragment newInstance() {
+        return new PreviewDialog();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialogViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialogViewModel.java
new file mode 100644
index 000000000..8ee8a0e08
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/previewdialog/PreviewDialogViewModel.java
@@ -0,0 +1,50 @@
+package it.niedermann.nextcloud.deck.ui.card.attachments.previewdialog;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+import androidx.lifecycle.ViewModel;
+
+import com.bumptech.glide.RequestBuilder;
+
+import static androidx.lifecycle.Transformations.distinctUntilChanged;
+
+public class PreviewDialogViewModel extends ViewModel {
+
+    @NonNull
+    private final MutableLiveData<String> title$ = new MutableLiveData<>();
+    @NonNull
+    private final MutableLiveData<RequestBuilder<?>> imageBuilder$ = new MutableLiveData<>();
+    private MutableLiveData<Boolean> result$ = new MutableLiveData<>();
+
+    /**
+     * Call this before observing {@link #getResult()} to prepare the {@link PreviewDialog}.
+     */
+    public void prepareDialog(@Nullable String title, @Nullable RequestBuilder<?> imageBuilder) {
+        this.result$ = new MutableLiveData<>();
+        this.title$.setValue(title);
+        this.imageBuilder$.setValue(imageBuilder);
+    }
+
+    /**
+     * This will be a new instance after each call of {@link #prepareDialog(String, RequestBuilder)}.
+     *
+     * @return {@link Boolean#TRUE} if a positive action has been submitted, {@link Boolean#FALSE} if the dialog has been canceled.
+     */
+    public LiveData<Boolean> getResult() {
+        return this.result$;
+    }
+
+    protected LiveData<String> getTitle() {
+        return distinctUntilChanged(this.title$);
+    }
+
+    protected LiveData<RequestBuilder<?>> getImageBuilder() {
+        return distinctUntilChanged(this.imageBuilder$);
+    }
+
+    protected void setResult(boolean submittedPositive) {
+        result$.setValue(submittedPositive);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsFragment.java
index e261c37a2..3fd536aa6 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsFragment.java
@@ -15,7 +15,7 @@ import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
 import androidx.lifecycle.ViewModelProvider;
 
-import java.util.Date;
+import java.time.Instant;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
@@ -23,12 +23,15 @@ import it.niedermann.nextcloud.deck.databinding.FragmentCardEditTabCommentsBindi
 import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.full.FullDeckComment;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedFragment;
 import it.niedermann.nextcloud.deck.ui.card.EditActivity;
 import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
+import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
+import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.applyBrandToEditText;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.applyBrandToFAB;
 import static it.niedermann.nextcloud.deck.util.ViewUtil.setupMentions;
@@ -38,7 +41,6 @@ public class CardCommentsFragment extends BrandedFragment implements CommentEdit
     private FragmentCardEditTabCommentsBinding binding;
     private EditCardViewModel mainViewModel;
     private CommentsViewModel commentsViewModel;
-    private SyncManager syncManager;
     private CardCommentsAdapter adapter;
 
     public static Fragment newInstance() {
@@ -68,7 +70,6 @@ public class CardCommentsFragment extends BrandedFragment implements CommentEdit
 
         commentsViewModel = new ViewModelProvider(this).get(CommentsViewModel.class);
 
-        syncManager = new SyncManager(requireActivity());
         adapter = new CardCommentsAdapter(requireContext(), mainViewModel.getAccount(), requireActivity().getMenuInflater(), this, this, getChildFragmentManager());
         binding.comments.setAdapter(adapter);
 
@@ -82,7 +83,7 @@ public class CardCommentsFragment extends BrandedFragment implements CommentEdit
                 setupMentions(mainViewModel.getAccount(), comment.getComment().getMentions(), binding.replyCommentText);
             }
         });
-        syncManager.getFullCommentsForLocalCardId(mainViewModel.getFullCard().getLocalId()).observe(getViewLifecycleOwner(),
+        commentsViewModel.getFullCommentsForLocalCardId(mainViewModel.getFullCard().getLocalId()).observe(getViewLifecycleOwner(),
                 (comments) -> {
                     if (comments != null && comments.size() > 0) {
                         binding.emptyContentView.setVisibility(GONE);
@@ -100,13 +101,13 @@ public class CardCommentsFragment extends BrandedFragment implements CommentEdit
                 if (!TextUtils.isEmpty(binding.message.getText().toString().trim())) {
                     binding.emptyContentView.setVisibility(GONE);
                     binding.comments.setVisibility(VISIBLE);
-                    final DeckComment comment = new DeckComment(binding.message.getText().toString().trim(), mainViewModel.getAccount().getUserName(), new Date());
+                    final DeckComment comment = new DeckComment(binding.message.getText().toString().trim(), mainViewModel.getAccount().getUserName(), Instant.now());
                     final FullDeckComment parent = commentsViewModel.getReplyToComment().getValue();
                     if (parent != null) {
                         comment.setParentId(parent.getId());
                         commentsViewModel.setReplyToComment(null);
                     }
-                    syncManager.addCommentToCard(mainViewModel.getAccount().getId(), mainViewModel.getFullCard().getLocalId(), comment);
+                    commentsViewModel.addCommentToCard(mainViewModel.getAccount().getId(), mainViewModel.getFullCard().getLocalId(), comment);
                 }
                 binding.message.setText(null);
             });
@@ -116,6 +117,7 @@ public class CardCommentsFragment extends BrandedFragment implements CommentEdit
                 }
                 return true;
             });
+            binding.message.addTextChangedListener(new CardCommentsMentionProposer(getViewLifecycleOwner(), mainViewModel.getAccount(), mainViewModel.getBoardId(), binding.message, binding.mentionProposerWrapper, binding.mentionProposer));
         } else {
             binding.addCommentLayout.setVisibility(GONE);
         }
@@ -133,12 +135,17 @@ public class CardCommentsFragment extends BrandedFragment implements CommentEdit
 
     @Override
     public void onCommentEdited(Long id, String comment) {
-        syncManager.updateComment(mainViewModel.getAccount().getId(), mainViewModel.getFullCard().getLocalId(), id, comment);
+        commentsViewModel.updateComment(mainViewModel.getAccount().getId(), mainViewModel.getFullCard().getLocalId(), id, comment);
     }
 
     @Override
     public void onCommentDeleted(Long localId) {
-        syncManager.deleteComment(mainViewModel.getAccount().getId(), mainViewModel.getFullCard().getLocalId(), localId);
+        final WrappedLiveData<Void> deleteLiveData = commentsViewModel.deleteComment(mainViewModel.getAccount().getId(), mainViewModel.getFullCard().getLocalId(), localId);
+        observeOnce(deleteLiveData, this, (next) -> {
+            if (deleteLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteLiveData.getError())) {
+                ExceptionDialogFragment.newInstance(deleteLiveData.getError(), mainViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
     }
 
     @Override
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsMentionProposer.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsMentionProposer.java
new file mode 100644
index 000000000..7ca7a6384
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsMentionProposer.java
@@ -0,0 +1,139 @@
+package it.niedermann.nextcloud.deck.ui.card.comments;
+
+import android.annotation.SuppressLint;
+import android.net.Uri;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.view.View;
+import android.widget.EditText;
+import android.widget.ImageView;
+import android.widget.LinearLayout;
+
+import androidx.annotation.NonNull;
+import androidx.core.util.Pair;
+import androidx.lifecycle.LifecycleOwner;
+
+import com.bumptech.glide.Glide;
+import com.bumptech.glide.request.RequestOptions;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import it.niedermann.android.util.DimensionUtil;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.ui.card.comments.util.CommentsUtil;
+
+import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
+
+public class CardCommentsMentionProposer implements TextWatcher {
+
+    private final int avatarSize;
+    @NonNull
+    private final SyncManager syncManager;
+    @NonNull
+    private final LinearLayout.LayoutParams layoutParams;
+    @NonNull
+    private final LifecycleOwner owner;
+    @NonNull
+    private final Account account;
+    private final long boardLocalId;
+    @NonNull
+    private final EditText editText;
+    @NonNull
+    private final LinearLayout mentionProposer;
+    @NonNull
+    private final LinearLayout mentionProposerWrapper;
+
+    @NonNull
+    private final List<User> users = new ArrayList<>();
+
+    public CardCommentsMentionProposer(@NonNull LifecycleOwner owner, @NonNull Account account, long boardLocalId, @NonNull EditText editText, LinearLayout mentionProposerWrapper, @NonNull LinearLayout avatarProposer) {
+        this.owner = owner;
+        this.account = account;
+        this.boardLocalId = boardLocalId;
+        this.editText = editText;
+        this.mentionProposerWrapper = mentionProposerWrapper;
+        this.mentionProposer = avatarProposer;
+        syncManager = new SyncManager(editText.getContext());
+        avatarSize = DimensionUtil.INSTANCE.dpToPx(mentionProposer.getContext(), R.dimen.avatar_size_small);
+        layoutParams = new LinearLayout.LayoutParams(avatarSize, avatarSize);
+        layoutParams.setMarginEnd(DimensionUtil.INSTANCE.dpToPx(mentionProposer.getContext(), R.dimen.spacer_1x));
+    }
+
+    @Override
+    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+
+    }
+
+    @Override
+    public void onTextChanged(CharSequence s, int start, int before, int count) {
+        final int selectionStart = editText.getSelectionStart();
+        final int selectionEnd = editText.getSelectionEnd();
+        final Pair<String, Integer> mentionProposal = CommentsUtil.getUserNameForMentionProposal(s.toString(), selectionStart);
+        if (mentionProposal == null || (mentionProposal.first != null && mentionProposal.first.length() == 0) || selectionStart != selectionEnd) {
+            mentionProposer.removeAllViews();
+            mentionProposerWrapper.setVisibility(View.GONE);
+            this.users.clear();
+        } else {
+            if (mentionProposal.first != null && mentionProposal.second != null) {
+                observeOnce(syncManager.searchUserByUidOrDisplayName(account.getId(), boardLocalId, -1L, mentionProposal.first), owner, (users) -> {
+                    if (!users.equals(this.users)) {
+                        mentionProposer.removeAllViews();
+                        if (users.size() > 0) {
+                            mentionProposerWrapper.setVisibility(View.VISIBLE);
+                            for (User user : users) {
+                                final ImageView avatar = new ImageView(mentionProposer.getContext());
+                                avatar.setLayoutParams(layoutParams);
+                                updateListenerOfView(avatar, s, mentionProposal, user);
+
+                                mentionProposer.addView(avatar);
+
+                                Glide.with(avatar.getContext())
+                                        .load(account.getUrl() + "/index.php/avatar/" + Uri.encode(user.getUid()) + "/" + avatarSize)
+                                        .placeholder(R.drawable.ic_person_grey600_24dp)
+                                        .error(R.drawable.ic_person_grey600_24dp)
+                                        .apply(RequestOptions.circleCropTransform())
+                                        .into(avatar);
+                            }
+                        } else {
+                            mentionProposerWrapper.setVisibility(View.GONE);
+                        }
+                        this.users.clear();
+                        this.users.addAll(users);
+                    } else {
+                        int i = 0;
+                        for (User user : users) {
+                            updateListenerOfView(mentionProposer.getChildAt(i), s, mentionProposal, user);
+                            i++;
+                        }
+                    }
+                });
+            } else {
+                this.users.clear();
+                mentionProposer.removeAllViews();
+                mentionProposerWrapper.setVisibility(View.GONE);
+            }
+        }
+    }
+
+    @SuppressLint("SetTextI18n")
+    private void updateListenerOfView(View avatar, CharSequence s, Pair<String, Integer> mentionProposal, User user) {
+        avatar.setOnClickListener((c) -> {
+            editText.setText(
+                    s.subSequence(0, mentionProposal.second) +
+                            user.getUid() +
+                            s.subSequence(mentionProposal.second + mentionProposal.first.length(), s.length())
+            );
+            editText.setSelection(mentionProposal.second + user.getUid().length());
+            mentionProposerWrapper.setVisibility(View.GONE);
+        });
+    }
+
+    @Override
+    public void afterTextChanged(Editable s) {
+
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CommentsViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CommentsViewModel.java
index f7fd247a9..dada94d5b 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CommentsViewModel.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CommentsViewModel.java
@@ -1,15 +1,30 @@
 package it.niedermann.nextcloud.deck.ui.card.comments;
 
+import android.app.Application;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
-import androidx.lifecycle.ViewModel;
 
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.ocs.comment.DeckComment;
 import it.niedermann.nextcloud.deck.model.ocs.comment.full.FullDeckComment;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 
 @SuppressWarnings("WeakerAccess")
-public class CommentsViewModel extends ViewModel {
+public class CommentsViewModel extends AndroidViewModel {
 
-    private MutableLiveData<FullDeckComment> replyToComment = new MutableLiveData<>();
+    private final SyncManager syncManager;
+
+    private final MutableLiveData<FullDeckComment> replyToComment = new MutableLiveData<>();
+
+    public CommentsViewModel(@NonNull Application application) {
+        super(application);
+        this.syncManager = new SyncManager(application);
+    }
 
     public void setReplyToComment(FullDeckComment replyToComment) {
         this.replyToComment.postValue(replyToComment);
@@ -18,4 +33,20 @@ public class CommentsViewModel extends ViewModel {
     public LiveData<FullDeckComment> getReplyToComment() {
         return this.replyToComment;
     }
+
+    public LiveData<List<FullDeckComment>> getFullCommentsForLocalCardId(long localCardId) {
+        return syncManager.getFullCommentsForLocalCardId(localCardId);
+    }
+
+    public void addCommentToCard(long accountId, long cardId, @NonNull DeckComment comment) {
+        syncManager.addCommentToCard(accountId, cardId, comment);
+    }
+
+    public void updateComment(long accountId, long localCardId, long localCommentId, String comment) {
+        syncManager.updateComment(accountId, localCardId, localCommentId, comment);
+    }
+
+    public WrappedLiveData<Void> deleteComment(long accountId, long localCardId, long localCommentId) {
+        return syncManager.deleteComment(accountId, localCardId, localCommentId);
+    }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/ItemCommentViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/ItemCommentViewHolder.java
index 086d799af..3e540c95e 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/ItemCommentViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/ItemCommentViewHolder.java
@@ -11,22 +11,25 @@ import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.fragment.app.FragmentManager;
 import androidx.recyclerview.widget.RecyclerView;
 
-import java.text.DateFormat;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.time.format.FormatStyle;
 
+import it.niedermann.android.util.ClipboardUtil;
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemCommentBinding;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 import it.niedermann.nextcloud.deck.model.ocs.comment.full.FullDeckComment;
 import it.niedermann.nextcloud.deck.util.DateUtil;
-import it.niedermann.nextcloud.deck.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.util.ViewUtil;
 
-import static it.niedermann.nextcloud.deck.util.ClipboardUtil.copyToClipboard;
 import static it.niedermann.nextcloud.deck.util.ViewUtil.setupMentions;
 
 public class ItemCommentViewHolder extends RecyclerView.ViewHolder {
-    private ItemCommentBinding binding;
+    private final ItemCommentBinding binding;
+    private final DateTimeFormatter dateFormatter = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM);
 
     @SuppressWarnings("WeakerAccess")
     public ItemCommentViewHolder(ItemCommentBinding binding) {
@@ -35,15 +38,15 @@ public class ItemCommentViewHolder extends RecyclerView.ViewHolder {
     }
 
     public void bind(@NonNull FullDeckComment comment, @NonNull Account account, @ColorInt int mainColor, @NonNull MenuInflater inflater, @NonNull CommentDeletedListener deletedListener, @NonNull CommentSelectAsReplyListener selectAsReplyListener, @NonNull FragmentManager fragmentManager) {
-        ViewUtil.addAvatar(binding.avatar, account.getUrl(), comment.getComment().getActorId(), DimensionUtil.dpToPx(binding.avatar.getContext(), R.dimen.icon_size_details), R.drawable.ic_person_grey600_24dp);
+        ViewUtil.addAvatar(binding.avatar, account.getUrl(), comment.getComment().getActorId(), DimensionUtil.INSTANCE.dpToPx(binding.avatar.getContext(), R.dimen.icon_size_details), R.drawable.ic_person_grey600_24dp);
         binding.message.setText(comment.getComment().getMessage());
         binding.actorDisplayName.setText(comment.getComment().getActorDisplayName());
-        binding.creationDateTime.setText(DateUtil.getRelativeDateTimeString(binding.creationDateTime.getContext(), comment.getComment().getCreationDateTime().getTime()));
+        binding.creationDateTime.setText(DateUtil.getRelativeDateTimeString(binding.creationDateTime.getContext(), comment.getComment().getCreationDateTime().toEpochMilli()));
         itemView.setOnClickListener(View::showContextMenu);
 
         itemView.setOnCreateContextMenuListener((menu, v, menuInfo) -> {
             inflater.inflate(R.menu.comment_menu, menu);
-            menu.findItem(android.R.id.copy).setOnMenuItemClickListener(item -> copyToClipboard(itemView.getContext(), comment.getComment().getMessage()));
+            menu.findItem(android.R.id.copy).setOnMenuItemClickListener(item -> ClipboardUtil.INSTANCE.copyToClipboard(itemView.getContext(), comment.getComment().getMessage()));
             final MenuItem replyMenuItem = menu.findItem(R.id.reply);
             if (comment.getStatusEnum() != DBStatus.LOCAL_EDITED && account.getServerDeckVersionAsObject().supportsCommentsReplys()) {
                 replyMenuItem.setOnMenuItemClickListener(item -> {
@@ -72,7 +75,7 @@ public class ItemCommentViewHolder extends RecyclerView.ViewHolder {
         DrawableCompat.setTint(binding.notSyncedYet.getDrawable(), mainColor);
         binding.notSyncedYet.setVisibility(DBStatus.LOCAL_EDITED.equals(comment.getStatusEnum()) ? View.VISIBLE : View.GONE);
 
-        TooltipCompat.setTooltipText(binding.creationDateTime, DateFormat.getDateTimeInstance().format(comment.getComment().getCreationDateTime()));
+        TooltipCompat.setTooltipText(binding.creationDateTime, comment.getComment().getCreationDateTime().atZone(ZoneId.systemDefault()).format(dateFormatter));
         setupMentions(account, comment.getComment().getMentions(), binding.message);
 
         if (comment.getParent() == null) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/util/CommentsUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/util/CommentsUtil.java
new file mode 100644
index 000000000..5251291c8
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/util/CommentsUtil.java
@@ -0,0 +1,48 @@
+package it.niedermann.nextcloud.deck.ui.card.comments.util;
+
+
+import androidx.core.util.Pair;
+
+public class CommentsUtil {
+
+    public static Pair<String, Integer> getUserNameForMentionProposal(String text, int cursorPosition) {
+        Pair result = null;
+
+        if (text != null) {
+            // find start of relevant substring
+            int cursor = cursorPosition;
+            if (cursor < 1) {
+                return null;
+            }
+            int start = 0;
+            while (cursor > 0) {
+                cursor--;
+                if (Character.isWhitespace(text.charAt(cursor))) {
+                    start = cursor + 1;
+                    break;
+                }
+            }
+            if (text.length()-1 < start || text.charAt(start) != '@') {
+                return null;
+            }
+
+            // find end of relevant substring
+            cursor = cursorPosition;
+            int textLength = text.length();
+            int end = textLength;
+            while (cursor < textLength) {
+                if (Character.isWhitespace(text.charAt(cursor))) {
+                    end = cursor;
+                    break;
+                }
+                cursor++;
+            }
+
+            start++;
+            result = Pair.create(text.substring(start, end), start);
+
+        }
+
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/AssigneeAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/AssigneeAdapter.java
new file mode 100644
index 000000000..aa8c3e8f6
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/AssigneeAdapter.java
@@ -0,0 +1,80 @@
+package it.niedermann.nextcloud.deck.ui.card.details;
+
+import android.content.Context;
+import android.view.LayoutInflater;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.core.util.Consumer;
+import androidx.recyclerview.widget.RecyclerView;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.databinding.ItemAssigneeBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.User;
+
+import static androidx.recyclerview.widget.RecyclerView.NO_ID;
+
+@SuppressWarnings("WeakerAccess")
+public class AssigneeAdapter extends RecyclerView.Adapter<AssigneeViewHolder> {
+
+    private final Account account;
+    @NonNull
+    private List<User> users = new ArrayList<>();
+    @NonNull
+    private final Consumer<User> userClickedListener;
+
+    AssigneeAdapter(
+            @NonNull Consumer<User> userClickedListener,
+            @NonNull Account account
+    ) {
+        super();
+        this.userClickedListener = userClickedListener;
+        this.account = account;
+        setHasStableIds(true);
+    }
+
+    @Override
+    public long getItemId(int position) {
+        Long id = users.get(position).getLocalId();
+        return id == null ? NO_ID : id;
+    }
+
+    @NonNull
+    @Override
+    public AssigneeViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        final Context context = parent.getContext();
+        return new AssigneeViewHolder(ItemAssigneeBinding.inflate(LayoutInflater.from(context)));
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull AssigneeViewHolder holder, int position) {
+        final User user = users.get(position);
+        holder.bind(account, user, userClickedListener);
+    }
+
+    @Override
+    public int getItemCount() {
+        return users.size();
+    }
+
+    public void setUsers(@NonNull List<User> users) {
+        this.users.clear();
+        this.users.addAll(users);
+        notifyDataSetChanged();
+    }
+
+    public void addUser(@NonNull User user) {
+        this.users.add(user);
+        notifyItemInserted(this.users.size());
+    }
+
+    public void removeUser(@NonNull User user) {
+        final int index = this.users.indexOf(user);
+        this.users.remove(user);
+        notifyItemRemoved(index);
+    }
+
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/AssigneeDecoration.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/AssigneeDecoration.java
new file mode 100644
index 000000000..096dcfa53
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/AssigneeDecoration.java
@@ -0,0 +1,28 @@
+package it.niedermann.nextcloud.deck.ui.card.details;
+
+import android.graphics.Rect;
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Px;
+import androidx.recyclerview.widget.RecyclerView;
+
+public class AssigneeDecoration extends RecyclerView.ItemDecoration {
+
+    private final int gutter;
+
+    public AssigneeDecoration(@Px int gutter) {
+        this.gutter = gutter;
+    }
+
+    @Override
+    public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
+        final int position = parent.getChildAdapterPosition(view);
+
+        if (position >= 0) {
+            // All columns get some spacing at the bottom and at the right side
+            outRect.right = gutter;
+            outRect.bottom = gutter;
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/AssigneeViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/AssigneeViewHolder.java
new file mode 100644
index 000000000..ddb1236b6
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/AssigneeViewHolder.java
@@ -0,0 +1,29 @@
+package it.niedermann.nextcloud.deck.ui.card.details;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.util.Consumer;
+import androidx.recyclerview.widget.RecyclerView;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ItemAssigneeBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.User;
+import it.niedermann.nextcloud.deck.util.ViewUtil;
+
+public class AssigneeViewHolder extends RecyclerView.ViewHolder {
+    private ItemAssigneeBinding binding;
+
+    @SuppressWarnings("WeakerAccess")
+    public AssigneeViewHolder(ItemAssigneeBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bind(@NonNull Account account, @NonNull User user, @Nullable Consumer<User> onClickListener) {
+        ViewUtil.addAvatar(binding.avatar, account.getUrl(), user.getUid(), R.drawable.ic_person_grey600_24dp);
+        if(onClickListener != null) {
+            itemView.setOnClickListener((v) -> onClickListener.accept(user));
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardDetailsFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardDetailsFragment.java
index 3182fffa2..2c697de08 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardDetailsFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardDetailsFragment.java
@@ -2,25 +2,25 @@ package it.niedermann.nextcloud.deck.ui.card.details;
 
 import android.content.Context;
 import android.content.res.ColorStateList;
-import android.graphics.Color;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.text.Editable;
+import android.text.TextUtils;
 import android.text.TextWatcher;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.ImageView;
 import android.widget.LinearLayout;
 
 import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
 import androidx.annotation.Px;
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.core.content.ContextCompat;
 import androidx.core.graphics.ColorUtils;
 import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.fragment.app.Fragment;
 import androidx.lifecycle.ViewModelProvider;
+import androidx.recyclerview.widget.GridLayoutManager;
 
 import com.google.android.material.chip.Chip;
 import com.google.android.material.snackbar.Snackbar;
@@ -31,18 +31,21 @@ import com.wdullaer.materialdatetimepicker.time.TimePickerDialog.OnTimeSetListen
 import com.yydcdut.markdown.MarkdownProcessor;
 import com.yydcdut.markdown.syntax.edit.EditFactory;
 
-import java.text.DateFormat;
-import java.text.SimpleDateFormat;
-import java.util.Calendar;
-import java.util.Date;
-import java.util.Locale;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.LocalTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.FormatStyle;
 
+import it.niedermann.android.util.ColorUtil;
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.FragmentCardEditTabDetailsBinding;
 import it.niedermann.nextcloud.deck.model.Label;
 import it.niedermann.nextcloud.deck.model.User;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedDatePickerDialog;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedFragment;
@@ -51,26 +54,23 @@ import it.niedermann.nextcloud.deck.ui.branding.BrandedTimePickerDialog;
 import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
 import it.niedermann.nextcloud.deck.ui.card.LabelAutoCompleteAdapter;
 import it.niedermann.nextcloud.deck.ui.card.UserAutoCompleteAdapter;
+import it.niedermann.nextcloud.deck.ui.card.assignee.CardAssigneeDialog;
+import it.niedermann.nextcloud.deck.ui.card.assignee.CardAssigneeListener;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
 import it.niedermann.nextcloud.deck.util.MarkDownUtil;
-import it.niedermann.nextcloud.deck.util.ViewUtil;
 
-import static android.text.format.DateFormat.getDateFormat;
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.applyBrandToEditText;
-import static it.niedermann.nextcloud.deck.util.DimensionUtil.dpToPx;
 
-public class CardDetailsFragment extends BrandedFragment implements OnDateSetListener, OnTimeSetListener {
+public class CardDetailsFragment extends BrandedFragment implements OnDateSetListener, OnTimeSetListener, CardAssigneeListener {
 
     private FragmentCardEditTabDetailsBinding binding;
     private EditCardViewModel viewModel;
-    private SyncManager syncManager;
-    private DateFormat dateFormat;
-    private DateFormat dueTime = new SimpleDateFormat("HH:mm", Locale.ROOT);
-    @Px
-    private int avatarSize;
-    private LinearLayout.LayoutParams avatarLayoutParams;
+    private AssigneeAdapter adapter;
+    private final DateTimeFormatter dateFormatter = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM);
+    private final DateTimeFormatter timeFormatter = DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT);
     private AppCompatActivity activity;
 
     @Override
@@ -92,8 +92,6 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
                              ViewGroup container,
                              Bundle savedInstanceState) {
         binding = FragmentCardEditTabDetailsBinding.inflate(inflater, container, false);
-        dateFormat = getDateFormat(activity);
-
         viewModel = new ViewModelProvider(activity).get(EditCardViewModel.class);
 
         // This might be a zombie fragment with an empty EditCardViewModel after Android killed the activity (but not the fragment instance
@@ -103,22 +101,20 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
             return binding.getRoot();
         }
 
-        syncManager = new SyncManager(requireContext());
-
-        avatarSize = dpToPx(requireContext(), R.dimen.avatar_size);
-        avatarLayoutParams = new LinearLayout.LayoutParams(avatarSize, avatarSize);
-        avatarLayoutParams.setMargins(0, 0, dpToPx(requireContext(), R.dimen.spacer_1x), 0);
+        @Px final int avatarSize = DimensionUtil.INSTANCE.dpToPx(requireContext(), R.dimen.avatar_size);
+        final LinearLayout.LayoutParams avatarLayoutParams = new LinearLayout.LayoutParams(avatarSize, avatarSize);
+        avatarLayoutParams.setMargins(0, 0, DimensionUtil.INSTANCE.dpToPx(requireContext(), R.dimen.spacer_1x), 0);
 
-        setupPeople();
+        setupAssignees();
         setupLabels();
         setupDueDate();
         setupDescription();
+        setupProjects();
         binding.description.setText(viewModel.getFullCard().getCard().getDescription());
 
         return binding.getRoot();
     }
 
-
     @Override
     public void onResume() {
         super.onResume();
@@ -173,49 +169,14 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
         }
     }
 
-    private TimePickerDialog createTimePickerDialogFromDate(
-            @Nullable OnTimeSetListener listener,
-            @Nullable Date date
-    ) {
-        int hourOfDay = 0;
-        int minutes = 0;
-
-        if (date != null) {
-            hourOfDay = date.getHours();
-            minutes = date.getMinutes();
-        }
-        return BrandedTimePickerDialog.newInstance(listener, hourOfDay, minutes, true);
-    }
-
-    private DatePickerDialog createDatePickerDialogFromDate(
-            @Nullable OnDateSetListener listener,
-            @Nullable Date date
-    ) {
-        int year;
-        int month;
-        int day;
-
-        Calendar cal = Calendar.getInstance();
-        if (date != null) {
-            cal.setTime(date);
-            year = cal.get(Calendar.YEAR);
-            month = cal.get(Calendar.MONTH);
-            day = cal.get(Calendar.DAY_OF_MONTH);
-        } else {
-            year = cal.get(Calendar.YEAR);
-            month = cal.get(Calendar.MONTH);
-            day = cal.get(Calendar.DAY_OF_MONTH);
-        }
-        return BrandedDatePickerDialog.newInstance(listener, year, month, day);
-    }
-
     private void setupDueDate() {
         if (this.viewModel.getFullCard().getCard().getDueDate() != null) {
-            binding.dueDateDate.setText(dateFormat.format(this.viewModel.getFullCard().getCard().getDueDate()));
-            binding.dueDateTime.setText(dueTime.format(this.viewModel.getFullCard().getCard().getDueDate()));
-            binding.clearDueDate.setVisibility(View.VISIBLE);
+            final ZonedDateTime dueDate = this.viewModel.getFullCard().getCard().getDueDate().atZone(ZoneId.systemDefault());
+            binding.dueDateDate.setText(dueDate == null ? null : dueDate.format(dateFormatter));
+            binding.dueDateTime.setText(dueDate == null ? null : dueDate.format(timeFormatter));
+            binding.clearDueDate.setVisibility(VISIBLE);
         } else {
-            binding.clearDueDate.setVisibility(View.GONE);
+            binding.clearDueDate.setVisibility(GONE);
             binding.dueDateDate.setText(null);
             binding.dueDateTime.setText(null);
         }
@@ -223,31 +184,37 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
         if (viewModel.canEdit()) {
 
             binding.dueDateDate.setOnClickListener(v -> {
-                if (viewModel.getFullCard() != null && viewModel.getFullCard().getCard() != null) {
-                    createDatePickerDialogFromDate(this, viewModel.getFullCard().getCard().getDueDate()).show(getChildFragmentManager(), BrandedDatePickerDialog.class.getCanonicalName());
+                final LocalDate date;
+                if (viewModel.getFullCard() != null && viewModel.getFullCard().getCard() != null && viewModel.getFullCard().getCard().getDueDate() != null) {
+                    date = viewModel.getFullCard().getCard().getDueDate().atZone(ZoneId.systemDefault()).toLocalDate();
                 } else {
-                    createDatePickerDialogFromDate(this, null).show(getChildFragmentManager(), BrandedDatePickerDialog.class.getCanonicalName());
+                    date = LocalDate.now();
                 }
+                BrandedDatePickerDialog.newInstance(this, date.getYear(), date.getMonthValue(), date.getDayOfMonth())
+                        .show(getChildFragmentManager(), BrandedDatePickerDialog.class.getCanonicalName());
             });
 
             binding.dueDateTime.setOnClickListener(v -> {
-                if (viewModel.getFullCard() != null && viewModel.getFullCard().getCard() != null) {
-                    createTimePickerDialogFromDate(this, viewModel.getFullCard().getCard().getDueDate()).show(getChildFragmentManager(), BrandedTimePickerDialog.class.getCanonicalName());
+                final LocalTime time;
+                if (viewModel.getFullCard() != null && viewModel.getFullCard().getCard() != null && viewModel.getFullCard().getCard().getDueDate() != null) {
+                    time = viewModel.getFullCard().getCard().getDueDate().atZone(ZoneId.systemDefault()).toLocalTime();
                 } else {
-                    createTimePickerDialogFromDate(this, null).show(getChildFragmentManager(), BrandedTimePickerDialog.class.getCanonicalName());
+                    time = LocalTime.now();
                 }
+                BrandedTimePickerDialog.newInstance(this, time.getHour(), time.getMinute(), true)
+                        .show(getChildFragmentManager(), BrandedTimePickerDialog.class.getCanonicalName());
             });
 
             binding.clearDueDate.setOnClickListener(v -> {
                 binding.dueDateDate.setText(null);
                 binding.dueDateTime.setText(null);
                 viewModel.getFullCard().getCard().setDueDate(null);
-                binding.clearDueDate.setVisibility(View.GONE);
+                binding.clearDueDate.setVisibility(GONE);
             });
         } else {
             binding.dueDateDate.setEnabled(false);
             binding.dueDateTime.setEnabled(false);
-            binding.clearDueDate.setVisibility(View.GONE);
+            binding.clearDueDate.setVisibility(GONE);
         }
     }
 
@@ -266,7 +233,7 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
                     newLabel.setBoardId(boardId);
                     newLabel.setTitle(((LabelAutoCompleteAdapter) binding.labels.getAdapter()).getLastFilterText());
                     newLabel.setLocalId(null);
-                    WrappedLiveData<Label> createLabelLiveData = syncManager.createLabel(accountId, newLabel, boardId);
+                    WrappedLiveData<Label> createLabelLiveData = viewModel.createLabel(accountId, newLabel, boardId);
                     observeOnce(createLabelLiveData, CardDetailsFragment.this, createdLabel -> {
                         if (createLabelLiveData.hasError()) {
                             DeckLog.logError(createLabelLiveData.getError());
@@ -277,14 +244,14 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
                             ((LabelAutoCompleteAdapter) binding.labels.getAdapter()).exclude(createdLabel);
                             viewModel.getFullCard().getLabels().add(createdLabel);
                             binding.labelsGroup.addView(createChipFromLabel(newLabel));
-                            binding.labelsGroup.setVisibility(View.VISIBLE);
+                            binding.labelsGroup.setVisibility(VISIBLE);
                         }
                     });
                 } else {
                     ((LabelAutoCompleteAdapter) binding.labels.getAdapter()).exclude(label);
                     viewModel.getFullCard().getLabels().add(label);
                     binding.labelsGroup.addView(createChipFromLabel(label));
-                    binding.labelsGroup.setVisibility(View.VISIBLE);
+                    binding.labelsGroup.setVisibility(VISIBLE);
                 }
 
                 binding.labels.setText("");
@@ -296,18 +263,17 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
             for (Label label : viewModel.getFullCard().getLabels()) {
                 binding.labelsGroup.addView(createChipFromLabel(label));
             }
-            binding.labelsGroup.setVisibility(View.VISIBLE);
+            binding.labelsGroup.setVisibility(VISIBLE);
         } else {
             binding.labelsGroup.setVisibility(View.INVISIBLE);
         }
     }
 
-
     private Chip createChipFromLabel(Label label) {
         final Chip chip = new Chip(activity);
         chip.setText(label.getTitle());
         if (viewModel.canEdit()) {
-            chip.setCloseIcon(getResources().getDrawable(R.drawable.ic_close_circle_grey600));
+            chip.setCloseIcon(ContextCompat.getDrawable(requireContext(), R.drawable.ic_close_circle_grey600));
             chip.setCloseIconVisible(true);
             chip.setOnCloseIconClickListener(v -> {
                 binding.labelsGroup.removeView(chip);
@@ -316,9 +282,9 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
             });
         }
         try {
-            final int labelColor = Color.parseColor("#" + label.getColor());
+            final int labelColor = label.getColor();
             chip.setChipBackgroundColor(ColorStateList.valueOf(labelColor));
-            final int color = ColorUtil.getForegroundColorForBackgroundColor(labelColor);
+            final int color = ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(labelColor);
             chip.setTextColor(color);
 
             if (chip.getCloseIcon() != null) {
@@ -331,7 +297,15 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
         return chip;
     }
 
-    private void setupPeople() {
+    private void setupAssignees() {
+        adapter = new AssigneeAdapter((user) -> CardAssigneeDialog.newInstance(user).show(getChildFragmentManager(), CardAssigneeDialog.class.getSimpleName()), viewModel.getAccount());
+        binding.assignees.setAdapter(adapter);
+        binding.assignees.post(() -> {
+            @Px final int gutter = DimensionUtil.INSTANCE.dpToPx(requireContext(), R.dimen.spacer_1x);
+            final int spanCount = (int) (float) binding.assignees.getWidth() / (DimensionUtil.INSTANCE.dpToPx(requireContext(), R.dimen.avatar_size) + gutter);
+            binding.assignees.setLayoutManager(new GridLayoutManager(getContext(), spanCount));
+            binding.assignees.addItemDecoration(new AssigneeDecoration(gutter));
+        });
         if (viewModel.canEdit()) {
             Long localCardId = viewModel.getFullCard().getCard().getLocalId();
             localCardId = localCardId == null ? -1 : localCardId;
@@ -340,81 +314,90 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
                 User user = (User) adapterView.getItemAtPosition(position);
                 viewModel.getFullCard().getAssignedUsers().add(user);
                 ((UserAutoCompleteAdapter) binding.people.getAdapter()).exclude(user);
-                addAvatar(viewModel.getAccount().getUrl(), user);
+                adapter.addUser(user);
                 binding.people.setText("");
             });
 
             if (this.viewModel.getFullCard().getAssignedUsers() != null) {
-                binding.peopleList.removeAllViews();
-                for (User user : this.viewModel.getFullCard().getAssignedUsers()) {
-                    addAvatar(viewModel.getAccount().getUrl(), user);
-                }
+                adapter.setUsers(this.viewModel.getFullCard().getAssignedUsers());
             }
         } else {
             binding.people.setEnabled(false);
         }
     }
 
-    private void addAvatar(String baseUrl, User user) {
-        ImageView avatar = new ImageView(activity);
-        avatar.setLayoutParams(avatarLayoutParams);
-        if (viewModel.canEdit()) {
-            avatar.setOnClickListener(v -> {
-                viewModel.getFullCard().getAssignedUsers().remove(user);
-                binding.peopleList.removeView(avatar);
-                ((UserAutoCompleteAdapter) binding.people.getAdapter()).include(user);
-                BrandedSnackbar.make(
-                        requireView(), getString(R.string.unassigned_user, user.getDisplayname()),
-                        Snackbar.LENGTH_LONG)
-                        .setAction(R.string.simple_undo, v1 -> {
-                            viewModel.getFullCard().getAssignedUsers().add(user);
-                            ((UserAutoCompleteAdapter) binding.people.getAdapter()).exclude(user);
-                            addAvatar(baseUrl, user);
-                        }).show();
-            });
-        }
-        binding.peopleList.addView(avatar);
-        avatar.requestLayout();
-        ViewUtil.addAvatar(avatar, baseUrl, user.getUid(), avatarSize, R.drawable.ic_person_grey600_24dp);
-    }
-
     @Override
-    public void onDateSet(com.wdullaer.materialdatetimepicker.date.DatePickerDialog view, int year, int monthOfYear, int dayOfMonth) {
-        Calendar c = Calendar.getInstance();
+    public void onDateSet(DatePickerDialog view, int year, int monthOfYear, int dayOfMonth) {
         int hourOfDay;
         int minute;
 
-        if (binding.dueDateTime.getText() != null && binding.dueDateTime.length() > 0) {
-            hourOfDay = this.viewModel.getFullCard().getCard().getDueDate().getHours();
-            minute = this.viewModel.getFullCard().getCard().getDueDate().getMinutes();
-        } else {
+        final CharSequence selectedTime = binding.dueDateTime.getText();
+        if (TextUtils.isEmpty(selectedTime)) {
             hourOfDay = 0;
             minute = 0;
+        } else {
+            final LocalTime oldTime = LocalTime.from(this.viewModel.getFullCard().getCard().getDueDate().atZone(ZoneId.systemDefault()));
+            hourOfDay = oldTime.getHour();
+            minute = oldTime.getMinute();
         }
 
-        c.set(year, monthOfYear, dayOfMonth, hourOfDay, minute);
-        this.viewModel.getFullCard().getCard().setDueDate(c.getTime());
-        binding.dueDateDate.setText(dateFormat.format(c.getTime()));
+        final ZonedDateTime newDateTime = ZonedDateTime.of(
+                LocalDate.of(year, monthOfYear + 1, dayOfMonth),
+                LocalTime.of(hourOfDay, minute),
+                ZoneId.systemDefault()
+        );
+        this.viewModel.getFullCard().getCard().setDueDate(newDateTime.toInstant());
+        binding.dueDateDate.setText(newDateTime.format(dateFormatter));
 
-        if (this.viewModel.getFullCard().getCard().getDueDate() == null || this.viewModel.getFullCard().getCard().getDueDate().getTime() == 0) {
-            binding.clearDueDate.setVisibility(View.GONE);
+        if (this.viewModel.getFullCard().getCard().getDueDate() == null || this.viewModel.getFullCard().getCard().getDueDate().toEpochMilli() == 0) {
+            binding.clearDueDate.setVisibility(GONE);
         } else {
-            binding.clearDueDate.setVisibility(View.VISIBLE);
+            binding.clearDueDate.setVisibility(VISIBLE);
         }
     }
 
     @Override
-    public void onTimeSet(com.wdullaer.materialdatetimepicker.time.TimePickerDialog view, int hourOfDay, int minute, int second) {
-        if (this.viewModel.getFullCard().getCard().getDueDate() == null) {
-            this.viewModel.getFullCard().getCard().setDueDate(new Date());
+    public void onTimeSet(TimePickerDialog view, int hourOfDay, int minute, int second) {
+        final Instant oldInstant = this.viewModel.getFullCard().getCard().getDueDate();
+        final ZonedDateTime oldDateTime = oldInstant == null ? ZonedDateTime.now() : oldInstant.atZone(ZoneId.systemDefault());
+        final ZonedDateTime newDateTime = oldDateTime.with(
+                LocalTime.of(hourOfDay, minute)
+        );
+
+        this.viewModel.getFullCard().getCard().setDueDate(newDateTime.toInstant());
+        binding.dueDateTime.setText(newDateTime.format(timeFormatter));
+        if (this.viewModel.getFullCard().getCard().getDueDate() == null || this.viewModel.getFullCard().getCard().getDueDate().toEpochMilli() == 0) {
+            binding.clearDueDate.setVisibility(GONE);
+        } else {
+            binding.clearDueDate.setVisibility(VISIBLE);
         }
-        this.viewModel.getFullCard().getCard().getDueDate().setHours(hourOfDay);
-        this.viewModel.getFullCard().getCard().getDueDate().setMinutes(minute);
-        binding.dueDateTime.setText(dueTime.format(this.viewModel.getFullCard().getCard().getDueDate().getTime()));
-        if (this.viewModel.getFullCard().getCard().getDueDate() == null || this.viewModel.getFullCard().getCard().getDueDate().getTime() == 0) {
-            binding.clearDueDate.setVisibility(View.GONE);
+    }
+
+    private void setupProjects() {
+        if (viewModel.getFullCard().getProjects().size() > 0) {
+            binding.projectsTitle.setVisibility(VISIBLE);
+            binding.projects.setNestedScrollingEnabled(false);
+            final CardProjectsAdapter adapter = new CardProjectsAdapter(viewModel.getFullCard().getProjects(), getChildFragmentManager());
+            binding.projects.setAdapter(adapter);
+            binding.projects.setVisibility(VISIBLE);
         } else {
-            binding.clearDueDate.setVisibility(View.VISIBLE);
+            binding.projectsTitle.setVisibility(GONE);
+            binding.projects.setVisibility(GONE);
         }
     }
+
+    @Override
+    public void onUnassignUser(@NonNull User user) {
+        viewModel.getFullCard().getAssignedUsers().remove(user);
+        adapter.removeUser(user);
+        ((UserAutoCompleteAdapter) binding.people.getAdapter()).include(user);
+        BrandedSnackbar.make(
+                requireView(), getString(R.string.unassigned_user, user.getDisplayname()),
+                Snackbar.LENGTH_LONG)
+                .setAction(R.string.simple_undo, v1 -> {
+                    viewModel.getFullCard().getAssignedUsers().add(user);
+                    ((UserAutoCompleteAdapter) binding.people.getAdapter()).exclude(user);
+                    adapter.addUser(user);
+                }).show();
+    }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardDetailsListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardDetailsListener.java
deleted file mode 100644
index 2efbab789..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardDetailsListener.java
+++ /dev/null
@@ -1,21 +0,0 @@
-package it.niedermann.nextcloud.deck.ui.card.details;
-
-import java.util.Date;
-
-import it.niedermann.nextcloud.deck.model.Label;
-import it.niedermann.nextcloud.deck.model.User;
-
-public interface CardDetailsListener {
-
-    void onDescriptionChanged(String toString);
-
-    void onDueDateChanged(Date dueDate);
-
-    void onUserAdded(User user);
-
-    void onUserRemoved(User user);
-
-    void onLabelRemoved(Label label);
-
-    void onLabelAdded(Label createdLabel);
-}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardProjectsAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardProjectsAdapter.java
new file mode 100644
index 000000000..0c2d63d74
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardProjectsAdapter.java
@@ -0,0 +1,52 @@
+package it.niedermann.nextcloud.deck.ui.card.details;
+
+import android.view.LayoutInflater;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.fragment.app.FragmentManager;
+import androidx.recyclerview.widget.RecyclerView;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.databinding.ItemProjectBinding;
+import it.niedermann.nextcloud.deck.model.ocs.projects.full.OcsProjectWithResources;
+import it.niedermann.nextcloud.deck.ui.card.projectresources.CardProjectResourcesDialog;
+
+public class CardProjectsAdapter extends RecyclerView.Adapter<CardProjectsViewHolder> {
+
+    @NonNull
+    private final List<OcsProjectWithResources> projects;
+    @NonNull
+    private final FragmentManager fragmentManager;
+
+    public CardProjectsAdapter(@NonNull List<OcsProjectWithResources> projects, @NonNull FragmentManager fragmentManager) {
+        this.projects = new ArrayList<>(projects.size());
+        this.projects.addAll(projects);
+        this.fragmentManager = fragmentManager;
+        setHasStableIds(true);
+    }
+
+    @Override
+    public long getItemId(int position) {
+        return projects.get(position).getLocalId();
+    }
+
+    @NonNull
+    @Override
+    public CardProjectsViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        return new CardProjectsViewHolder(ItemProjectBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull CardProjectsViewHolder holder, int position) {
+        final OcsProjectWithResources project = projects.get(position);
+        holder.bind(project, (v) -> CardProjectResourcesDialog.newInstance(project.getName(), project.getResources()).show(fragmentManager, CardProjectResourcesDialog.class.getSimpleName()));
+    }
+
+    @Override
+    public int getItemCount() {
+        return projects.size();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardProjectsViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardProjectsViewHolder.java
new file mode 100644
index 000000000..9c5494af7
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/details/CardProjectsViewHolder.java
@@ -0,0 +1,32 @@
+package it.niedermann.nextcloud.deck.ui.card.details;
+
+import android.view.View.OnClickListener;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.recyclerview.widget.RecyclerView;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ItemProjectBinding;
+import it.niedermann.nextcloud.deck.model.ocs.projects.full.OcsProjectWithResources;
+
+public class CardProjectsViewHolder extends RecyclerView.ViewHolder {
+
+    private ItemProjectBinding binding;
+
+    public CardProjectsViewHolder(@NonNull ItemProjectBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bind(@NonNull OcsProjectWithResources project, @Nullable OnClickListener onClickListener) {
+        binding.projectName.setText(project.getName());
+        final int resourcesCount = project.getResources().size();
+        binding.resourcesCount.setText(itemView.getContext().getResources().getQuantityString(R.plurals.resources_count, resourcesCount, resourcesCount));
+        if (resourcesCount > 0) {
+            binding.getRoot().setOnClickListener(onClickListener);
+        } else {
+            binding.getRoot().setOnClickListener(null);
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/projectresources/CardProjectResourceAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/projectresources/CardProjectResourceAdapter.java
new file mode 100644
index 000000000..4c95574c3
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/projectresources/CardProjectResourceAdapter.java
@@ -0,0 +1,54 @@
+package it.niedermann.nextcloud.deck.ui.card.projectresources;
+
+import android.view.LayoutInflater;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.recyclerview.widget.RecyclerView;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.databinding.ItemProjectResourceBinding;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
+
+public class CardProjectResourceAdapter extends RecyclerView.Adapter<CardProjectResourceViewHolder> {
+
+    @NonNull
+    private final EditCardViewModel viewModel;
+    @NonNull
+    private final List<OcsProjectResource> resources;
+    @NonNull
+    private final LifecycleOwner owner;
+
+    public CardProjectResourceAdapter(@NonNull EditCardViewModel viewModel, @NonNull List<OcsProjectResource> resources, @NonNull LifecycleOwner owner) {
+        this.viewModel = viewModel;
+        this.resources = new ArrayList<>(resources.size());
+        this.resources.addAll(resources);
+        this.owner = owner;
+        setHasStableIds(true);
+    }
+
+    @Override
+    public long getItemId(int position) {
+        return resources.get(position).getLocalId();
+    }
+
+    @NonNull
+    @Override
+    public CardProjectResourceViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        return new CardProjectResourceViewHolder(ItemProjectResourceBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull CardProjectResourceViewHolder holder, int position) {
+        holder.bind(viewModel, resources.get(position), owner);
+    }
+
+    @Override
+    public int getItemCount() {
+        return this.resources.size();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/projectresources/CardProjectResourceViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/projectresources/CardProjectResourceViewHolder.java
new file mode 100644
index 000000000..272945e45
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/projectresources/CardProjectResourceViewHolder.java
@@ -0,0 +1,110 @@
+package it.niedermann.nextcloud.deck.ui.card.projectresources;
+
+import android.content.Intent;
+import android.content.res.Resources;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.recyclerview.widget.RecyclerView;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ItemProjectResourceBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.ui.card.EditActivity;
+import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
+import it.niedermann.nextcloud.deck.util.ProjectUtil;
+
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
+import static it.niedermann.nextcloud.deck.util.ProjectUtil.getResourceUri;
+
+public class CardProjectResourceViewHolder extends RecyclerView.ViewHolder {
+    @NonNull
+    private final ItemProjectResourceBinding binding;
+
+    public CardProjectResourceViewHolder(@NonNull ItemProjectResourceBinding binding) {
+        super(binding.getRoot());
+        this.binding = binding;
+    }
+
+    public void bind(@NonNull EditCardViewModel viewModel, @NonNull OcsProjectResource resource, @NonNull LifecycleOwner owner) {
+        final Account account = viewModel.getAccount();
+        final Resources resources = itemView.getResources();
+        binding.name.setText(resource.getName());
+        final @Nullable String link = resource.getLink();
+        binding.type.setVisibility(VISIBLE);
+        if (resource.getType() != null) {
+            switch (resource.getType()) {
+                case "deck": {
+                    // TODO https://github.com/stefan-niedermann/nextcloud-deck/issues/671
+                    linkifyViewHolder(account, link);
+                    binding.type.setText(resources.getString(R.string.project_type_deck_board));
+                    binding.image.setImageResource(R.drawable.project_deck_36dp);
+                    break;
+                }
+                case "deck-card": {
+                    try {
+                        long[] ids = ProjectUtil.extractBoardIdAndCardIdFromUrl(link);
+                        if (ids.length == 2) {
+                            viewModel.getCardByRemoteID(account.getId(), ids[1]).observe(owner, (fullCard) -> {
+                                if (fullCard != null) {
+                                    viewModel.getBoardByRemoteId(account.getId(), ids[0]).observe(owner, (board) -> {
+                                        if (board != null) {
+                                            binding.getRoot().setOnClickListener((v) -> itemView.getContext().startActivity(EditActivity.createEditCardIntent(itemView.getContext(), account, board.getLocalId(), fullCard.getLocalId())));
+                                        } else {
+                                            linkifyViewHolder(account, link);
+                                        }
+                                    });
+                                } else {
+                                    linkifyViewHolder(account, link);
+                                }
+                            });
+                        } else {
+                            linkifyViewHolder(account, link);
+                        }
+                    } catch (IllegalArgumentException e) {
+                        DeckLog.logError(e);
+                        linkifyViewHolder(account, link);
+                    }
+                    binding.type.setText(resources.getString(R.string.project_type_deck_card));
+                    binding.image.setImageResource(R.drawable.project_deck_36dp);
+                    break;
+                }
+                case "file": {
+                    binding.type.setText(resources.getString(R.string.project_type_file));
+                    linkifyViewHolder(account, link);
+                    binding.image.setImageResource(R.drawable.project_file_36dp);
+                    break;
+                }
+                case "room": {
+                    binding.type.setText(resources.getString(R.string.project_type_room));
+                    linkifyViewHolder(account, link);
+                    binding.image.setImageResource(R.drawable.project_talk_36dp);
+                    break;
+                }
+                default: {
+                    DeckLog.info("Unknown resource type for " + resource.getName() + ": " + resource.getType());
+                    binding.type.setVisibility(GONE);
+                    linkifyViewHolder(account, link);
+                    break;
+                }
+            }
+        } else {
+            DeckLog.warn("Resource type for " + resource.getName() + " is null");
+            binding.type.setVisibility(GONE);
+        }
+    }
+
+    private void linkifyViewHolder(@NonNull Account account, @Nullable String link) {
+        if (link != null) {
+            try {
+                binding.getRoot().setOnClickListener((v) -> itemView.getContext().startActivity(new Intent(Intent.ACTION_VIEW).setData(getResourceUri(account, link))));
+            } catch (IllegalArgumentException e) {
+                DeckLog.logError(e);
+            }
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/projectresources/CardProjectResourcesDialog.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/projectresources/CardProjectResourcesDialog.java
new file mode 100644
index 000000000..46195b309
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/projectresources/CardProjectResourcesDialog.java
@@ -0,0 +1,83 @@
+package it.niedermann.nextcloud.deck.ui.card.projectresources;
+
+import android.app.Dialog;
+import android.content.Context;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.appcompat.app.AlertDialog;
+import androidx.fragment.app.DialogFragment;
+import androidx.lifecycle.ViewModelProvider;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.DialogProjectResourcesBinding;
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedAlertDialogBuilder;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
+import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
+
+public class CardProjectResourcesDialog extends BrandedDialogFragment {
+
+    private static final String KEY_RESOURCES = "resources";
+    private static final String KEY_PROJECT_NAME = "projectName";
+    private DialogProjectResourcesBinding binding;
+    private EditCardViewModel viewModel;
+
+    private String projectName;
+    @NonNull
+    private List<OcsProjectResource> resources = new ArrayList<>();
+
+    @Override
+    public void onAttach(@NonNull Context context) {
+        super.onAttach(context);
+        final Bundle args = requireArguments();
+        if (!args.containsKey(KEY_RESOURCES)) {
+            throw new IllegalArgumentException("Provide at least " + KEY_RESOURCES);
+        }
+        //noinspection unchecked
+        this.resources.addAll((ArrayList<OcsProjectResource>) Objects.requireNonNull(args.getSerializable(KEY_RESOURCES)));
+        this.projectName = args.getString(KEY_PROJECT_NAME);
+    }
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        binding = DialogProjectResourcesBinding.inflate(LayoutInflater.from(requireContext()));
+        viewModel = new ViewModelProvider(requireActivity()).get(EditCardViewModel.class);
+
+        AlertDialog.Builder dialogBuilder = new BrandedAlertDialogBuilder(requireContext());
+
+        return dialogBuilder
+                .setTitle(projectName)
+                .setView(binding.getRoot())
+                .setNeutralButton(R.string.simple_close, null)
+                .create();
+    }
+
+    @Override
+    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+        final CardProjectResourceAdapter adapter = new CardProjectResourceAdapter(viewModel, resources, requireActivity());
+        binding.getRoot().setAdapter(adapter);
+        super.onActivityCreated(savedInstanceState);
+    }
+
+    @Override
+    public void applyBrand(int mainColor) {
+
+    }
+
+    public static DialogFragment newInstance(@Nullable String projectName, @NonNull List<OcsProjectResource> resources) {
+        final DialogFragment fragment = new CardProjectResourcesDialog();
+        final Bundle args = new Bundle();
+        args.putString(KEY_PROJECT_NAME, projectName);
+        args.putSerializable(KEY_RESOURCES, new ArrayList<>(resources));
+        fragment.setArguments(args);
+        return fragment;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionActivity.java
index 9eef878c3..ac6335b90 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionActivity.java
@@ -8,13 +8,12 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AppCompatActivity;
 
-import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.android.util.ClipboardUtil;
+import it.niedermann.nextcloud.deck.BuildConfig;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ActivityExceptionBinding;
 import it.niedermann.nextcloud.deck.ui.exception.tips.TipsAdapter;
-import it.niedermann.nextcloud.deck.util.ExceptionUtil;
-
-import static it.niedermann.nextcloud.deck.util.ClipboardUtil.copyToClipboard;
+import it.niedermann.nextcloud.exception.ExceptionUtil;
 
 public class ExceptionActivity extends AppCompatActivity {
 
@@ -22,9 +21,12 @@ public class ExceptionActivity extends AppCompatActivity {
 
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
         final ActivityExceptionBinding binding = ActivityExceptionBinding.inflate(getLayoutInflater());
+
         setContentView(binding.getRoot());
-        super.onCreate(savedInstanceState);
+        setSupportActionBar(binding.toolbar);
 
         Throwable throwable = ((Throwable) getIntent().getSerializableExtra(KEY_THROWABLE));
 
@@ -32,23 +34,18 @@ public class ExceptionActivity extends AppCompatActivity {
             throwable = new Exception("Could not get exception");
         }
 
-        DeckLog.logError(throwable);
+        final TipsAdapter adapter = new TipsAdapter(this::startActivity);
+        final String debugInfo = "Full Crash:\n\n" + ExceptionUtil.INSTANCE.getDebugInfos(this, throwable, BuildConfig.FLAVOR);
 
-        setSupportActionBar(binding.toolbar);
+        binding.tips.setAdapter(adapter);
+        binding.tips.setNestedScrollingEnabled(false);
         binding.toolbar.setTitle(R.string.error);
         binding.message.setText(throwable.getMessage());
-
-        final String debugInfo = ExceptionUtil.getDebugInfos(this, throwable, null);
-
         binding.stacktrace.setText(debugInfo);
+        binding.copy.setOnClickListener((v) -> ClipboardUtil.INSTANCE.copyToClipboard(this, getString(R.string.simple_exception), "```\n" + debugInfo + "\n```"));
+        binding.close.setOnClickListener((v) -> finish());
 
-        final TipsAdapter adapter = new TipsAdapter(this::startActivity);
-        binding.tips.setAdapter(adapter);
-        binding.tips.setNestedScrollingEnabled(false);
         adapter.setThrowable(this, null, throwable);
-
-        binding.copy.setOnClickListener((v) -> copyToClipboard(this, getString(R.string.simple_exception), "```\n" + debugInfo + "\n```"));
-        binding.close.setOnClickListener((v) -> finish());
     }
 
     @NonNull
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionDialogFragment.java
index 6c0d0ba79..7a84ce0b6 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionDialogFragment.java
@@ -11,14 +11,14 @@ import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.app.AppCompatDialogFragment;
 import androidx.fragment.app.DialogFragment;
 
+import it.niedermann.android.util.ClipboardUtil;
+import it.niedermann.nextcloud.deck.BuildConfig;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.DialogExceptionBinding;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.ui.exception.tips.TipsAdapter;
-import it.niedermann.nextcloud.deck.util.ExceptionUtil;
-
-import static it.niedermann.nextcloud.deck.util.ClipboardUtil.copyToClipboard;
+import it.niedermann.nextcloud.exception.ExceptionUtil;
 
 public class ExceptionDialogFragment extends AppCompatDialogFragment {
 
@@ -52,7 +52,7 @@ public class ExceptionDialogFragment extends AppCompatDialogFragment {
 
         final TipsAdapter adapter = new TipsAdapter((actionIntent) -> requireActivity().startActivity(actionIntent));
 
-        final String debugInfos = ExceptionUtil.getDebugInfos(requireContext(), throwable, account);
+        final String debugInfos = ExceptionUtil.INSTANCE.getDebugInfos(requireContext(), throwable, BuildConfig.FLAVOR, account == null ? null : account.getServerDeckVersion());
 
         binding.tips.setAdapter(adapter);
         binding.stacktrace.setText(debugInfos);
@@ -65,7 +65,7 @@ public class ExceptionDialogFragment extends AppCompatDialogFragment {
                 .setView(binding.getRoot())
                 .setTitle(R.string.error_dialog_title)
                 .setPositiveButton(android.R.string.copy, (a, b) -> {
-                    copyToClipboard(requireContext(), getString(R.string.simple_exception), "```\n" + debugInfos + "\n```");
+                    ClipboardUtil.INSTANCE.copyToClipboard(requireContext(), getString(R.string.simple_exception), "```\n" + debugInfos + "\n```");
                     a.dismiss();
                 })
                 .setNegativeButton(R.string.simple_close, null)
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionHandler.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionHandler.java
index 8f0bfce33..c62b23e51 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionHandler.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/ExceptionHandler.java
@@ -2,21 +2,24 @@ package it.niedermann.nextcloud.deck.ui.exception;
 
 import android.app.Activity;
 
-import org.jetbrains.annotations.NotNull;
+import androidx.annotation.NonNull;
+
+import it.niedermann.nextcloud.deck.DeckLog;
 
 public class ExceptionHandler implements Thread.UncaughtExceptionHandler {
 
-    private Activity context;
+    @NonNull
+    private final Activity activity;
 
-    public ExceptionHandler(Activity context) {
-        super();
-        this.context = context;
+    public ExceptionHandler(@NonNull Activity activity) {
+        this.activity = activity;
     }
 
     @Override
-    public void uncaughtException(@NotNull Thread t, Throwable e) {
-        context.getApplicationContext().startActivity(ExceptionActivity.createIntent(context, e));
-        context.finish();
+    public void uncaughtException(@NonNull Thread t, @NonNull Throwable e) {
+        DeckLog.logError(e);
+        activity.getApplicationContext().startActivity(ExceptionActivity.createIntent(activity, e));
+        activity.finish();
         Runtime.getRuntime().exit(0);
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsAdapter.java
index a059b2956..6bfd82b13 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsAdapter.java
@@ -39,6 +39,10 @@ import static it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment.
 
 public class TipsAdapter extends RecyclerView.Adapter<TipsViewHolder> {
 
+    private static final Intent INTENT_APP_INFO = new Intent(ACTION_APPLICATION_DETAILS_SETTINGS)
+            .setData(Uri.parse("package:" + BuildConfig.APPLICATION_ID))
+            .putExtra(INTENT_EXTRA_BUTTON_TEXT, R.string.error_action_open_deck_info);
+
     @NonNull
     private Consumer<Intent> actionButtonClickedListener;
     @NonNull
@@ -68,11 +72,8 @@ public class TipsAdapter extends RecyclerView.Adapter<TipsViewHolder> {
     public void setThrowable(@NonNull Context context, @Nullable Account account, @NonNull Throwable throwable) {
         if (throwable instanceof TokenMismatchException) {
             add(R.string.error_dialog_tip_token_mismatch_retry);
-            add(R.string.error_dialog_tip_token_mismatch_clear_storage);
-            Intent intent = new Intent(ACTION_APPLICATION_DETAILS_SETTINGS)
-                    .setData(Uri.parse("package:" + BuildConfig.APPLICATION_ID))
-                    .putExtra(INTENT_EXTRA_BUTTON_TEXT, R.string.error_action_open_deck_info);
-            add(R.string.error_dialog_tip_clear_storage, intent);
+            add(R.string.error_dialog_tip_clear_storage_might_help);
+            add(R.string.error_dialog_tip_clear_storage, INTENT_APP_INFO);
         } else if (throwable instanceof NextcloudFilesAppNotSupportedException) {
             add(R.string.error_dialog_tip_files_outdated);
         } else if (throwable instanceof NextcloudApiNotRespondingException) {
@@ -122,6 +123,10 @@ public class TipsAdapter extends RecyclerView.Adapter<TipsViewHolder> {
                     } else {
                         add(R.string.error_dialog_version_not_parsable);
                     }
+                    add(R.string.error_dialog_account_might_not_be_authorized);
+                    break;
+                case UNKNOWN_ACCOUNT_USER_ID:
+                    add(R.string.error_dialog_user_not_found_in_database);
                     break;
                 case CAPABILITIES_NOT_PARSABLE:
                 default:
@@ -133,15 +138,15 @@ public class TipsAdapter extends RecyclerView.Adapter<TipsViewHolder> {
                         add(R.string.error_dialog_capabilities_not_parsable);
                     }
             }
+            // Files app might no longer be authenticated: https://github.com/stefan-niedermann/nextcloud-deck/issues/621#issuecomment-665533567
+            add(R.string.error_dialog_tip_clear_storage_might_help);
+            add(R.string.error_dialog_tip_clear_storage, INTENT_APP_INFO);
         } else if (throwable instanceof RuntimeException) {
             if (throwable.getMessage() != null && throwable.getMessage().contains("database")) {
                 Intent reportIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(context.getString(R.string.url_report_bug)))
                         .putExtra(INTENT_EXTRA_BUTTON_TEXT, R.string.error_action_report_issue);
                 add(R.string.error_dialog_tip_database_upgrade_failed, reportIntent);
-                Intent clearIntent = new Intent(ACTION_APPLICATION_DETAILS_SETTINGS)
-                        .setData(Uri.parse("package:" + BuildConfig.APPLICATION_ID))
-                        .putExtra(INTENT_EXTRA_BUTTON_TEXT, R.string.error_action_open_deck_info);
-                add(R.string.error_dialog_tip_clear_storage, clearIntent);
+                add(R.string.error_dialog_tip_clear_storage, INTENT_APP_INFO);
             }
         }
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterDialogFragment.java
index aa6f59d04..6aa03b811 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterDialogFragment.java
@@ -8,6 +8,7 @@ import android.os.Bundle;
 import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AlertDialog;
+import androidx.core.content.ContextCompat;
 import androidx.fragment.app.DialogFragment;
 import androidx.fragment.app.Fragment;
 import androidx.fragment.app.FragmentManager;
@@ -19,6 +20,7 @@ import androidx.viewpager2.widget.ViewPager2;
 
 import com.google.android.material.tabs.TabLayoutMediator;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.DialogFilterBinding;
 import it.niedermann.nextcloud.deck.model.enums.EDueType;
@@ -45,8 +47,9 @@ public class FilterDialogFragment extends BrandedDialogFragment {
     public Dialog onCreateDialog(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
-        indicator = getResources().getDrawable(R.drawable.circle_grey600_8dp);
-        indicator.setColorFilter(getResources().getColor(R.color.primary), PorterDuff.Mode.SRC_ATOP);
+        indicator = ContextCompat.getDrawable(requireContext(), R.drawable.circle_grey600_8dp);
+        assert indicator != null;
+        indicator.setColorFilter(getResources().getColor(R.color.defaultBrand), PorterDuff.Mode.SRC_ATOP);
 
         filterViewModel = new ViewModelProvider(requireActivity()).get(FilterViewModel.class);
 
@@ -61,10 +64,10 @@ public class FilterDialogFragment extends BrandedDialogFragment {
             filterInformationDraft.observe(this, (draft) -> {
                 switch (position) {
                     case 0:
-                        tab.setIcon(draft.getLabels().size() > 0 ? indicator : null);
+                        tab.setIcon(draft.getLabels().size() > 0 || draft.isNoAssignedLabel() ? indicator : null);
                         break;
                     case 1:
-                        tab.setIcon(draft.getUsers().size() > 0 ? indicator : null);
+                        tab.setIcon(draft.getUsers().size() > 0 || draft.isNoAssignedUser() ? indicator : null);
                         break;
                     case 2:
                         tab.setIcon(draft.getDueType() != EDueType.NO_FILTER ? indicator : null);
@@ -103,9 +106,10 @@ public class FilterDialogFragment extends BrandedDialogFragment {
 
     @Override
     public void applyBrand(int mainColor) {
-        @ColorInt int finalMainColor = getSecondaryForegroundColorDependingOnTheme(requireContext(), mainColor);
-        binding.tabLayout.setSelectedTabIndicatorColor(finalMainColor);
-        indicator.setColorFilter(finalMainColor, PorterDuff.Mode.SRC_ATOP);
+        @ColorInt final int finalMainColor = getSecondaryForegroundColorDependingOnTheme(binding.tabLayout.getContext(), mainColor);
+        final boolean contrastRatioIsSufficient = ColorUtil.INSTANCE.getContrastRatio(mainColor, ContextCompat.getColor(binding.tabLayout.getContext(), R.color.primary)) > 1.7d;
+        binding.tabLayout.setSelectedTabIndicatorColor(contrastRatioIsSufficient ? mainColor : finalMainColor);
+        indicator.setColorFilter(contrastRatioIsSufficient ? mainColor : finalMainColor, PorterDuff.Mode.SRC_ATOP);
     }
 
     private static class TabsPagerAdapter extends FragmentStateAdapter {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterLabelsAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterLabelsAdapter.java
index 096f0db9c..39fb791be 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterLabelsAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterLabelsAdapter.java
@@ -1,20 +1,21 @@
 package it.niedermann.nextcloud.deck.ui.filter;
 
 import android.content.res.ColorStateList;
-import android.graphics.Color;
 import android.view.LayoutInflater;
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
 import androidx.recyclerview.widget.RecyclerView;
 
 import java.util.ArrayList;
 import java.util.List;
 
+import it.niedermann.android.util.ColorUtil;
+import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemFilterLabelBinding;
 import it.niedermann.nextcloud.deck.model.Label;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
 
 @SuppressWarnings("WeakerAccess")
 public class FilterLabelsAdapter extends RecyclerView.Adapter<FilterLabelsAdapter.LabelViewHolder> {
@@ -23,11 +24,17 @@ public class FilterLabelsAdapter extends RecyclerView.Adapter<FilterLabelsAdapte
     @NonNull
     private final List<Label> selectedLabels = new ArrayList<>();
     @Nullable
+    private static final Label NOT_ASSIGNED = null;
+    @Nullable
     private final SelectionListener<Label> selectionListener;
 
-    public FilterLabelsAdapter(@NonNull List<Label> labels, @NonNull List<Label> selectedLabels, @Nullable SelectionListener<Label> selectionListener) {
+    public FilterLabelsAdapter(@NonNull List<Label> labels, @NonNull List<Label> selectedLabels, boolean noAssignedLabel, @Nullable SelectionListener<Label> selectionListener) {
         super();
+        this.labels.add(NOT_ASSIGNED);
         this.labels.addAll(labels);
+        if (noAssignedLabel) {
+            this.selectedLabels.add(NOT_ASSIGNED);
+        }
         this.selectedLabels.addAll(selectedLabels);
         this.selectionListener = selectionListener;
         setHasStableIds(true);
@@ -36,7 +43,8 @@ public class FilterLabelsAdapter extends RecyclerView.Adapter<FilterLabelsAdapte
 
     @Override
     public long getItemId(int position) {
-        return labels.get(position).getLocalId();
+        @Nullable final Label label = labels.get(position);
+        return label == null ? -1L : label.getLocalId();
     }
 
     @NonNull
@@ -47,7 +55,11 @@ public class FilterLabelsAdapter extends RecyclerView.Adapter<FilterLabelsAdapte
 
     @Override
     public void onBindViewHolder(@NonNull LabelViewHolder viewHolder, int position) {
-        viewHolder.bind(labels.get(position));
+        if (position == 0) {
+            viewHolder.bindNotAssigned();
+        } else {
+            viewHolder.bind(labels.get(position));
+        }
     }
 
     @Override
@@ -55,26 +67,36 @@ public class FilterLabelsAdapter extends RecyclerView.Adapter<FilterLabelsAdapte
         return labels.size();
     }
 
-    public List<Label> getSelected() {
-        return selectedLabels;
-    }
-
     class LabelViewHolder extends RecyclerView.ViewHolder {
         private ItemFilterLabelBinding binding;
 
         LabelViewHolder(@NonNull ItemFilterLabelBinding binding) {
             super(binding.getRoot());
             this.binding = binding;
+            this.binding.label.setClickable(false);
         }
 
         void bind(final Label label) {
             binding.label.setText(label.getTitle());
-            final int labelColor = Color.parseColor("#" + label.getColor());
+            final int labelColor = label.getColor();
             binding.label.setChipBackgroundColor(ColorStateList.valueOf(labelColor));
-            final int color = ColorUtil.getForegroundColorForBackgroundColor(labelColor);
+            final int color = ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(labelColor);
             binding.label.setTextColor(color);
             itemView.setSelected(selectedLabels.contains(label));
+            bindClickListener(label);
+        }
+
+        public void bindNotAssigned() {
+            binding.label.setText(itemView.getContext().getString(R.string.no_assigned_label));
+            binding.label.setTextColor(ColorStateList.valueOf(ContextCompat.getColor(itemView.getContext(), R.color.accent)));
+            binding.label.setChipIcon(ContextCompat.getDrawable(itemView.getContext(), R.drawable.ic_baseline_block_24));
+            binding.label.setChipBackgroundColor(ColorStateList.valueOf(ContextCompat.getColor(itemView.getContext(), R.color.primary)));
+            binding.label.setRippleColor(null);
+            itemView.setSelected(selectedLabels.contains(NOT_ASSIGNED));
+            bindClickListener(NOT_ASSIGNED);
+        }
 
+        private void bindClickListener(@Nullable Label label) {
             itemView.setOnClickListener(view -> {
                 if (selectedLabels.contains(label)) {
                     selectedLabels.remove(label);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterLabelsFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterLabelsFragment.java
index 357f93cf9..e7d693185 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterLabelsFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterLabelsFragment.java
@@ -12,7 +12,6 @@ import androidx.lifecycle.ViewModelProvider;
 
 import it.niedermann.nextcloud.deck.databinding.DialogFilterLabelsBinding;
 import it.niedermann.nextcloud.deck.model.Label;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 import it.niedermann.nextcloud.deck.ui.MainViewModel;
 
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
@@ -31,21 +30,33 @@ public class FilterLabelsFragment extends Fragment implements SelectionListener<
 
         filterViewModel = new ViewModelProvider(requireActivity()).get(FilterViewModel.class);
 
-        observeOnce(new SyncManager(requireContext()).findProposalsForLabelsToAssign(mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId()), requireActivity(), (labels) -> {
+        observeOnce(filterViewModel.findProposalsForLabelsToAssign(mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId()), requireActivity(), (labels) -> {
             binding.labels.setNestedScrollingEnabled(false);
-            binding.labels.setAdapter(new FilterLabelsAdapter(labels, requireNonNull(filterViewModel.getFilterInformationDraft().getValue()).getLabels(), this));
+            binding.labels.setAdapter(new FilterLabelsAdapter(
+                    labels,
+                    requireNonNull(filterViewModel.getFilterInformationDraft().getValue()).getLabels(),
+                    requireNonNull(filterViewModel.getFilterInformationDraft().getValue()).isNoAssignedLabel(),
+                    this));
         });
 
         return binding.getRoot();
     }
 
     @Override
-    public void onItemSelected(Label item) {
-        filterViewModel.addFilterInformationDraftLabel(item);
+    public void onItemSelected(@Nullable Label item) {
+        if (item == null) {
+            filterViewModel.setNotAssignedLabel(true);
+        } else {
+            filterViewModel.addFilterInformationDraftLabel(item);
+        }
     }
 
     @Override
-    public void onItemDeselected(Label item) {
-        filterViewModel.removeFilterInformationLabel(item);
+    public void onItemDeselected(@Nullable Label item) {
+        if (item == null) {
+            filterViewModel.setNotAssignedLabel(false);
+        } else {
+            filterViewModel.removeFilterInformationLabel(item);
+        }
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserAdapter.java
index b4ae8f679..4b75b985f 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserAdapter.java
@@ -8,6 +8,8 @@ import androidx.annotation.Nullable;
 import androidx.annotation.Px;
 import androidx.recyclerview.widget.RecyclerView;
 
+import com.bumptech.glide.Glide;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -23,6 +25,8 @@ public class FilterUserAdapter extends RecyclerView.Adapter<FilterUserAdapter.Us
     final int avatarSize;
     @NonNull
     private final Account account;
+    @Nullable
+    private static final User NOT_ASSIGNED = null;
     @NonNull
     private final List<User> users = new ArrayList<>();
     @NonNull
@@ -30,11 +34,15 @@ public class FilterUserAdapter extends RecyclerView.Adapter<FilterUserAdapter.Us
     @Nullable
     private final SelectionListener<User> selectionListener;
 
-    public FilterUserAdapter(@Px int avatarSize, @NonNull Account account, @NonNull List<User> users, @NonNull List<User> selectedUsers, @Nullable SelectionListener selectionListener) {
+    public FilterUserAdapter(@Px int avatarSize, @NonNull Account account, @NonNull List<User> users, @NonNull List<User> selectedUsers, boolean noAssignedUser, @Nullable SelectionListener<User> selectionListener) {
         super();
         this.avatarSize = avatarSize;
         this.account = account;
+        this.users.add(NOT_ASSIGNED);
         this.users.addAll(users);
+        if (noAssignedUser) {
+            this.selectedUsers.add(NOT_ASSIGNED);
+        }
         this.selectedUsers.addAll(selectedUsers);
         this.selectionListener = selectionListener;
         setHasStableIds(true);
@@ -43,7 +51,8 @@ public class FilterUserAdapter extends RecyclerView.Adapter<FilterUserAdapter.Us
 
     @Override
     public long getItemId(int position) {
-        return users.get(position).getLocalId();
+        @Nullable final User user = users.get(position);
+        return user == null ? -1L : user.getLocalId();
     }
 
     @NonNull
@@ -54,7 +63,11 @@ public class FilterUserAdapter extends RecyclerView.Adapter<FilterUserAdapter.Us
 
     @Override
     public void onBindViewHolder(@NonNull UserViewHolder viewHolder, int position) {
-        viewHolder.bind(users.get(position));
+        if (position == 0) {
+            viewHolder.bindNotAssigned();
+        } else {
+            viewHolder.bind(users.get(position));
+        }
     }
 
     @Override
@@ -62,10 +75,6 @@ public class FilterUserAdapter extends RecyclerView.Adapter<FilterUserAdapter.Us
         return users.size();
     }
 
-    public List<User> getSelected() {
-        return selectedUsers;
-    }
-
     class UserViewHolder extends RecyclerView.ViewHolder {
         private ItemFilterUserBinding binding;
 
@@ -74,22 +83,34 @@ public class FilterUserAdapter extends RecyclerView.Adapter<FilterUserAdapter.Us
             this.binding = binding;
         }
 
-        void bind(final User user) {
-            binding.displayName.setText(user.getDisplayname());
+        void bind(@NonNull final User user) {
+            binding.title.setText(user.getDisplayname());
             ViewUtil.addAvatar(binding.avatar, account.getUrl(), user.getUid(), avatarSize, R.drawable.ic_person_grey600_24dp);
             itemView.setSelected(selectedUsers.contains(user));
+            bindClickListener(user);
+        }
+
+        public void bindNotAssigned() {
+            binding.title.setText(itemView.getContext().getString(R.string.simple_unassigned));
+            Glide.with(itemView.getContext())
+                    .load(R.drawable.ic_baseline_block_24)
+                    .into(binding.avatar);
+            itemView.setSelected(selectedUsers.contains(NOT_ASSIGNED));
+            bindClickListener(NOT_ASSIGNED);
+        }
 
+        private void bindClickListener(@Nullable User user) {
             itemView.setOnClickListener(view -> {
                 if (selectedUsers.contains(user)) {
                     selectedUsers.remove(user);
                     itemView.setSelected(false);
-                    if(selectionListener != null) {
+                    if (selectionListener != null) {
                         selectionListener.onItemDeselected(user);
                     }
                 } else {
                     selectedUsers.add(user);
                     itemView.setSelected(true);
-                    if(selectionListener != null) {
+                    if (selectionListener != null) {
                         selectionListener.onItemSelected(user);
                     }
                 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserFragment.java
index 64bc1db1f..6ffaec6a6 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterUserFragment.java
@@ -10,14 +10,13 @@ import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
 import androidx.lifecycle.ViewModelProvider;
 
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.DialogFilterAssigneesBinding;
 import it.niedermann.nextcloud.deck.model.User;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 import it.niedermann.nextcloud.deck.ui.MainViewModel;
 
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
-import static it.niedermann.nextcloud.deck.util.DimensionUtil.dpToPx;
 import static java.util.Objects.requireNonNull;
 
 public class FilterUserFragment extends Fragment implements SelectionListener<User> {
@@ -33,21 +32,35 @@ public class FilterUserFragment extends Fragment implements SelectionListener<Us
 
         filterViewModel = new ViewModelProvider(requireActivity()).get(FilterViewModel.class);
 
-        observeOnce(new SyncManager(requireContext()).findProposalsForUsersToAssign(mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId()), requireActivity(), (users) -> {
+        observeOnce(filterViewModel.findProposalsForUsersToAssign(mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId()), requireActivity(), (users) -> {
             binding.users.setNestedScrollingEnabled(false);
-            binding.users.setAdapter(new FilterUserAdapter(dpToPx(requireContext(), R.dimen.avatar_size), mainViewModel.getCurrentAccount(), users, requireNonNull(filterViewModel.getFilterInformationDraft().getValue()).getUsers(), this));
+            binding.users.setAdapter(new FilterUserAdapter(
+                    DimensionUtil.INSTANCE.dpToPx(requireContext(), R.dimen.avatar_size),
+                    mainViewModel.getCurrentAccount(),
+                    users,
+                    requireNonNull(filterViewModel.getFilterInformationDraft().getValue()).getUsers(),
+                    requireNonNull(filterViewModel.getFilterInformationDraft().getValue()).isNoAssignedUser(),
+                    this));
         });
 
         return binding.getRoot();
     }
 
     @Override
-    public void onItemSelected(User item) {
-        filterViewModel.addFilterInformationUser(item);
+    public void onItemSelected(@Nullable User item) {
+        if (item == null) {
+            filterViewModel.setNotAssignedUser(true);
+        } else {
+            filterViewModel.addFilterInformationUser(item);
+        }
     }
 
     @Override
-    public void onItemDeselected(User item) {
-        filterViewModel.removeFilterInformationUser(item);
+    public void onItemDeselected(@Nullable User item) {
+        if (item == null) {
+            filterViewModel.setNotAssignedUser(false);
+        } else {
+            filterViewModel.removeFilterInformationUser(item);
+        }
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterViewModel.java
index cf8dc1754..c42a61ebd 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterViewModel.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/FilterViewModel.java
@@ -1,28 +1,40 @@
 package it.niedermann.nextcloud.deck.ui.filter;
 
+import android.app.Application;
+
 import androidx.annotation.IntRange;
 import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
-import androidx.lifecycle.ViewModel;
+
+import java.util.List;
 
 import it.niedermann.nextcloud.deck.model.Label;
 import it.niedermann.nextcloud.deck.model.User;
 import it.niedermann.nextcloud.deck.model.enums.EDueType;
 import it.niedermann.nextcloud.deck.model.internal.FilterInformation;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 
 import static it.niedermann.nextcloud.deck.model.internal.FilterInformation.hasActiveFilter;
 
 @SuppressWarnings("WeakerAccess")
-public class FilterViewModel extends ViewModel {
+public class FilterViewModel extends AndroidViewModel {
+
+    private final SyncManager syncManager;
 
     @IntRange(from = 0, to = 2)
     private int currentFilterTab = 0;
 
     @NonNull
-    private MutableLiveData<FilterInformation> filterInformationDraft = new MutableLiveData<>(new FilterInformation());
+    private final MutableLiveData<FilterInformation> filterInformationDraft = new MutableLiveData<>(new FilterInformation());
     @NonNull
-    private MutableLiveData<FilterInformation> filterInformation = new MutableLiveData<>();
+    private final MutableLiveData<FilterInformation> filterInformation = new MutableLiveData<>();
+
+    public FilterViewModel(@NonNull Application application) {
+        super(application);
+        this.syncManager = new SyncManager(application);
+    }
 
     public void publishFilterInformationDraft() {
         this.filterInformation.postValue(hasActiveFilter(filterInformationDraft.getValue()) ? filterInformationDraft.getValue() : null);
@@ -66,6 +78,18 @@ public class FilterViewModel extends ViewModel {
         this.filterInformationDraft.postValue(newDraft);
     }
 
+    public void setNotAssignedUser(boolean notAssignedUser) {
+        FilterInformation newDraft = new FilterInformation(filterInformationDraft.getValue());
+        newDraft.setNoAssignedUser(notAssignedUser);
+        this.filterInformationDraft.postValue(newDraft);
+    }
+
+    public void setNotAssignedLabel(boolean notAssignedLabel) {
+        FilterInformation newDraft = new FilterInformation(filterInformationDraft.getValue());
+        newDraft.setNoAssignedLabel(notAssignedLabel);
+        this.filterInformationDraft.postValue(newDraft);
+    }
+
     public void removeFilterInformationLabel(@NonNull Label label) {
         FilterInformation newDraft = new FilterInformation(filterInformationDraft.getValue());
         newDraft.removeLabel(label);
@@ -86,4 +110,12 @@ public class FilterViewModel extends ViewModel {
     public int getCurrentFilterTab() {
         return this.currentFilterTab;
     }
+
+    public LiveData<List<User>> findProposalsForUsersToAssign(final long accountId, long boardId) {
+        return syncManager.findProposalsForUsersToAssign(accountId, boardId, -1L, -1);
+    }
+
+    public LiveData<List<Label>> findProposalsForLabelsToAssign(final long accountId, final long boardId) {
+        return syncManager.findProposalsForLabelsToAssign(accountId, boardId, -1L);
+    }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/SelectionListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/SelectionListener.java
index d2635a860..3fad71773 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/SelectionListener.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/filter/SelectionListener.java
@@ -1,9 +1,11 @@
 package it.niedermann.nextcloud.deck.ui.filter;
 
+import androidx.annotation.Nullable;
+
 public interface SelectionListener<T> {
-    void onItemSelected(T item);
+    void onItemSelected(@Nullable T item);
 
-    default void onItemDeselected(T item) {
+    default void onItemDeselected(@Nullable T item) {
         // Deselecting is optional
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountViewHolder.java
index 4b43cbed6..0892eb437 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountViewHolder.java
@@ -11,14 +11,14 @@ import androidx.recyclerview.widget.RecyclerView;
 import com.bumptech.glide.Glide;
 import com.bumptech.glide.request.RequestOptions;
 
-import it.niedermann.android.glidesso.SingleSignOnUrl;
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemAccountChooseBinding;
 import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.sso.glide.SingleSignOnUrl;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
-import static it.niedermann.nextcloud.deck.util.DimensionUtil.dpToPx;
 
 public class ManageAccountViewHolder extends RecyclerView.ViewHolder {
 
@@ -33,7 +33,7 @@ public class ManageAccountViewHolder extends RecyclerView.ViewHolder {
         binding.accountName.setText(account.getUserName());
         binding.accountHost.setText(Uri.parse(account.getUrl()).getHost());
         Glide.with(itemView.getContext())
-                .load(new SingleSignOnUrl(account.getName(), account.getAvatarUrl(dpToPx(binding.accountItemAvatar.getContext(), R.dimen.avatar_size))))
+                .load(new SingleSignOnUrl(account.getName(), account.getAvatarUrl(DimensionUtil.INSTANCE.dpToPx(binding.accountItemAvatar.getContext(), R.dimen.avatar_size))))
                 .placeholder(R.drawable.ic_baseline_account_circle_24)
                 .error(R.drawable.ic_baseline_account_circle_24)
                 .apply(RequestOptions.circleCropTransform())
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountsActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountsActivity.java
index 9d273cdcb..8aa45e39a 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountsActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountsActivity.java
@@ -5,15 +5,12 @@ import android.util.Log;
 
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AppCompatActivity;
-
-import com.nextcloud.android.sso.helper.SingleAccountHelper;
+import androidx.lifecycle.ViewModelProvider;
 
 import it.niedermann.nextcloud.deck.databinding.ActivityManageAccountsBinding;
 import it.niedermann.nextcloud.deck.model.Account;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 
 import static it.niedermann.nextcloud.deck.DeckApplication.readCurrentAccountId;
-import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentAccountId;
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 
 public class ManageAccountsActivity extends AppCompatActivity {
@@ -21,44 +18,37 @@ public class ManageAccountsActivity extends AppCompatActivity {
     private static final String TAG = ManageAccountsActivity.class.getSimpleName();
 
     private ActivityManageAccountsBinding binding;
+    private ManageAccountsViewModel viewModel;
     private ManageAccountAdapter adapter;
-    private SyncManager syncManager = null;
 
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
         binding = ActivityManageAccountsBinding.inflate(getLayoutInflater());
-        setContentView(binding.getRoot());
+        viewModel = new ViewModelProvider(this).get(ManageAccountsViewModel.class);
 
+        setContentView(binding.getRoot());
         setSupportActionBar(binding.toolbar);
 
-        syncManager = new SyncManager(this);
-
-        adapter = new ManageAccountAdapter((account) -> {
-            SingleAccountHelper.setCurrentAccount(getApplicationContext(), account.getName());
-            syncManager = new SyncManager(this);
-            saveCurrentAccountId(this, account.getId());
-        }, (accountPair) -> {
+        adapter = new ManageAccountAdapter((account) -> viewModel.setNewAccount(account), (accountPair) -> {
             if (accountPair.first != null) {
-                syncManager.deleteAccount(accountPair.first.getId());
+                viewModel.deleteAccount(accountPair.first.getId());
             } else {
                 throw new IllegalArgumentException("Could not delete account because given account was null.");
             }
             Account newAccount = accountPair.second;
             if (newAccount != null) {
-                SingleAccountHelper.setCurrentAccount(getApplicationContext(), newAccount.getName());
-                saveCurrentAccountId(this, newAccount.getId());
-                syncManager = new SyncManager(this);
+                viewModel.setNewAccount(newAccount);
             } else {
                 Log.i(TAG, "Got delete account request, but new account is null. Maybe last account has been deleted?");
             }
         });
         binding.accounts.setAdapter(adapter);
 
-        observeOnce(syncManager.readAccount(readCurrentAccountId(this)), this, (account -> {
+        observeOnce(viewModel.readAccount(readCurrentAccountId(this)), this, (account -> {
             adapter.setCurrentAccount(account);
-            syncManager.readAccounts().observe(this, (localAccounts -> {
+            viewModel.readAccounts().observe(this, (localAccounts -> {
                 if (localAccounts.size() == 0) {
                     Log.i(TAG, "No accounts, finishing " + ManageAccountsActivity.class.getSimpleName());
                     setResult(AppCompatActivity.RESULT_FIRST_USER);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountsViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountsViewModel.java
new file mode 100644
index 000000000..66e9d3850
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/manageaccounts/ManageAccountsViewModel.java
@@ -0,0 +1,45 @@
+package it.niedermann.nextcloud.deck.ui.manageaccounts;
+
+import android.app.Application;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+
+import com.nextcloud.android.sso.helper.SingleAccountHelper;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+
+import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentAccountId;
+
+@SuppressWarnings("WeakerAccess")
+public class ManageAccountsViewModel extends AndroidViewModel {
+
+    private SyncManager syncManager;
+
+    public ManageAccountsViewModel(@NonNull Application application) {
+        super(application);
+        this.syncManager = new SyncManager(application);
+    }
+
+    public LiveData<Account> readAccount(long id) {
+        return syncManager.readAccount(id);
+    }
+
+    public LiveData<List<Account>> readAccounts() {
+        return syncManager.readAccounts();
+    }
+
+    public void setNewAccount(@NonNull Account account) {
+        SingleAccountHelper.setCurrentAccount(getApplication(), account.getName());
+        syncManager = new SyncManager(getApplication());
+        saveCurrentAccountId(getApplication(), account.getId());
+    }
+
+    public void deleteAccount(long id) {
+        syncManager.deleteAccount(id);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/movecard/MoveCardDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/movecard/MoveCardDialogFragment.java
new file mode 100644
index 000000000..2b7eb52fe
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/movecard/MoveCardDialogFragment.java
@@ -0,0 +1,128 @@
+package it.niedermann.nextcloud.deck.ui.movecard;
+
+import android.content.Context;
+import android.content.res.ColorStateList;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.DialogFragment;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.DialogMoveCardBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Board;
+import it.niedermann.nextcloud.deck.model.Stack;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
+import it.niedermann.nextcloud.deck.ui.branding.BrandingUtil;
+import it.niedermann.nextcloud.deck.ui.pickstack.PickStackFragment;
+import it.niedermann.nextcloud.deck.ui.pickstack.PickStackListener;
+import it.niedermann.nextcloud.deck.ui.pickstack.PickStackViewModel;
+
+import static android.view.View.GONE;
+import static android.view.View.VISIBLE;
+
+public class MoveCardDialogFragment extends BrandedDialogFragment implements PickStackListener {
+
+    private static final String KEY_ORIGIN_ACCOUNT_ID = "account_id";
+    private static final String KEY_ORIGIN_BOARD_LOCAL_ID = "board_local_id";
+    private static final String KEY_ORIGIN_CARD_TITLE = "card_title";
+    private static final String KEY_ORIGIN_CARD_LOCAL_ID = "card_local_id";
+    private Long originAccountId;
+    private Long originBoardLocalId;
+    private String originCardTitle;
+    private Long originCardLocalId;
+
+    private DialogMoveCardBinding binding;
+    private PickStackViewModel viewModel;
+    private MoveCardListener moveCardListener;
+
+    private Account selectedAccount;
+    private Board selectedBoard;
+    private Stack selectedStack;
+
+    @Override
+    public void onAttach(@NonNull Context context) {
+        super.onAttach(context);
+        if (getParentFragment() instanceof MoveCardListener) {
+            this.moveCardListener = (MoveCardListener) getParentFragment();
+        } else if (context instanceof MoveCardListener) {
+            this.moveCardListener = (MoveCardListener) context;
+        } else {
+            throw new IllegalArgumentException("Caller must implement " + MoveCardListener.class.getSimpleName());
+        }
+
+        final Bundle args = requireArguments();
+        originAccountId = args.getLong(KEY_ORIGIN_ACCOUNT_ID, -1L);
+        if (originAccountId < 0) {
+            throw new IllegalArgumentException("Missing " + KEY_ORIGIN_ACCOUNT_ID);
+        }
+        originCardLocalId = args.getLong(KEY_ORIGIN_CARD_LOCAL_ID, -1L);
+        if (originCardLocalId < 0) {
+            throw new IllegalArgumentException("Missing " + KEY_ORIGIN_CARD_LOCAL_ID);
+        }
+        originBoardLocalId = args.getLong(KEY_ORIGIN_BOARD_LOCAL_ID, -1L);
+        if (originBoardLocalId < 0) {
+            throw new IllegalArgumentException("Missing " + KEY_ORIGIN_BOARD_LOCAL_ID);
+        }
+        originCardTitle = args.getString(KEY_ORIGIN_CARD_TITLE);
+    }
+
+    @Nullable
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
+        binding = DialogMoveCardBinding.inflate(inflater);
+        binding.title.setText(getString(R.string.action_card_move_title, originCardTitle));
+        binding.submit.setOnClickListener((v) -> {
+            DeckLog.verbose("[Move card] Attempt to move to " + Stack.class.getSimpleName() + " #" + selectedStack.getLocalId());
+            this.moveCardListener.move(originAccountId, originCardLocalId, selectedAccount.getId(), selectedBoard.getLocalId(), selectedStack.getLocalId());
+            dismiss();
+        });
+        binding.cancel.setOnClickListener((v) -> dismiss());
+        return binding.getRoot();
+    }
+
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        getChildFragmentManager()
+                .beginTransaction()
+                .add(R.id.fragment_container, PickStackFragment.newInstance(false))
+                .commit();
+    }
+
+    @Override
+    public void onStackPicked(@NonNull Account account, @Nullable Board board, @Nullable Stack stack) {
+        this.selectedAccount = account;
+        this.selectedBoard = board;
+        this.selectedStack = stack;
+        if (board == null || stack == null) {
+            binding.submit.setEnabled(false);
+            binding.moveWarning.setVisibility(GONE);
+        } else {
+            binding.submit.setEnabled(true);
+            binding.moveWarning.setVisibility(board.getLocalId().equals(originBoardLocalId) ? GONE : VISIBLE);
+        }
+    }
+
+    @Override
+    public void applyBrand(int mainColor) {
+        final ColorStateList mainColorStateList = ColorStateList.valueOf(BrandingUtil.getSecondaryForegroundColorDependingOnTheme(requireContext(), mainColor));
+        binding.cancel.setTextColor(mainColorStateList);
+        binding.submit.setTextColor(mainColorStateList);
+    }
+
+    public static DialogFragment newInstance(long originAccountId, long originBoardLocalId, String originCardTitle, Long originCardLocalId) {
+        final DialogFragment dialogFragment = new MoveCardDialogFragment();
+        final Bundle args = new Bundle();
+        args.putLong(KEY_ORIGIN_ACCOUNT_ID, originAccountId);
+        args.putLong(KEY_ORIGIN_BOARD_LOCAL_ID, originBoardLocalId);
+        args.putString(KEY_ORIGIN_CARD_TITLE, originCardTitle);
+        args.putLong(KEY_ORIGIN_CARD_LOCAL_ID, originCardLocalId);
+        dialogFragment.setArguments(args);
+        return dialogFragment;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/movecard/MoveCardListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/movecard/MoveCardListener.java
new file mode 100644
index 000000000..f6f7a7a1f
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/movecard/MoveCardListener.java
@@ -0,0 +1,5 @@
+package it.niedermann.nextcloud.deck.ui.movecard;
+
+public interface MoveCardListener {
+    void move(long originAccountId, long originCardLocalId, long targetAccountId, long targetBoardLocalId, long targetStackLocalId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/pickstack/PickStackFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/pickstack/PickStackFragment.java
new file mode 100644
index 000000000..d65971cf4
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/pickstack/PickStackFragment.java
@@ -0,0 +1,204 @@
+package it.niedermann.nextcloud.deck.ui.pickstack;
+
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ArrayAdapter;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.Observer;
+import androidx.lifecycle.ViewModelProvider;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.databinding.FragmentPickStackBinding;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Board;
+import it.niedermann.nextcloud.deck.model.Stack;
+import it.niedermann.nextcloud.deck.ui.ImportAccountActivity;
+import it.niedermann.nextcloud.deck.ui.preparecreate.AccountAdapter;
+import it.niedermann.nextcloud.deck.ui.preparecreate.BoardAdapter;
+import it.niedermann.nextcloud.deck.ui.preparecreate.SelectedListener;
+import it.niedermann.nextcloud.deck.ui.preparecreate.StackAdapter;
+
+import static androidx.lifecycle.Transformations.switchMap;
+import static it.niedermann.nextcloud.deck.DeckApplication.readCurrentAccountId;
+import static it.niedermann.nextcloud.deck.DeckApplication.readCurrentBoardId;
+import static it.niedermann.nextcloud.deck.DeckApplication.readCurrentStackId;
+
+public class PickStackFragment extends Fragment {
+
+    private FragmentPickStackBinding binding;
+    private PickStackViewModel viewModel;
+
+    private static final String KEY_SHOW_BOARDS_WITHOUT_EDIT_PERMISSION = "show_boards_without_edit_permission";
+
+    private PickStackListener pickStackListener;
+
+    private boolean showBoardsWithoutEditPermission = false;
+    private long lastAccountId;
+    private long lastBoardId;
+    private long lastStackId;
+
+    private ArrayAdapter<Account> accountAdapter;
+    private ArrayAdapter<Board> boardAdapter;
+    private ArrayAdapter<Stack> stackAdapter;
+
+    @Nullable
+    private LiveData<List<Board>> boardsLiveData;
+    @NonNull
+    private Observer<List<Board>> boardsObserver = (boards) -> {
+        boardAdapter.clear();
+        boardAdapter.addAll(boards);
+        binding.boardSelect.setEnabled(true);
+
+        if (boards.size() > 0) {
+            binding.boardSelect.setEnabled(true);
+
+            Board boardToSelect = null;
+            for (Board board : boards) {
+                if (board.getLocalId() == lastBoardId) {
+                    boardToSelect = board;
+                    break;
+                }
+            }
+            if (boardToSelect == null) {
+                boardToSelect = boards.get(0);
+            }
+            binding.boardSelect.setSelection(boardAdapter.getPosition(boardToSelect));
+        } else {
+            binding.boardSelect.setEnabled(false);
+            pickStackListener.onStackPicked((Account) binding.accountSelect.getSelectedItem(), null, null);
+        }
+    };
+
+    @Nullable
+    private LiveData<List<Stack>> stacksLiveData;
+    @NonNull
+    private Observer<List<Stack>> stacksObserver = (stacks) -> {
+        stackAdapter.clear();
+        stackAdapter.addAll(stacks);
+
+        if (stacks.size() > 0) {
+            binding.stackSelect.setEnabled(true);
+
+            Stack stackToSelect = null;
+            for (Stack stack : stacks) {
+                if (stack.getLocalId() == lastStackId) {
+                    stackToSelect = stack;
+                    break;
+                }
+            }
+            if (stackToSelect == null) {
+                stackToSelect = stacks.get(0);
+            }
+            binding.stackSelect.setSelection(stackAdapter.getPosition(stackToSelect));
+        } else {
+            binding.stackSelect.setEnabled(false);
+            pickStackListener.onStackPicked((Account) binding.accountSelect.getSelectedItem(), (Board) binding.boardSelect.getSelectedItem(), null);
+        }
+    };
+
+    @Override
+    public void onAttach(@NonNull Context context) {
+        super.onAttach(context);
+        if (getParentFragment() instanceof PickStackListener) {
+            this.pickStackListener = (PickStackListener) getParentFragment();
+        } else if (context instanceof PickStackListener) {
+            this.pickStackListener = (PickStackListener) context;
+        } else {
+            throw new IllegalArgumentException("Caller must implement " + PickStackListener.class.getSimpleName());
+        }
+        final Bundle args = getArguments();
+        if (args != null) {
+            this.showBoardsWithoutEditPermission = args.getBoolean(KEY_SHOW_BOARDS_WITHOUT_EDIT_PERMISSION, false);
+        }
+    }
+
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        binding = FragmentPickStackBinding.inflate(getLayoutInflater());
+        viewModel = new ViewModelProvider(requireActivity()).get(PickStackViewModel.class);
+
+        accountAdapter = new AccountAdapter(requireContext());
+        binding.accountSelect.setAdapter(accountAdapter);
+        binding.accountSelect.setEnabled(false);
+        boardAdapter = new BoardAdapter(requireContext());
+        binding.boardSelect.setAdapter(boardAdapter);
+        binding.stackSelect.setEnabled(false);
+        stackAdapter = new StackAdapter(requireContext());
+        binding.stackSelect.setAdapter(stackAdapter);
+        binding.stackSelect.setEnabled(false);
+
+        switchMap(viewModel.hasAccounts(), hasAccounts -> {
+            if (hasAccounts) {
+                return viewModel.readAccounts();
+            } else {
+                startActivityForResult(new Intent(requireActivity(), ImportAccountActivity.class), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
+                return null;
+            }
+        }).observe(getViewLifecycleOwner(), (List<Account> accounts) -> {
+            if (accounts == null || accounts.size() == 0) {
+                throw new IllegalStateException("hasAccounts() returns true, but readAccounts() returns null or has no entry");
+            }
+
+            lastAccountId = readCurrentAccountId(requireContext());
+            lastBoardId = readCurrentBoardId(requireContext(), lastAccountId);
+            lastStackId = readCurrentStackId(requireContext(), lastAccountId, lastBoardId);
+
+            accountAdapter.clear();
+            accountAdapter.addAll(accounts);
+            binding.accountSelect.setEnabled(true);
+
+            for (Account account : accounts) {
+                if (account.getId() == lastAccountId) {
+                    binding.accountSelect.setSelection(accountAdapter.getPosition(account));
+                    break;
+                }
+            }
+        });
+
+        binding.accountSelect.setOnItemSelectedListener((SelectedListener) (parent, view, position, id) -> {
+            updateLiveDataSource(boardsLiveData, boardsObserver, showBoardsWithoutEditPermission
+                    ? viewModel.getBoards(parent.getSelectedItemId())
+                    : viewModel.getBoardsWithEditPermission(parent.getSelectedItemId()));
+        });
+
+        binding.boardSelect.setOnItemSelectedListener((SelectedListener) (parent, view, position, id) -> {
+            updateLiveDataSource(stacksLiveData, stacksObserver, viewModel.getStacksForBoard(binding.accountSelect.getSelectedItemId(), parent.getSelectedItemId()));
+        });
+
+        binding.stackSelect.setOnItemSelectedListener((SelectedListener) (parent, view, position, id) -> {
+            pickStackListener.onStackPicked((Account) binding.accountSelect.getSelectedItem(), (Board) binding.boardSelect.getSelectedItem(), (Stack) parent.getSelectedItem());
+        });
+
+        return binding.getRoot();
+    }
+
+    /**
+     * Updates the source of the given liveData and de- and reregisters the given observer.
+     */
+    private <T> void updateLiveDataSource(@Nullable LiveData<T> liveData, Observer<T> observer, LiveData<T> newSource) {
+        if (liveData != null) {
+            liveData.removeObserver(observer);
+        }
+        liveData = newSource;
+        liveData.observe(getViewLifecycleOwner(), observer);
+    }
+
+    public static PickStackFragment newInstance(boolean showBoardsWithoutEditPermission) {
+        final PickStackFragment fragment = new PickStackFragment();
+        final Bundle args = new Bundle();
+        args.putBoolean(KEY_SHOW_BOARDS_WITHOUT_EDIT_PERMISSION, showBoardsWithoutEditPermission);
+        fragment.setArguments(args);
+        return fragment;
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/pickstack/PickStackListener.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/pickstack/PickStackListener.java
new file mode 100644
index 000000000..ce227746a
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/pickstack/PickStackListener.java
@@ -0,0 +1,12 @@
+package it.niedermann.nextcloud.deck.ui.pickstack;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Board;
+import it.niedermann.nextcloud.deck.model.Stack;
+
+public interface PickStackListener {
+    void onStackPicked(@NonNull Account account, @Nullable Board board, @Nullable Stack stack);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/pickstack/PickStackViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/pickstack/PickStackViewModel.java
new file mode 100644
index 000000000..cc9fc2259
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/pickstack/PickStackViewModel.java
@@ -0,0 +1,45 @@
+package it.niedermann.nextcloud.deck.ui.pickstack;
+
+import android.app.Application;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.Board;
+import it.niedermann.nextcloud.deck.model.Stack;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+
+@SuppressWarnings("WeakerAccess")
+public class PickStackViewModel extends AndroidViewModel {
+
+    private final SyncManager syncManager;
+
+    public PickStackViewModel(@NonNull Application application) {
+        super(application);
+        this.syncManager = new SyncManager(application);
+    }
+
+    public LiveData<Boolean> hasAccounts() {
+        return syncManager.hasAccounts();
+    }
+
+    public LiveData<List<Account>> readAccounts() {
+        return syncManager.readAccounts();
+    }
+
+    public LiveData<List<Board>> getBoards(long accountId) {
+        return syncManager.getBoards(accountId);
+    }
+
+    public LiveData<List<Board>> getBoardsWithEditPermission(long accountId) {
+        return syncManager.getBoardsWithEditPermission(accountId);
+    }
+
+    public LiveData<List<Stack>> getStacksForBoard(long accountId, long localBoardId) {
+        return syncManager.getStacksForBoard(accountId, localBoardId);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/AccountAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/AccountAdapter.java
index 35a98efd7..f537c9fb4 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/AccountAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/AccountAdapter.java
@@ -6,14 +6,17 @@ import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
 
-import org.jetbrains.annotations.NotNull;
+import com.bumptech.glide.Glide;
+import com.bumptech.glide.request.RequestOptions;
 
+import java.net.URL;
+
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemPrepareCreateAccountBinding;
 import it.niedermann.nextcloud.deck.model.Account;
-import it.niedermann.nextcloud.deck.util.DimensionUtil;
-import it.niedermann.nextcloud.deck.util.ViewUtil;
+import it.niedermann.nextcloud.sso.glide.SingleSignOnUrl;
 
 public class AccountAdapter extends AbstractAdapter<Account> {
 
@@ -27,9 +30,9 @@ public class AccountAdapter extends AbstractAdapter<Account> {
         return item.getId();
     }
 
-    @NotNull
+    @NonNull
     @Override
-    public View getView(int position, View convertView, @NotNull ViewGroup parent) {
+    public View getView(int position, View convertView, @NonNull ViewGroup parent) {
         final ItemPrepareCreateAccountBinding binding;
         if (convertView == null) {
             binding = ItemPrepareCreateAccountBinding.inflate(inflater, parent, false);
@@ -40,8 +43,18 @@ public class AccountAdapter extends AbstractAdapter<Account> {
         final Account item = getItem(position);
         if (item != null) {
             binding.username.setText(item.getUserName());
-            binding.instance.setText(item.getUrl());
-            ViewUtil.addAvatar(binding.avatar, item.getUrl(), item.getUserName(), DimensionUtil.dpToPx(binding.avatar.getContext(), R.dimen.icon_size_details), R.drawable.ic_person_grey600_24dp);
+            try {
+                binding.instance.setText(new URL(item.getUrl()).getHost());
+            } catch (Throwable t) {
+                binding.instance.setText(item.getUrl());
+            }
+
+            Glide.with(getContext())
+                    .load(new SingleSignOnUrl(item.getName(), item.getAvatarUrl(DimensionUtil.INSTANCE.dpToPx(binding.avatar.getContext(), R.dimen.icon_size_details))))
+                    .placeholder(R.drawable.ic_baseline_account_circle_24)
+                    .error(R.drawable.ic_baseline_account_circle_24)
+                    .apply(RequestOptions.circleCropTransform())
+                    .into(binding.avatar);
         } else {
             DeckLog.logError(new IllegalArgumentException("No item for position " + position));
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/BoardAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/BoardAdapter.java
index 190c55e4b..c27fa04ee 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/BoardAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/BoardAdapter.java
@@ -6,8 +6,6 @@ import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
 
-import org.jetbrains.annotations.NotNull;
-
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemPrepareCreateBoardBinding;
@@ -26,9 +24,9 @@ public class BoardAdapter extends AbstractAdapter<Board> {
         return item.getLocalId();
     }
 
-    @NotNull
+    @NonNull
     @Override
-    public View getView(int position, View convertView, @NotNull ViewGroup parent) {
+    public View getView(int position, View convertView, @NonNull ViewGroup parent) {
         final ItemPrepareCreateBoardBinding binding;
         if (convertView == null) {
             binding = ItemPrepareCreateBoardBinding.inflate(inflater, parent, false);
@@ -39,7 +37,7 @@ public class BoardAdapter extends AbstractAdapter<Board> {
         final Board item = getItem(position);
         if (item != null) {
             binding.boardTitle.setText(item.getTitle());
-            binding.avatar.setImageDrawable(ViewUtil.getTintedImageView(binding.avatar.getContext(), R.drawable.circle_grey600_36dp, "#" + item.getColor()));
+            binding.avatar.setImageDrawable(ViewUtil.getTintedImageView(binding.avatar.getContext(), R.drawable.circle_grey600_36dp, item.getColor()));
         } else {
             DeckLog.logError(new IllegalArgumentException("No item for position " + position));
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/PrepareCreateActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/PrepareCreateActivity.java
index ab0cc4816..18317e078 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/PrepareCreateActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/PrepareCreateActivity.java
@@ -2,214 +2,52 @@ package it.niedermann.nextcloud.deck.ui.preparecreate;
 
 import android.content.ClipData;
 import android.content.Intent;
-import android.content.res.ColorStateList;
-import android.graphics.Color;
 import android.os.Bundle;
 import android.text.TextUtils;
-import android.widget.ArrayAdapter;
 
-import androidx.annotation.ColorInt;
-import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.appcompat.app.AppCompatActivity;
-import androidx.core.content.ContextCompat;
-import androidx.core.graphics.drawable.DrawableCompat;
-import androidx.lifecycle.LiveData;
-import androidx.lifecycle.Observer;
+import androidx.appcompat.app.ActionBar;
 
-import java.util.List;
-
-import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
-import it.niedermann.nextcloud.deck.databinding.ActivityPrepareCreateBinding;
 import it.niedermann.nextcloud.deck.model.Account;
-import it.niedermann.nextcloud.deck.model.Board;
-import it.niedermann.nextcloud.deck.model.full.FullStack;
-import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
-import it.niedermann.nextcloud.deck.ui.ImportAccountActivity;
-import it.niedermann.nextcloud.deck.ui.branding.Branded;
+import it.niedermann.nextcloud.deck.ui.PickStackActivity;
 import it.niedermann.nextcloud.deck.ui.card.EditActivity;
-import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
-import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
 
-import static android.graphics.Color.parseColor;
-import static androidx.lifecycle.Transformations.switchMap;
-import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
-import static it.niedermann.nextcloud.deck.DeckApplication.readCurrentAccountId;
-import static it.niedermann.nextcloud.deck.DeckApplication.readCurrentBoardId;
-import static it.niedermann.nextcloud.deck.DeckApplication.readCurrentStackId;
 import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentAccountId;
 import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentBoardId;
 import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentStackId;
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
-import static it.niedermann.nextcloud.deck.util.ColorUtil.contrastRatioIsSufficientBigAreas;
-
-public class PrepareCreateActivity extends AppCompatActivity implements Branded {
-
-    private ActivityPrepareCreateBinding binding;
-
-    private SyncManager syncManager;
-
-    private boolean brandingEnabled;
-
-    private long lastAccountId;
-    private long lastBoardId;
-    private long lastStackId;
 
-    private ArrayAdapter<Account> accountAdapter;
-    private ArrayAdapter<Board> boardAdapter;
-    private ArrayAdapter<FullStack> stackAdapter;
-
-    @Nullable
-    private LiveData<List<Board>> boardsLiveData;
-    @NonNull
-    private Observer<List<Board>> boardsObserver = (boards) -> {
-        boardAdapter.clear();
-        boardAdapter.addAll(boards);
-        binding.boardSelect.setEnabled(true);
-
-        if (boards.size() > 0) {
-            binding.boardSelect.setEnabled(true);
-
-            for (Board board : boards) {
-                if (board.getLocalId() == lastBoardId) {
-                    binding.boardSelect.setSelection(boardAdapter.getPosition(board));
-                    applyBrand(Color.parseColor('#' + board.getColor()));
-                    break;
-                }
-            }
-        } else {
-            applyBrand(ContextCompat.getColor(this, R.color.defaultBrand));
-            binding.boardSelect.setEnabled(false);
-            binding.submit.setEnabled(false);
-        }
-    };
-
-    @Nullable
-    private LiveData<List<FullStack>> stacksLiveData;
-    @NonNull
-    private Observer<List<FullStack>> stacksObserver = (fullStacks) -> {
-        stackAdapter.clear();
-        stackAdapter.addAll(fullStacks);
-
-        if (fullStacks.size() > 0) {
-            binding.stackSelect.setEnabled(true);
-            binding.submit.setEnabled(true);
-
-            for (FullStack fullStack : fullStacks) {
-                if (fullStack.getLocalId() == lastStackId) {
-                    binding.stackSelect.setSelection(stackAdapter.getPosition(fullStack));
-                    break;
-                }
-            }
-        } else {
-            binding.stackSelect.setEnabled(false);
-            binding.submit.setEnabled(false);
-        }
-    };
+public class PrepareCreateActivity extends PickStackActivity {
 
     @Override
-    protected void onCreate(Bundle savedInstanceState) {
+    public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-
-        Thread.setDefaultUncaughtExceptionHandler(new ExceptionHandler(this));
-
-        brandingEnabled = isBrandingEnabled(this);
-
-        binding = ActivityPrepareCreateBinding.inflate(getLayoutInflater());
-        setContentView(binding.getRoot());
-        setSupportActionBar(binding.toolbar);
-
-        accountAdapter = new AccountAdapter(this);
-        binding.accountSelect.setAdapter(accountAdapter);
-        binding.accountSelect.setEnabled(false);
-        boardAdapter = new BoardAdapter(this);
-        binding.boardSelect.setAdapter(boardAdapter);
-        binding.stackSelect.setEnabled(false);
-        stackAdapter = new StackAdapter(this);
-        binding.stackSelect.setAdapter(stackAdapter);
-        binding.stackSelect.setEnabled(false);
-
-        syncManager = new SyncManager(this);
-
-        switchMap(syncManager.hasAccounts(), hasAccounts -> {
-            if (hasAccounts) {
-                return syncManager.readAccounts();
-            } else {
-                startActivityForResult(new Intent(this, ImportAccountActivity.class), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
-                return null;
-            }
-        }).observe(this, (List<Account> accounts) -> {
-            if (accounts == null || accounts.size() == 0) {
-                throw new IllegalStateException("hasAccounts() returns true, but readAccounts() returns null or has no entry");
-            }
-
-            lastAccountId = readCurrentAccountId(this);
-            lastBoardId = readCurrentBoardId(this, lastAccountId);
-            lastStackId = readCurrentStackId(this, lastAccountId, lastBoardId);
-
-            accountAdapter.clear();
-            accountAdapter.addAll(accounts);
-            binding.accountSelect.setEnabled(true);
-
-            for (Account account : accounts) {
-                if (account.getId() == lastAccountId) {
-                    binding.accountSelect.setSelection(accountAdapter.getPosition(account));
-                    break;
-                }
-            }
-        });
-
-        binding.accountSelect.setOnItemSelectedListener((SelectedListener) (parent, view, position, id) -> {
-            updateLiveDataSource(boardsLiveData, boardsObserver, syncManager.getBoardsWithEditPermission(parent.getSelectedItemId()));
-        });
-
-        binding.boardSelect.setOnItemSelectedListener((SelectedListener) (parent, view, position, id) -> {
-            applyBrand(Color.parseColor('#' + ((Board) binding.boardSelect.getSelectedItem()).getColor()));
-            updateLiveDataSource(stacksLiveData, stacksObserver, syncManager.getStacksForBoard(binding.accountSelect.getSelectedItemId(), parent.getSelectedItemId()));
-        });
-
-        binding.cancel.setOnClickListener((v) -> finish());
-        binding.submit.setOnClickListener((v) -> onSubmit());
+        final ActionBar actionBar = getSupportActionBar();
+        if (actionBar != null) {
+            actionBar.setTitle(R.string.add_card);
+        }
     }
 
-    /**
-     * Updates the source of the given liveData and de- and reregisters the given observer.
-     */
-    private <T> void updateLiveDataSource(@Nullable LiveData<T> liveData, Observer<T> observer, LiveData<T> newSource) {
-        if (liveData != null) {
-            liveData.removeObserver(observer);
+    @Override
+    protected void onSubmit(Account account, long boardId, long stackId) {
+        final String receivedClipData = getReceivedClipData(getIntent());
+        if (receivedClipData == null) {
+            startActivity(EditActivity.createNewCardIntent(this, account, boardId, stackId));
+        } else {
+            startActivity(EditActivity.createNewCardIntent(this, account, boardId, stackId, receivedClipData));
         }
-        liveData = newSource;
-        liveData.observe(PrepareCreateActivity.this, observer);
-    }
 
-    /**
-     * Starts EditActivity and passes parameters.
-     */
-    private void onSubmit() {
-        final Account account = accountAdapter.getItem(binding.accountSelect.getSelectedItemPosition());
-        if (account != null) {
-            final long boardId = binding.boardSelect.getSelectedItemId();
-            final long stackId = binding.stackSelect.getSelectedItemId();
-            final String receivedClipData = getReceivedClipData(getIntent());
-            if (receivedClipData == null) {
-                startActivity(EditActivity.createNewCardIntent(this, account, boardId, stackId));
-            } else {
-                startActivity(EditActivity.createNewCardIntent(this, account, boardId, stackId, receivedClipData));
-            }
+        saveCurrentAccountId(this, account.getId());
+        saveCurrentBoardId(this, account.getId(), boardId);
+        saveCurrentStackId(this, account.getId(), boardId, stackId);
+        applyBrand(account.getColor());
 
-            saveCurrentAccountId(this, account.getId());
-            saveCurrentBoardId(this, account.getId(), boardId);
-            saveCurrentStackId(this, account.getId(), boardId, stackId);
-            applyBrand(parseColor(account.getColor()));
+        finish();
+    }
 
-            finish();
-        } else {
-            ExceptionDialogFragment.newInstance(new IllegalStateException("Selected account at position " + binding.accountSelect.getSelectedItemPosition() + " is null."), null).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
-        }
+    @Override
+    protected boolean showBoardsWithoutEditPermission() {
+        return false;
     }
 
     @Nullable
@@ -232,20 +70,4 @@ public class PrepareCreateActivity extends AppCompatActivity implements Branded
         final CharSequence text = item.getText();
         return TextUtils.isEmpty(text) ? null : text.toString();
     }
-
-    @Override
-    public void applyBrand(int mainColor) {
-        try {
-            if (brandingEnabled) {
-                @ColorInt final int finalMainColor = contrastRatioIsSufficientBigAreas(mainColor, ContextCompat.getColor(this, R.color.primary))
-                        ? mainColor
-                        : isDarkTheme(this) ? Color.WHITE : Color.BLACK;
-                DrawableCompat.setTintList(binding.submit.getBackground(), ColorStateList.valueOf(finalMainColor));
-                binding.submit.setTextColor(ColorUtil.getForegroundColorForBackgroundColor(finalMainColor));
-                binding.cancel.setTextColor(getSecondaryForegroundColorDependingOnTheme(this, mainColor));
-            }
-        } catch (Throwable t) {
-            DeckLog.logError(t);
-        }
-    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/StackAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/StackAdapter.java
index 89c702075..e3e0ad5b5 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/StackAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/StackAdapter.java
@@ -6,14 +6,12 @@ import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
 
-import org.jetbrains.annotations.NotNull;
-
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ItemPrepareCreateStackBinding;
-import it.niedermann.nextcloud.deck.model.full.FullStack;
+import it.niedermann.nextcloud.deck.model.Stack;
 
-public class StackAdapter extends AbstractAdapter<FullStack> {
+public class StackAdapter extends AbstractAdapter<Stack> {
 
     @SuppressWarnings("WeakerAccess")
     public StackAdapter(@NonNull Context context) {
@@ -21,13 +19,13 @@ public class StackAdapter extends AbstractAdapter<FullStack> {
     }
 
     @Override
-    protected long getItemId(@NonNull FullStack item) {
+    protected long getItemId(@NonNull Stack item) {
         return item.getLocalId();
     }
 
-    @NotNull
+    @NonNull
     @Override
-    public View getView(int position, View convertView, @NotNull ViewGroup parent) {
+    public View getView(int position, View convertView, @NonNull ViewGroup parent) {
         final ItemPrepareCreateStackBinding binding;
         if (convertView == null) {
             binding = ItemPrepareCreateStackBinding.inflate(inflater, parent, false);
@@ -35,9 +33,9 @@ public class StackAdapter extends AbstractAdapter<FullStack> {
             binding = ItemPrepareCreateStackBinding.bind(convertView);
         }
 
-        final FullStack item = getItem(position);
+        final Stack item = getItem(position);
         if (item != null) {
-            binding.stackTitle.setText(item.getStack().getTitle());
+            binding.stackTitle.setText(item.getTitle());
         } else {
             DeckLog.logError(new IllegalArgumentException("No item for position " + position));
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/settings/SettingsFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/settings/SettingsFragment.java
index ea8d90f22..04429f225 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/settings/SettingsFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/settings/SettingsFragment.java
@@ -23,6 +23,7 @@ public class SettingsFragment extends PreferenceFragmentCompat implements Brande
     private BrandedSwitchPreference wifiOnlyPref;
     private BrandedSwitchPreference themePref;
     private BrandedSwitchPreference brandingPref;
+    private BrandedSwitchPreference compactPref;
 
     @Override
     public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
@@ -67,6 +68,8 @@ public class SettingsFragment extends PreferenceFragmentCompat implements Brande
             DeckLog.error("Could not find preference with key: \"" + getString(R.string.pref_key_dark_theme) + "\"");
         }
 
+        compactPref = findPreference(getString(R.string.pref_key_compact));
+
         final ListPreference backgroundSyncPref = findPreference(getString(R.string.pref_key_background_sync));
         if (backgroundSyncPref != null) {
             backgroundSyncPref.setOnPreferenceChangeListener((Preference preference, Object newValue) -> {
@@ -92,5 +95,6 @@ public class SettingsFragment extends PreferenceFragmentCompat implements Brande
         wifiOnlyPref.applyBrand(mainColor);
         themePref.applyBrand(mainColor);
         brandingPref.applyBrand(mainColor);
+        compactPref.applyBrand(mainColor);
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/sharetarget/ShareProgressDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/sharetarget/ShareProgressDialogFragment.java
index 271b60489..3028ea952 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/sharetarget/ShareProgressDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/sharetarget/ShareProgressDialogFragment.java
@@ -14,15 +14,16 @@ import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
 import androidx.lifecycle.ViewModelProvider;
 
+import it.niedermann.nextcloud.deck.BuildConfig;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.DialogShareProgressBinding;
 import it.niedermann.nextcloud.deck.exceptions.UploadAttachmentFailedException;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
+import it.niedermann.nextcloud.exception.ExceptionUtil;
 
 import static android.graphics.PorterDuff.Mode;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
-import static it.niedermann.nextcloud.deck.util.ExceptionUtil.getDebugInfos;
 
 public class ShareProgressDialogFragment extends BrandedDialogFragment {
 
@@ -70,7 +71,7 @@ public class ShareProgressDialogFragment extends BrandedDialogFragment {
                 binding.errorReportButton.setOnClickListener((v) -> {
                     final StringBuilder debugInfos = new StringBuilder(exceptionsCount + " attachments failed to upload:");
                     for (Throwable t : exceptions) {
-                        debugInfos.append(getDebugInfos(requireContext(), t, null));
+                        debugInfos.append(ExceptionUtil.INSTANCE.getDebugInfos(requireContext(), t, BuildConfig.FLAVOR));
                     }
                     ExceptionDialogFragment.newInstance(new UploadAttachmentFailedException(debugInfos.toString()), null)
                             .show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/sharetarget/ShareTargetActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/sharetarget/ShareTargetActivity.java
index a64629bd7..3a0005fb1 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/sharetarget/ShareTargetActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/sharetarget/ShareTargetActivity.java
@@ -16,9 +16,9 @@ import androidx.lifecycle.ViewModelProvider;
 import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
 
 import java.io.File;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Date;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
@@ -126,7 +126,7 @@ public class ShareTargetActivity extends MainActivity implements SelectCardListe
                         throw new IllegalArgumentException("MimeType of uri is null. [" + uri + "]");
                     }
                     runOnUiThread(() -> {
-                        final WrappedLiveData<Attachment> liveData = syncManager.addAttachmentToCard(fullCard.getAccountId(), fullCard.getCard().getLocalId(), mimeType, tempFile);
+                        final WrappedLiveData<Attachment> liveData = mainViewModel.addAttachmentToCard(fullCard.getAccountId(), fullCard.getCard().getLocalId(), mimeType, tempFile);
                         liveData.observe(ShareTargetActivity.this, (next) -> {
                             if (liveData.hasError()) {
                                 if (liveData.getError() instanceof NextcloudHttpRequestFailedException && ((NextcloudHttpRequestFailedException) liveData.getError()).getStatusCode() == HTTP_CONFLICT) {
@@ -160,7 +160,7 @@ public class ShareTargetActivity extends MainActivity implements SelectCardListe
                                             ? receivedText
                                             : oldDescription + "\n\n" + receivedText
                             );
-                            WrappedLiveData<FullCard> liveData = syncManager.updateCard(fullCard);
+                            WrappedLiveData<FullCard> liveData = mainViewModel.updateCard(fullCard);
                             observeOnce(liveData, this, (next) -> {
                                 if (liveData.hasError()) {
                                     cardSelected = false;
@@ -173,8 +173,8 @@ public class ShareTargetActivity extends MainActivity implements SelectCardListe
                             break;
                         case 1:
                             final Account currentAccount = mainViewModel.getCurrentAccount();
-                            final DeckComment comment = new DeckComment(receivedText.trim(), currentAccount.getUserName(), new Date());
-                            syncManager.addCommentToCard(currentAccount.getId(), fullCard.getLocalId(), comment);
+                            final DeckComment comment = new DeckComment(receivedText.trim(), currentAccount.getUserName(), Instant.now());
+                            mainViewModel.addCommentToCard(currentAccount.getId(), fullCard.getLocalId(), comment);
                             Toast.makeText(getApplicationContext(), getString(R.string.share_success, "\"" + receivedText + "\"", "\"" + fullCard.getCard().getTitle() + "\""), Toast.LENGTH_LONG).show();
                             finish();
                             break;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/stack/StackAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/stack/StackAdapter.java
index e2cc83372..8fc56759f 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/stack/StackAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/stack/StackAdapter.java
@@ -8,11 +8,11 @@ import androidx.viewpager2.adapter.FragmentStateAdapter;
 import java.util.ArrayList;
 import java.util.List;
 
-import it.niedermann.nextcloud.deck.model.full.FullStack;
+import it.niedermann.nextcloud.deck.model.Stack;
 
 public class StackAdapter extends FragmentStateAdapter {
     @NonNull
-    private List<FullStack> stackList = new ArrayList<>();
+    private final List<Stack> stackList = new ArrayList<>();
 
     public StackAdapter(@NonNull FragmentActivity fragmentActivity) {
         super(fragmentActivity);
@@ -23,7 +23,7 @@ public class StackAdapter extends FragmentStateAdapter {
         return stackList.size();
     }
 
-    public FullStack getItem(int position) {
+    public Stack getItem(int position) {
         return stackList.get(position);
     }
 
@@ -34,7 +34,7 @@ public class StackAdapter extends FragmentStateAdapter {
 
     @Override
     public boolean containsItem(long itemId) {
-        for (FullStack stack : stackList) {
+        for (Stack stack : stackList) {
             if (stack.getLocalId() == itemId) {
                 return true;
             }
@@ -48,9 +48,9 @@ public class StackAdapter extends FragmentStateAdapter {
         return StackFragment.newInstance(stackList.get(position).getLocalId());
     }
 
-    public void setStacks(@NonNull List<FullStack> fullStacks) {
+    public void setStacks(@NonNull List<Stack> stacks) {
         this.stackList.clear();
-        this.stackList.addAll(fullStacks);
+        this.stackList.addAll(stacks);
         notifyDataSetChanged();
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/stack/StackFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/stack/StackFragment.java
index 726a74184..313e6e821 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/stack/StackFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/stack/StackFragment.java
@@ -20,20 +20,27 @@ import java.util.List;
 import it.niedermann.android.crosstabdnd.DragAndDropTab;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.databinding.FragmentStackBinding;
+import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.model.Stack;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 import it.niedermann.nextcloud.deck.ui.MainViewModel;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedFragment;
 import it.niedermann.nextcloud.deck.ui.card.CardAdapter;
 import it.niedermann.nextcloud.deck.ui.card.SelectCardListener;
+import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 import it.niedermann.nextcloud.deck.ui.filter.FilterViewModel;
+import it.niedermann.nextcloud.deck.ui.movecard.MoveCardListener;
 
-public class StackFragment extends BrandedFragment implements DragAndDropTab<CardAdapter> {
+import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
+
+public class StackFragment extends BrandedFragment implements DragAndDropTab<CardAdapter>, MoveCardListener {
 
     private static final String KEY_STACK_ID = "stackId";
 
     private FragmentStackBinding binding;
-    private SyncManager syncManager;
+    private MainViewModel mainViewModel;
     private FragmentActivity activity;
     private OnScrollListener onScrollListener;
 
@@ -61,10 +68,10 @@ public class StackFragment extends BrandedFragment implements DragAndDropTab<Car
 
     @Override
     public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
-        binding = FragmentStackBinding.inflate(inflater, container, false);
         activity = requireActivity();
+        binding = FragmentStackBinding.inflate(inflater, container, false);
+        mainViewModel = new ViewModelProvider(activity).get(MainViewModel.class);
 
-        final MainViewModel mainViewModel = new ViewModelProvider(activity).get(MainViewModel.class);
         final FilterViewModel filterViewModel = new ViewModelProvider(activity).get(FilterViewModel.class);
 
         // This might be a zombie fragment with an empty MainViewModel after Android killed the activity (but not the fragment instance
@@ -74,19 +81,10 @@ public class StackFragment extends BrandedFragment implements DragAndDropTab<Car
             return binding.getRoot();
         }
 
-        syncManager = new SyncManager(activity);
-
-        adapter = new CardAdapter(
-                requireContext(),
-                getChildFragmentManager(),
-                mainViewModel.getCurrentAccount(),
-                mainViewModel.getCurrentBoardLocalId(),
-                mainViewModel.getCurrentBoardRemoteId(),
-                stackId,
-                mainViewModel.currentBoardHasEditPermission(),
-                syncManager,
-                this,
-                (requireActivity() instanceof SelectCardListener) ? (SelectCardListener) requireActivity() : null);
+        adapter = new CardAdapter(requireContext(), getChildFragmentManager(), stackId, mainViewModel, this,
+                (requireActivity() instanceof SelectCardListener)
+                        ? (SelectCardListener) requireActivity()
+                        : null);
         binding.recyclerView.setAdapter(adapter);
 
         if (onScrollListener != null) {
@@ -114,12 +112,12 @@ public class StackFragment extends BrandedFragment implements DragAndDropTab<Car
             }
         });
 
-        cardsLiveData = syncManager.getFullCardsForStack(mainViewModel.getCurrentAccount().getId(), stackId, filterViewModel.getFilterInformation().getValue());
+        cardsLiveData = mainViewModel.getFullCardsForStack(mainViewModel.getCurrentAccount().getId(), stackId, filterViewModel.getFilterInformation().getValue());
         cardsLiveData.observe(getViewLifecycleOwner(), cardsObserver);
 
         filterViewModel.getFilterInformation().observe(getViewLifecycleOwner(), (filterInformation -> {
             cardsLiveData.removeObserver(cardsObserver);
-            cardsLiveData = syncManager.getFullCardsForStack(mainViewModel.getCurrentAccount().getId(), stackId, filterInformation);
+            cardsLiveData = mainViewModel.getFullCardsForStack(mainViewModel.getCurrentAccount().getId(), stackId, filterInformation);
             cardsLiveData.observe(getViewLifecycleOwner(), cardsObserver);
         }));
 
@@ -153,4 +151,17 @@ public class StackFragment extends BrandedFragment implements DragAndDropTab<Car
 
         return fragment;
     }
+
+    @Override
+    public void move(long originAccountId, long originCardLocalId, long targetAccountId, long targetBoardLocalId, long targetStackLocalId) {
+        final WrappedLiveData<Void> liveData = mainViewModel.moveCard(originAccountId, originCardLocalId, targetAccountId, targetBoardLocalId, targetStackLocalId);
+        observeOnce(liveData, requireActivity(), (next) -> {
+            if (liveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(liveData.getError())) {
+                ExceptionDialogFragment.newInstance(liveData.getError(), null).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            } else {
+                DeckLog.log("Moved " + Card.class.getSimpleName() + " \"" + originCardLocalId + "\" to " + Stack.class.getSimpleName() + " \"" + targetStackLocalId + "\"");
+            }
+        });
+    }
+
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/takephoto/TakePhotoActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/takephoto/TakePhotoActivity.java
new file mode 100644
index 000000000..af17464dc
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/takephoto/TakePhotoActivity.java
@@ -0,0 +1,182 @@
+package it.niedermann.nextcloud.deck.ui.takephoto;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.res.ColorStateList;
+import android.net.Uri;
+import android.os.Bundle;
+import android.util.Size;
+import android.view.OrientationEventListener;
+import android.view.Surface;
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.annotation.RequiresApi;
+import androidx.camera.core.Camera;
+import androidx.camera.core.ImageCapture;
+import androidx.camera.core.ImageCaptureException;
+import androidx.camera.core.Preview;
+import androidx.camera.lifecycle.ProcessCameraProvider;
+import androidx.core.content.ContextCompat;
+import androidx.lifecycle.ViewModelProvider;
+
+import com.google.common.util.concurrent.ListenableFuture;
+
+import java.io.File;
+import java.time.Instant;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.concurrent.ExecutionException;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.databinding.ActivityTakePhotoBinding;
+import it.niedermann.nextcloud.deck.ui.branding.BrandedActivity;
+import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
+import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
+import it.niedermann.nextcloud.deck.util.AttachmentUtil;
+
+import static android.os.Build.VERSION_CODES.LOLLIPOP;
+import static it.niedermann.nextcloud.deck.util.MimeTypeUtil.IMAGE_JPEG;
+
+@RequiresApi(LOLLIPOP)
+public class TakePhotoActivity extends BrandedActivity {
+
+    private ActivityTakePhotoBinding binding;
+    private TakePhotoViewModel viewModel;
+
+    private View[] brandedViews;
+
+    private ListenableFuture<ProcessCameraProvider> cameraProviderFuture;
+    private OrientationEventListener orientationEventListener;
+
+    private final DateTimeFormatter fileNameFromCameraFormatter = DateTimeFormatter.ofPattern("'JPG_'yyyyMMdd'_'HHmmss'.jpg'");
+
+    @Override
+    protected void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        Thread.currentThread().setUncaughtExceptionHandler(new ExceptionHandler(this));
+
+        binding = ActivityTakePhotoBinding.inflate(getLayoutInflater());
+        viewModel = new ViewModelProvider(this).get(TakePhotoViewModel.class);
+
+        setContentView(binding.getRoot());
+
+        cameraProviderFuture = ProcessCameraProvider.getInstance(this);
+        cameraProviderFuture.addListener(() -> {
+            try {
+                final ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
+                final Preview previewUseCase = getPreviewUseCase();
+                final ImageCapture captureUseCase = getCaptureUseCase();
+                final Camera camera = cameraProvider.bindToLifecycle(this, viewModel.getCameraSelector(), captureUseCase, previewUseCase);
+
+                viewModel.getCameraSelectorToggleButtonImageResource().observe(this, res -> binding.switchCamera.setImageDrawable(ContextCompat.getDrawable(this, res)));
+                viewModel.getTorchToggleButtonImageResource().observe(this, res -> binding.toggleTorch.setImageDrawable(ContextCompat.getDrawable(this, res)));
+                viewModel.isTorchEnabled().observe(this, enabled -> camera.getCameraControl().enableTorch(enabled));
+
+                binding.toggleTorch.setOnClickListener((v) -> viewModel.toggleTorchEnabled());
+                binding.switchCamera.setOnClickListener((v) -> {
+                    viewModel.toggleCameraSelector();
+                    cameraProvider.unbindAll();
+                    cameraProvider.bindToLifecycle(this, viewModel.getCameraSelector(), captureUseCase, previewUseCase);
+                });
+            } catch (ExecutionException | InterruptedException e) {
+                DeckLog.logError(e);
+                finish();
+            }
+        }, ContextCompat.getMainExecutor(this));
+
+        brandedViews = new View[]{binding.takePhoto, binding.switchCamera, binding.toggleTorch};
+    }
+
+    private ImageCapture getCaptureUseCase() {
+        final ImageCapture captureUseCase = new ImageCapture.Builder().setTargetResolution(new Size(720, 1280)).build();
+
+        orientationEventListener = new OrientationEventListener(this) {
+            @Override
+            public void onOrientationChanged(int orientation) {
+                int rotation;
+
+                // Monitors orientation values to determine the target rotation value
+                if (orientation >= 45 && orientation < 135) {
+                    rotation = Surface.ROTATION_270;
+                } else if (orientation >= 135 && orientation < 225) {
+                    rotation = Surface.ROTATION_180;
+                } else if (orientation >= 225 && orientation < 315) {
+                    rotation = Surface.ROTATION_90;
+                } else {
+                    rotation = Surface.ROTATION_0;
+                }
+
+                captureUseCase.setTargetRotation(rotation);
+            }
+        };
+        orientationEventListener.enable();
+
+        binding.takePhoto.setOnClickListener((v) -> {
+            binding.takePhoto.setEnabled(false);
+            final String photoFileName = Instant.now().atZone(ZoneId.systemDefault()).format(fileNameFromCameraFormatter);
+            try {
+                final File photoFile = AttachmentUtil.getTempCacheFile(this, "photos/" + photoFileName);
+                final ImageCapture.OutputFileOptions options = new ImageCapture.OutputFileOptions.Builder(photoFile).build();
+                captureUseCase.takePicture(options, ContextCompat.getMainExecutor(this), new ImageCapture.OnImageSavedCallback() {
+                    @Override
+                    public void onImageSaved(@NonNull ImageCapture.OutputFileResults outputFileResults) {
+                        final Uri savedUri = Uri.fromFile(photoFile);
+                        DeckLog.info("onImageSaved - savedUri: " + savedUri.toString());
+                        setResult(RESULT_OK, new Intent().setDataAndType(savedUri, IMAGE_JPEG));
+                        finish();
+                    }
+
+                    @Override
+                    public void onError(@NonNull ImageCaptureException e) {
+                        e.printStackTrace();
+                        //noinspection ResultOfMethodCallIgnored
+                        photoFile.delete();
+                        binding.takePhoto.setEnabled(true);
+                    }
+                });
+            } catch (Exception e) {
+                ExceptionDialogFragment.newInstance(e, null).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
+
+        return captureUseCase;
+    }
+
+    private Preview getPreviewUseCase() {
+        Preview previewUseCase = new Preview.Builder().build();
+        previewUseCase.setSurfaceProvider(binding.preview.getSurfaceProvider());
+        return previewUseCase;
+    }
+
+    @Override
+    protected void onPause() {
+        if (this.orientationEventListener != null) {
+            this.orientationEventListener.disable();
+        }
+        super.onPause();
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+        if (this.orientationEventListener != null) {
+            this.orientationEventListener.enable();
+        }
+    }
+
+    @RequiresApi(LOLLIPOP)
+    public static Intent createIntent(@NonNull Context context) {
+        return new Intent(context, TakePhotoActivity.class).setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
+    }
+
+    @Override
+    public void applyBrand(int mainColor) {
+        final ColorStateList colorStateList = ColorStateList.valueOf(mainColor);
+        for (View v : brandedViews) {
+            v.setBackgroundTintList(colorStateList);
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/takephoto/TakePhotoViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/takephoto/TakePhotoViewModel.java
new file mode 100644
index 000000000..a71291ff2
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/takephoto/TakePhotoViewModel.java
@@ -0,0 +1,57 @@
+package it.niedermann.nextcloud.deck.ui.takephoto;
+
+import androidx.annotation.NonNull;
+import androidx.camera.core.CameraSelector;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+import androidx.lifecycle.Transformations;
+import androidx.lifecycle.ViewModel;
+
+import it.niedermann.nextcloud.deck.R;
+
+import static androidx.camera.core.CameraSelector.DEFAULT_BACK_CAMERA;
+import static androidx.camera.core.CameraSelector.DEFAULT_FRONT_CAMERA;
+
+public class TakePhotoViewModel extends ViewModel {
+
+    @NonNull
+    private CameraSelector cameraSelector = DEFAULT_BACK_CAMERA;
+    @NonNull
+    private final MutableLiveData<Integer> cameraSelectorToggleButtonImageResource = new MutableLiveData<>(R.drawable.ic_baseline_camera_front_24);
+    @NonNull
+    private final MutableLiveData<Boolean> torchEnabled = new MutableLiveData<>(false);
+
+    @NonNull
+    public CameraSelector getCameraSelector() {
+        return this.cameraSelector;
+    }
+
+    public LiveData<Integer> getCameraSelectorToggleButtonImageResource() {
+        return this.cameraSelectorToggleButtonImageResource;
+    }
+
+    public void toggleCameraSelector() {
+        if (this.cameraSelector == DEFAULT_BACK_CAMERA) {
+            this.cameraSelector = DEFAULT_FRONT_CAMERA;
+            this.cameraSelectorToggleButtonImageResource.postValue(R.drawable.ic_baseline_camera_rear_24);
+        } else {
+            this.cameraSelector = DEFAULT_BACK_CAMERA;
+            this.cameraSelectorToggleButtonImageResource.postValue(R.drawable.ic_baseline_camera_front_24);
+        }
+    }
+
+    public void toggleTorchEnabled() {
+        //noinspection ConstantConditions
+        this.torchEnabled.postValue(!this.torchEnabled.getValue());
+    }
+
+    public LiveData<Boolean> isTorchEnabled() {
+        return this.torchEnabled;
+    }
+
+    public LiveData<Integer> getTorchToggleButtonImageResource() {
+        return Transformations.map(isTorchEnabled(), enabled -> enabled
+                ? R.drawable.ic_baseline_flash_off_24
+                : R.drawable.ic_baseline_flash_on_24);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/ColorChooser.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/ColorChooser.java
index 30dc0ada4..0dd431ff9 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/ColorChooser.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/ColorChooser.java
@@ -2,6 +2,7 @@ package it.niedermann.nextcloud.deck.ui.view;
 
 import android.content.Context;
 import android.content.res.TypedArray;
+import android.graphics.Color;
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -9,31 +10,31 @@ import android.view.ViewGroup;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
 
 import com.google.android.flexbox.FlexboxLayout;
 import com.skydoves.colorpickerview.listeners.ColorEnvelopeListener;
 
+import java.util.Arrays;
+
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.WidgetColorChooserBinding;
 import it.niedermann.nextcloud.deck.util.ViewUtil;
 
-import static it.niedermann.nextcloud.deck.util.DimensionUtil.dpToPx;
-
 public class ColorChooser extends LinearLayout {
 
-    private WidgetColorChooserBinding binding;
-
-    private final FlexboxLayout.LayoutParams params = new FlexboxLayout.LayoutParams(
-            ViewGroup.LayoutParams.WRAP_CONTENT,
-            ViewGroup.LayoutParams.WRAP_CONTENT
-    );
+    private final WidgetColorChooserBinding binding;
 
-    private Context context;
-    private String[] colors;
+    private final Context context;
+    private final int[] colors;
 
-    private String selectedColor;
-    private String previouslySelectedColor;
+    @ColorInt
+    private int selectedColor;
+    @ColorInt
+    private int previouslySelectedColor;
     @Nullable
     private ImageView previouslySelectedImageView;
 
@@ -41,17 +42,22 @@ public class ColorChooser extends LinearLayout {
         super(context, attrs);
         this.context = context;
 
-        params.setMargins(0, dpToPx(context, R.dimen.spacer_1x), 0, 0);
+        final FlexboxLayout.LayoutParams params = new FlexboxLayout.LayoutParams(
+                ViewGroup.LayoutParams.WRAP_CONTENT,
+                ViewGroup.LayoutParams.WRAP_CONTENT
+        );
+        params.setMargins(0, DimensionUtil.INSTANCE.dpToPx(context, R.dimen.spacer_1x), 0, 0);
         params.setFlexBasisPercent(.15f);
 
-        TypedArray a = context.obtainStyledAttributes(attrs,
-                R.styleable.ColorChooser, 0, 0);
-        colors = getResources().getStringArray(a.getResourceId(R.styleable.ColorChooser_colors, 0));
+        final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ColorChooser, 0, 0);
+        colors = Arrays.stream(getResources().getStringArray(a.getResourceId(R.styleable.ColorChooser_colors, 0)))
+                .mapToInt(Color::parseColor)
+                .toArray();
         a.recycle();
 
         binding = WidgetColorChooserBinding.inflate(LayoutInflater.from(context), this, true);
-        for (final String color : colors) {
-            ImageView image = new ImageView(getContext());
+        for (final int color : colors) {
+            final ImageView image = new ImageView(getContext());
             image.setLayoutParams(params);
             image.setOnClickListener((imageView) -> {
                 if (previouslySelectedImageView != null) { // null when first selection
@@ -61,7 +67,7 @@ public class ColorChooser extends LinearLayout {
                 selectedColor = color;
                 this.previouslySelectedColor = color;
                 this.previouslySelectedImageView = image;
-                binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_alpha_colorize_36dp, R.color.board_default_custom_color));
+                binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_alpha_colorize_36dp, ContextCompat.getColor(context, R.color.board_default_custom_color)));
                 binding.customColorPicker.setVisibility(View.GONE);
                 binding.brightnessSlide.setVisibility(View.GONE);
             });
@@ -84,19 +90,20 @@ public class ColorChooser extends LinearLayout {
                 previouslySelectedImageView.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_grey600_36dp, previouslySelectedColor));
                 previouslySelectedImageView = null;
             }
-            String customColor = "#" + envelope.getHexCode().substring(2);
+            @ColorInt
+            final int customColor = envelope.getColor();
             selectedColor = customColor;
             previouslySelectedColor = customColor;
             binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.circle_alpha_colorize_36dp, selectedColor));
         });
     }
 
-    public void selectColor(String newColor) {
+    public void selectColor(@ColorInt int newColor) {
         boolean newColorIsCustomColor = true;
         selectedColor = newColor;
         for (int i = 0; i < colors.length; i++) {
-            if (colors[i].equals(newColor)) {
-                binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_alpha_colorize_36dp, R.color.board_default_custom_color));
+            if (colors[i] == newColor) {
+                binding.customColorChooser.setImageDrawable(ViewUtil.getTintedImageView(this.context, R.drawable.circle_alpha_colorize_36dp, ContextCompat.getColor(context, R.color.board_default_custom_color)));
                 binding.colorPicker.getChildAt(i).performClick();
                 newColorIsCustomColor = false;
                 break;
@@ -107,7 +114,8 @@ public class ColorChooser extends LinearLayout {
         }
     }
 
-    public String getSelectedColor() {
+    @ColorInt
+    public int getSelectedColor() {
         return this.selectedColor;
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/OverlappingAvatars.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/OverlappingAvatars.java
index 501d33106..0facc385c 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/OverlappingAvatars.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/OverlappingAvatars.java
@@ -10,6 +10,7 @@ import android.widget.RelativeLayout;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Px;
+import androidx.core.content.ContextCompat;
 import androidx.core.graphics.drawable.DrawableCompat;
 
 import com.bumptech.glide.Glide;
@@ -17,12 +18,11 @@ import com.bumptech.glide.request.RequestOptions;
 
 import java.util.List;
 
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.User;
 
-import static it.niedermann.nextcloud.deck.util.DimensionUtil.dpToPx;
-
 public class OverlappingAvatars extends RelativeLayout {
     final int maxAvatarCount;
     @Px
@@ -44,11 +44,12 @@ public class OverlappingAvatars extends RelativeLayout {
     public OverlappingAvatars(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
         maxAvatarCount = context.getResources().getInteger(R.integer.max_avatar_count);
-        avatarBorderSize = dpToPx(context, R.dimen.avatar_size_small_overlapping_border);
-        avatarSize = dpToPx(context, R.dimen.avatar_size_small) + avatarBorderSize * 2;
-        overlapPx = dpToPx(context, R.dimen.avatar_size_small_overlapping);
-        borderDrawable = getResources().getDrawable(R.drawable.avatar_border);
-        DrawableCompat.setTint(borderDrawable, getResources().getColor(R.color.bg_card));
+        avatarBorderSize = DimensionUtil.INSTANCE.dpToPx(context, R.dimen.avatar_size_small_overlapping_border);
+        avatarSize = DimensionUtil.INSTANCE.dpToPx(context, R.dimen.avatar_size_small) + avatarBorderSize * 2;
+        overlapPx = DimensionUtil.INSTANCE.dpToPx(context, R.dimen.avatar_size_small_overlapping);
+        borderDrawable = ContextCompat.getDrawable(context, R.drawable.avatar_border);
+        assert borderDrawable != null;
+        DrawableCompat.setTint(borderDrawable, ContextCompat.getColor(context, R.color.bg_card));
     }
 
     public void setAvatars(@NonNull Account account, @NonNull List<User> assignedUsers) {
@@ -70,6 +71,7 @@ public class OverlappingAvatars extends RelativeLayout {
             avatar.requestLayout();
             Glide.with(context)
                     .load(account.getUrl() + "/index.php/avatar/" + Uri.encode(assignedUsers.get(avatarCount).getUid()) + "/" + avatarSize)
+                    .placeholder(R.drawable.ic_person_grey600_24dp)
                     .error(R.drawable.ic_person_grey600_24dp)
                     .apply(RequestOptions.circleCropTransform())
                     .into(avatar);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/SquareConstraintLayout.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/SquareConstraintLayout.java
new file mode 100644
index 000000000..0912a07dd
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/SquareConstraintLayout.java
@@ -0,0 +1,35 @@
+package it.niedermann.nextcloud.deck.ui.view;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.os.Build;
+import android.util.AttributeSet;
+
+import androidx.constraintlayout.widget.ConstraintLayout;
+
+public class SquareConstraintLayout extends ConstraintLayout {
+
+    public SquareConstraintLayout(Context context) {
+        super(context);
+    }
+
+    public SquareConstraintLayout(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public SquareConstraintLayout(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    public SquareConstraintLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        // Set a square layout.
+        super.onMeasure(widthMeasureSpec, widthMeasureSpec);
+    }
+
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labelchip/CompactLabelChip.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labelchip/CompactLabelChip.java
new file mode 100644
index 000000000..a2a50430c
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labelchip/CompactLabelChip.java
@@ -0,0 +1,21 @@
+package it.niedermann.nextcloud.deck.ui.view.labelchip;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Px;
+
+import it.niedermann.android.util.DimensionUtil;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Label;
+
+@SuppressLint("ViewConstructor")
+public class CompactLabelChip extends LabelChip {
+
+    public CompactLabelChip(@NonNull Context context, @NonNull Label label, @Px int gutter) {
+        super(context, label, gutter);
+        params.setFlexBasisPercent(1 / 6.5f);
+        setHeight(DimensionUtil.INSTANCE.dpToPx(context, R.dimen.compact_label_height));
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labelchip/DefaultLabelChip.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labelchip/DefaultLabelChip.java
new file mode 100644
index 000000000..80e44d7e0
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labelchip/DefaultLabelChip.java
@@ -0,0 +1,21 @@
+package it.niedermann.nextcloud.deck.ui.view.labelchip;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Px;
+
+import it.niedermann.nextcloud.deck.model.Label;
+
+import static android.text.TextUtils.TruncateAt.MIDDLE;
+
+@SuppressLint("ViewConstructor")
+public class DefaultLabelChip extends LabelChip {
+
+    public DefaultLabelChip(@NonNull Context context, @NonNull Label label, @Px int gutter) {
+        super(context, label, gutter);
+        setText(label.getTitle());
+        setEllipsize(MIDDLE);
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/LabelChip.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labelchip/LabelChip.java
index db4e123d3..83853f0b2 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/LabelChip.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labelchip/LabelChip.java
@@ -1,9 +1,8 @@
-package it.niedermann.nextcloud.deck.ui.view;
+package it.niedermann.nextcloud.deck.ui.view.labelchip;
 
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.res.ColorStateList;
-import android.graphics.Color;
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
@@ -12,26 +11,24 @@ import androidx.annotation.Px;
 import com.google.android.flexbox.FlexboxLayout;
 import com.google.android.material.chip.Chip;
 
+import it.niedermann.android.util.ColorUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.model.Label;
-import it.niedermann.nextcloud.deck.util.ColorUtil;
-
-import static android.text.TextUtils.TruncateAt.MIDDLE;
 
 @SuppressLint("ViewConstructor")
 public class LabelChip extends Chip {
 
     private final Label label;
 
+    protected final FlexboxLayout.LayoutParams params = new FlexboxLayout.LayoutParams(
+            ViewGroup.LayoutParams.WRAP_CONTENT,
+            ViewGroup.LayoutParams.WRAP_CONTENT
+    );
+
     public LabelChip(@NonNull Context context, @NonNull Label label, @Px int gutter) {
         super(context);
         this.label = label;
 
-        FlexboxLayout.LayoutParams params = new FlexboxLayout.LayoutParams(
-                ViewGroup.LayoutParams.WRAP_CONTENT,
-                ViewGroup.LayoutParams.WRAP_CONTENT
-        );
-
         params.setMargins(0, 0, gutter, 0);
         setLayoutParams(params);
         setEnsureMinTouchTargetSize(false);
@@ -42,15 +39,13 @@ public class LabelChip extends Chip {
         setTextStartPadding(gutter);
         setTextEndPadding(gutter);
         setChipEndPadding(gutter);
-
-        setText(label.getTitle());
-        setEllipsize(MIDDLE);
+        setClickable(false);
 
         try {
-            int labelColor = Color.parseColor("#" + label.getColor());
+            int labelColor = label.getColor();
             ColorStateList c = ColorStateList.valueOf(labelColor);
             setChipBackgroundColor(c);
-            setTextColor(ColorUtil.getForegroundColorForBackgroundColor(labelColor));
+            setTextColor(ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(labelColor));
         } catch (IllegalArgumentException e) {
             DeckLog.logError(e);
         }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labellayout/CompactLabelLayout.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labellayout/CompactLabelLayout.java
new file mode 100644
index 000000000..1c5e35d97
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labellayout/CompactLabelLayout.java
@@ -0,0 +1,22 @@
+package it.niedermann.nextcloud.deck.ui.view.labellayout;
+
+import android.content.Context;
+import android.util.AttributeSet;
+
+import androidx.annotation.NonNull;
+
+import it.niedermann.nextcloud.deck.model.Label;
+import it.niedermann.nextcloud.deck.ui.view.labelchip.CompactLabelChip;
+import it.niedermann.nextcloud.deck.ui.view.labelchip.LabelChip;
+
+public class CompactLabelLayout extends LabelLayout {
+
+    public CompactLabelLayout(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    protected LabelChip createLabelChip(@NonNull Label label) {
+        return new CompactLabelChip(getContext(), label, gutter);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labellayout/DefaultLabelLayout.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labellayout/DefaultLabelLayout.java
new file mode 100644
index 000000000..f2d6d0752
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labellayout/DefaultLabelLayout.java
@@ -0,0 +1,21 @@
+package it.niedermann.nextcloud.deck.ui.view.labellayout;
+
+import android.content.Context;
+import android.util.AttributeSet;
+
+import androidx.annotation.NonNull;
+
+import it.niedermann.nextcloud.deck.model.Label;
+import it.niedermann.nextcloud.deck.ui.view.labelchip.DefaultLabelChip;
+
+public class DefaultLabelLayout extends LabelLayout {
+
+    public DefaultLabelLayout(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    protected DefaultLabelChip createLabelChip(@NonNull Label label) {
+        return new DefaultLabelChip(getContext(), label, gutter);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/LabelLayout.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labellayout/LabelLayout.java
index 814c63ce1..3db539e53 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/LabelLayout.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/labellayout/LabelLayout.java
@@ -1,4 +1,4 @@
-package it.niedermann.nextcloud.deck.ui.view;
+package it.niedermann.nextcloud.deck.ui.view.labellayout;
 
 import android.content.Context;
 import android.util.AttributeSet;
@@ -11,21 +11,22 @@ import com.google.android.flexbox.FlexboxLayout;
 import java.util.LinkedList;
 import java.util.List;
 
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.model.Label;
+import it.niedermann.nextcloud.deck.ui.view.labelchip.LabelChip;
 
-import static it.niedermann.nextcloud.deck.util.DimensionUtil.dpToPx;
-
-public class LabelLayout extends FlexboxLayout {
+public abstract class LabelLayout extends FlexboxLayout {
 
     @Px
-    private int gutter;
-    private List<LabelChip> chipList = new LinkedList<>();
+    final protected int gutter;
+    @NonNull
+    final private List<LabelChip> chipList = new LinkedList<>();
 
     public LabelLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
-        this.gutter = dpToPx(context, R.dimen.spacer_1hx);
+        this.gutter = DimensionUtil.INSTANCE.dpToPx(context, R.dimen.spacer_1hx);
     }
 
     /**
@@ -82,9 +83,11 @@ public class LabelLayout extends FlexboxLayout {
                     continue labelList;
                 }
             }
-            LabelChip chip = new LabelChip(getContext(), label, gutter);
+            final LabelChip chip = createLabelChip(label);
             addView(chip);
             chipList.add(chip);
         }
     }
+
+    protected abstract LabelChip createLabelChip(@NonNull Label label);
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SelectCardForWidgetActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SelectCardForWidgetActivity.java
index 8c1fbe1fa..fe6e969e7 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SelectCardForWidgetActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SelectCardForWidgetActivity.java
@@ -45,7 +45,7 @@ public class SelectCardForWidgetActivity extends MainActivity implements SelectC
 
     @Override
     public void onCardSelected(FullCard fullCard) {
-        syncManager.addOrUpdateSingleCardWidget(appWidgetId, mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId(), fullCard.getLocalId());
+        mainViewModel.addOrUpdateSingleCardWidget(appWidgetId, mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId(), fullCard.getLocalId());
         final Intent updateIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE, null,
                 getApplicationContext(), SingleCardWidget.class)
                 .putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidget.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidget.java
index 783f98e00..b44b80d1b 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidget.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidget.java
@@ -43,7 +43,7 @@ public class SingleCardWidget extends AppWidgetProvider {
                     views.setTextViewText(R.id.description, fullModel.getFullCard().getCard().getDescription());
 
                     if (fullModel.getFullCard().getCard().getDueDate() != null) {
-                        views.setTextViewText(R.id.card_due_date, DateUtil.getRelativeDateTimeString(context, fullModel.getFullCard().getCard().getDueDate().getTime()));
+                        views.setTextViewText(R.id.card_due_date, DateUtil.getRelativeDateTimeString(context, fullModel.getFullCard().getCard().getDueDate().toEpochMilli()));
                         // TODO Use multiple views for background colors and only set the necessary to View.VISIBLE
                         // https://stackoverflow.com/a/3376537
                         // Because otherwise using Reflection is the only way
@@ -141,13 +141,10 @@ public class SingleCardWidget extends AppWidgetProvider {
         super.onDeleted(context, appWidgetIds);
     }
 
-
     /**
      * Updates UI data of all {@link SingleCardWidget} instances
      */
     public static void notifyDatasetChanged(Context context) {
-        Intent intent = new Intent(context, SingleCardWidget.class);
-        intent.setAction("android.appwidget.action.APPWIDGET_UPDATE");
-        context.sendBroadcast(intent);
+        context.sendBroadcast(new Intent(context, SingleCardWidget.class).setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE));
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidget.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidget.java
new file mode 100644
index 000000000..cb179953c
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidget.java
@@ -0,0 +1,121 @@
+package it.niedermann.nextcloud.deck.ui.widget.stack;
+
+import android.app.PendingIntent;
+import android.appwidget.AppWidgetManager;
+import android.appwidget.AppWidgetProvider;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Bundle;
+import android.widget.RemoteViews;
+
+import java.util.NoSuchElementException;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.appwidgets.StackWidgetModel;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.ui.MainActivity;
+import it.niedermann.nextcloud.deck.ui.card.EditActivity;
+
+import static android.appwidget.AppWidgetManager.ACTION_APPWIDGET_UPDATE;
+
+public class StackWidget extends AppWidgetProvider {
+    public static final String ACCOUNT_ID_KEY = "stack_widget_account_id";
+    public static final String ACCOUNT_KEY = "stack_widget_account";
+    public static final String STACK_ID_KEY = "stack_widget_stack_id";
+    public static final String BUNDLE_KEY = "stack_widget_bundle";
+    private static final int PENDING_INTENT_OPEN_APP_RQ = 0;
+    private static final int PENDING_INTENT_EDIT_CARD_RQ = 1;
+
+    static void updateAppWidget(Context context, AppWidgetManager awm, int[] appWidgetIds, Account account) {
+        final SyncManager syncManager = new SyncManager(context);
+
+        for (int appWidgetId : appWidgetIds) {
+            new Thread(() -> {
+                try {
+                    final StackWidgetModel model = syncManager.getStackWidgetModelDirectly(appWidgetId);
+                    RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_stack);
+                    Intent serviceIntent = new Intent(context, StackWidgetService.class);
+
+                    serviceIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
+                    serviceIntent.putExtra(ACCOUNT_ID_KEY + appWidgetId, model.getAccountId());
+                    serviceIntent.putExtra(STACK_ID_KEY + appWidgetId, model.getStackId());
+                    if (account != null) {
+                        Bundle extras = new Bundle();
+                        extras.putSerializable(StackWidget.ACCOUNT_KEY + appWidgetId, account);
+                        serviceIntent.putExtra(BUNDLE_KEY + appWidgetId, extras);
+                    }
+                    serviceIntent.setData(Uri.parse(serviceIntent.toUri(Intent.URI_INTENT_SCHEME)));
+
+                    Intent intent = new Intent(Intent.ACTION_MAIN);
+                    intent.setComponent(new ComponentName(context.getPackageName(), MainActivity.class.getName()));
+                    PendingIntent pendingIntent = PendingIntent.getActivity(context,  PENDING_INTENT_OPEN_APP_RQ,
+                            intent, PendingIntent.FLAG_UPDATE_CURRENT);
+                    views.setOnClickPendingIntent(R.id.widget_stack_header_rl, pendingIntent);
+
+                    PendingIntent templatePI = PendingIntent.getActivity(context, PENDING_INTENT_EDIT_CARD_RQ,
+                            new Intent(context, EditActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);
+
+                    views.setPendingIntentTemplate(R.id.stack_widget_lv, templatePI);
+                    views.setRemoteAdapter(R.id.stack_widget_lv, serviceIntent);
+                    views.setEmptyView(R.id.stack_widget_lv, R.id.widget_stack_placeholder_iv);
+                    awm.notifyAppWidgetViewDataChanged(appWidgetId, R.id.stack_widget_lv);
+                    awm.updateAppWidget(appWidgetId, views);
+                } catch (NoSuchElementException e) {
+                    // onUpdate has been triggered before the user finished configuring the widget
+                }
+            }).start();
+        }
+    }
+
+    @Override
+    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
+        super.onUpdate(context, appWidgetManager, appWidgetIds);
+        updateAppWidget(context, appWidgetManager, appWidgetIds, null);
+    }
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        final Account account;
+
+        super.onReceive(context, intent);
+
+        AppWidgetManager awm = AppWidgetManager.getInstance(context);
+
+        if (intent.getAction() != null) {
+            if (intent.getAction().equals(ACTION_APPWIDGET_UPDATE)) {
+                if (intent.hasExtra(BUNDLE_KEY)) {
+                    Bundle extras = intent.getBundleExtra(StackWidget.BUNDLE_KEY);
+                    account = (Account) extras.getSerializable(ACCOUNT_KEY);
+
+                    if (intent.hasExtra(AppWidgetManager.EXTRA_APPWIDGET_ID)) {
+                        if (intent.getExtras() != null) {
+                            updateAppWidget(context, awm, new int[]{intent.getExtras().getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, -1)}, account);
+                        }
+                    } else {
+                        updateAppWidget(context, awm, awm.getAppWidgetIds(new ComponentName(context, StackWidget.class)), account);
+                    }
+                }
+            }
+        }
+    }
+
+    @Override
+    public void onDeleted(Context context, int[] appWidgetIds) {
+        super.onDeleted(context, appWidgetIds);
+        final SyncManager syncManager = new SyncManager(context);
+
+        for (int appWidgetId : appWidgetIds) {
+            syncManager.deleteStackWidgetModel(appWidgetId);
+        }
+    }
+
+    /**
+     * Updates UI data of all {@link StackWidget} instances
+     */
+    public static void notifyDatasetChanged(Context context) {
+        context.sendBroadcast(new Intent(context, StackWidget.class).setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE));
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationActivity.java
new file mode 100644
index 000000000..96b5cf672
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationActivity.java
@@ -0,0 +1,68 @@
+package it.niedermann.nextcloud.deck.ui.widget.stack;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Intent;
+import android.os.Bundle;
+
+import androidx.appcompat.app.ActionBar;
+import androidx.lifecycle.ViewModelProvider;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.ui.PickStackActivity;
+
+public class StackWidgetConfigurationActivity extends PickStackActivity {
+    private int appWidgetId;
+    private StackWidgetConfigurationViewModel stackWidgetConfigurationViewModel;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        stackWidgetConfigurationViewModel = new ViewModelProvider(this).get(StackWidgetConfigurationViewModel.class);
+
+        final ActionBar actionBar = getSupportActionBar();
+        if (actionBar != null) {
+            actionBar.setTitle(R.string.add_stack_widget);
+        }
+
+        setResult(RESULT_CANCELED);
+        final Bundle extras = getIntent().getExtras();
+
+        if (extras != null) {
+            appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID,
+                    AppWidgetManager.INVALID_APPWIDGET_ID);
+        }
+
+        if (appWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID) {
+            DeckLog.error("INVALID_APPWIDGET_ID");
+            finish();
+        }
+    }
+
+    @Override
+    protected void onSubmit(Account account, long boardId, long stackId) {
+        final Bundle extras = new Bundle();
+
+        stackWidgetConfigurationViewModel.addStackWidget(appWidgetId, account.getId(), stackId, false);
+        Intent updateIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE, null,
+                getApplicationContext(), StackWidget.class);
+        extras.putSerializable(StackWidget.ACCOUNT_KEY, account);
+        extras.putInt(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
+
+        // The `extras` bundle is added to the intent this way because using putExtras(extras) 
+        // would have the OS attempt to reassemle the data and cause a crash 
+        // when it finds classes that are only known to this application.
+        updateIntent.putExtra(StackWidget.BUNDLE_KEY, extras);
+        setResult(RESULT_OK, updateIntent);
+        getApplicationContext().sendBroadcast(updateIntent);
+
+        finish();
+    }
+
+    @Override
+    protected boolean showBoardsWithoutEditPermission() {
+        return true;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationViewModel.java
new file mode 100644
index 000000000..cc669accf
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetConfigurationViewModel.java
@@ -0,0 +1,23 @@
+package it.niedermann.nextcloud.deck.ui.widget.stack;
+
+import android.app.Application;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
+
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+
+@SuppressWarnings("WeakerAccess")
+public class StackWidgetConfigurationViewModel extends AndroidViewModel {
+
+    private final SyncManager syncManager;
+
+    public StackWidgetConfigurationViewModel(@NonNull Application application) {
+        super(application);
+        this.syncManager = new SyncManager(application);
+    }
+
+    public void addStackWidget(int appWidgetId, long accountId, long stackId, boolean darkTheme) {
+        syncManager.addStackWidget(appWidgetId, accountId, stackId, darkTheme);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetFactory.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetFactory.java
new file mode 100644
index 000000000..87f357e20
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetFactory.java
@@ -0,0 +1,134 @@
+package it.niedermann.nextcloud.deck.ui.widget.stack;
+
+import android.appwidget.AppWidgetManager;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+import android.widget.RemoteViews;
+import android.widget.RemoteViewsService;
+
+import androidx.lifecycle.LiveData;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.full.FullBoard;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.model.full.FullStack;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.ui.card.EditActivity;
+
+public class StackWidgetFactory implements RemoteViewsService.RemoteViewsFactory {
+    private final Context context;
+    private final int appWidgetId;
+    private final long accountId;
+    private final long stackId;
+
+    private Account account;
+    private FullStack stack;
+    private List<FullCard> cardList;
+
+    StackWidgetFactory(Context context, Intent intent) {
+        this.context = context;
+        appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
+                AppWidgetManager.INVALID_APPWIDGET_ID);
+        accountId = intent.getLongExtra(StackWidget.ACCOUNT_ID_KEY + appWidgetId, -1);
+        stackId = intent.getLongExtra(StackWidget.STACK_ID_KEY + appWidgetId, -1);
+        if (intent.hasExtra(StackWidget.BUNDLE_KEY + appWidgetId)) {
+            account = (Account) intent.getBundleExtra(StackWidget.BUNDLE_KEY + appWidgetId).getSerializable(StackWidget.ACCOUNT_KEY + appWidgetId);
+        }
+    }
+
+    @Override
+    public void onCreate() {
+        SyncManager syncManager = new SyncManager(context);
+
+        LiveData<FullStack> stackLiveData = syncManager.getStack(accountId, stackId);
+        stackLiveData.observeForever((FullStack fullStack) -> {
+            if (fullStack != null) {
+                RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_stack);
+                stack = fullStack;
+                views.setTextViewText(R.id.widget_stack_title_tv, stack.getStack().getTitle());
+
+                LiveData<FullBoard> fullBoardLiveData = syncManager.getFullBoardById(accountId, stack.getStack().getBoardId());
+                fullBoardLiveData.observeForever((FullBoard fullBoard) -> {
+                    if (fullBoard != null) {
+                        views.setInt(R.id.widget_stack_header_icon, "setColorFilter", fullBoard.getBoard().getColor());
+                        notifyAppWidgetUpdate(views);
+                    }
+                });
+
+                LiveData<List<FullCard>> fullCardData = syncManager.getFullCardsForStack(accountId, stackId, null);
+                fullCardData.observeForever((List<FullCard> fullCards) -> cardList = fullCards);
+                notifyAppWidgetUpdate(views);
+            }
+        });
+    }
+
+    @Override
+    public void onDataSetChanged() {
+
+    }
+
+
+    @Override
+    public void onDestroy() {
+
+    }
+
+    @Override
+    public int getCount() {
+        return stack == null ? 0 : stack.getCards().size();
+    }
+
+    @Override
+    public RemoteViews getViewAt(int i) {
+        RemoteViews widget_entry;
+
+        if (cardList == null || i > (cardList.size() - 1) || cardList.get(i) == null) {
+            DeckLog.error("Card not found at position " + i);
+            return null;
+        }
+
+        FullCard card = cardList.get(i);
+
+        widget_entry = new RemoteViews(context.getPackageName(), R.layout.widget_stack_entry);
+        widget_entry.setTextViewText(R.id.widget_entry_content_tv, card.card.getTitle());
+
+        final Intent intent = EditActivity.createEditCardIntent(context, account, stack.getStack().getBoardId(), card.getCard().getLocalId());
+        intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME)));
+        widget_entry.setOnClickFillInIntent(R.id.widget_stack_entry, intent);
+
+        return widget_entry;
+    }
+
+    @Override
+    public RemoteViews getLoadingView() {
+        return null;
+    }
+
+    @Override
+    public int getViewTypeCount() {
+        return 1;
+    }
+
+    @Override
+    public long getItemId(int i) {
+        return i;
+    }
+
+    @Override
+    public boolean hasStableIds() {
+        return true;
+    }
+
+    private void notifyAppWidgetUpdate(RemoteViews views) {
+        AppWidgetManager awm = AppWidgetManager.getInstance(context);
+        int[] appWidgetIds = awm.getAppWidgetIds(new ComponentName(context, StackWidget.class));
+        awm.notifyAppWidgetViewDataChanged(appWidgetIds, R.id.stack_widget_lv);
+        awm.updateAppWidget(appWidgetId, views);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetService.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetService.java
new file mode 100644
index 000000000..9299a96e2
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/stack/StackWidgetService.java
@@ -0,0 +1,11 @@
+package it.niedermann.nextcloud.deck.ui.widget.stack;
+
+import android.content.Intent;
+import android.widget.RemoteViewsService;
+
+public class StackWidgetService extends RemoteViewsService {
+    @Override
+    public RemoteViewsFactory onGetViewFactory(Intent intent) {
+        return new StackWidgetFactory(this.getApplicationContext(), intent);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/AttachmentUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/AttachmentUtil.java
index 6b2d6925f..ef3e14b37 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/AttachmentUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/AttachmentUtil.java
@@ -1,9 +1,16 @@
 package it.niedermann.nextcloud.deck.util;
 
 import android.content.Context;
+import android.content.Intent;
 import android.net.Uri;
+import android.text.TextUtils;
+import android.webkit.MimeTypeMap;
+import android.widget.Toast;
 
+import androidx.annotation.DrawableRes;
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.annotation.Px;
 
 import java.io.File;
 import java.io.FileNotFoundException;
@@ -12,6 +19,9 @@ import java.io.IOException;
 import java.io.InputStream;
 
 import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Attachment;
+import it.niedermann.nextcloud.deck.model.ocs.Version;
 
 /**
  * Created by stefan on 07.03.20.
@@ -22,38 +32,121 @@ public class AttachmentUtil {
     private AttachmentUtil() {
     }
 
-    public static String getRemoteUrl(String accountUrl, long cardRemoteId, long attachmentRemoteId) {
+    /**
+     * @return a link to the thumbnail of the given {@link Attachment}.
+     * If a thumbnail is not available (see {@link Version#supportsFileAttachments()}), a link to
+     * the {@link Attachment} itself will be returned instead.
+     */
+    public static String getThumbnailUrl(@NonNull Version version, @NonNull String accountUrl, @NonNull Long cardRemoteId, @NonNull Attachment attachment, @Px int previewSize) {
+        return version.supportsFileAttachments() && !TextUtils.isEmpty(String.valueOf(attachment.getFileId()))
+                ? accountUrl + "/index.php/core/preview?fileId=" + attachment.getFileId() + "&x=" + previewSize + "&y=" + previewSize
+                : getRemoteOrLocalUrl(accountUrl, cardRemoteId, attachment);
+    }
+
+    /**
+     * @return {@link AttachmentUtil#getRemoteUrl} or {@link Attachment#getLocalPath()} as fallback
+     * in case this {@param attachment} has not yet been synced.
+     */
+    @Nullable
+    public static String getRemoteOrLocalUrl(@NonNull String accountUrl, @Nullable Long cardRemoteId, @NonNull Attachment attachment) {
+        return (attachment.getId() == null || cardRemoteId == null)
+                ? attachment.getLocalPath()
+                : getRemoteUrl(accountUrl, cardRemoteId, attachment.getId());
+    }
+
+    /**
+     * Tries to open the given {@link Attachment} in web browser. Displays a toast on failure.
+     */
+    public static void openAttachmentInBrowser(@NonNull Context context, @NonNull String accountUrl, Long cardRemoteId, Long attachmentRemoteId) {
+        if (cardRemoteId == null) {
+            Toast.makeText(context, R.string.card_does_not_yet_exist, Toast.LENGTH_LONG).show();
+            DeckLog.logError(new IllegalArgumentException("cardRemoteId must not be null."));
+            return;
+        }
+        if (attachmentRemoteId == null) {
+            Toast.makeText(context, R.string.attachment_does_not_yet_exist, Toast.LENGTH_LONG).show();
+            DeckLog.logError(new IllegalArgumentException("attachmentRemoteId must not be null."));
+            return;
+        }
+        context.startActivity(new Intent(Intent.ACTION_VIEW).setData(Uri.parse(AttachmentUtil.getRemoteUrl(accountUrl, cardRemoteId, attachmentRemoteId))));
+    }
+
+    private static String getRemoteUrl(@NonNull String accountUrl, @NonNull Long cardRemoteId, @NonNull Long attachmentRemoteId) {
         return accountUrl + "/index.php/apps/deck/cards/" + cardRemoteId + "/attachment/" + attachmentRemoteId;
     }
 
-    public static File copyContentUriToTempFile(@NonNull Context context, @NonNull Uri currentUri, long accountId, Long localId) throws IOException, IllegalArgumentException {
-        String fullTempPath = context.getApplicationContext().getFilesDir().getAbsolutePath() + "/attachments/account-" + accountId + "/card-" + (localId == null ? "pending-creation" : localId) + '/' + UriUtils.getDisplayNameForUri(currentUri, context);
-        DeckLog.verbose("----- fullTempPath: " + fullTempPath);
-        InputStream inputStream = context.getContentResolver().openInputStream(currentUri);
+    public static File copyContentUriToTempFile(@NonNull Context context, @NonNull Uri currentUri, long accountId, Long localCardId) throws IOException, IllegalArgumentException {
+        final InputStream inputStream = context.getContentResolver().openInputStream(currentUri);
         if (inputStream == null) {
             throw new IOException("Could not open input stream for " + currentUri.getPath());
         }
-        File cacheFile = new File(fullTempPath);
-        File tempDir = cacheFile.getParentFile();
+        final File cacheFile = getTempCacheFile(context, "attachments/account-" + accountId + "/card-" + (localCardId == null ? "pending-creation" : localCardId) + '/' + UriUtils.getDisplayNameForUri(currentUri, context));
+        final FileOutputStream outputStream = new FileOutputStream(cacheFile);
+        byte[] buffer = new byte[4096];
+
+        int count;
+        while ((count = inputStream.read(buffer)) > 0) {
+            outputStream.write(buffer, 0, count);
+        }
+        DeckLog.verbose("----- wrote");
+        return cacheFile;
+    }
+
+    /**
+     * Creates a new {@link File}
+     */
+    public static File getTempCacheFile(@NonNull Context context, String fileName) throws IOException {
+        File cacheFile = new File(context.getApplicationContext().getFilesDir().getAbsolutePath() + "/" + fileName);
+
+        DeckLog.verbose("- Full path for new cache file: " + cacheFile.getAbsolutePath());
+
+        final File tempDir = cacheFile.getParentFile();
         if (tempDir == null) {
-            throw new FileNotFoundException("could not cacheFile.getPranetFile()");
+            throw new FileNotFoundException("could not cacheFile.getParentFile()");
         }
         if (!tempDir.exists()) {
-            if (!tempDir.mkdirs()) {
+            DeckLog.verbose("-- The folder in which the new file should be created does not exist yet. Trying to create it...");
+            if (tempDir.mkdirs()) {
+                DeckLog.verbose("--- Creation successful");
+            } else {
                 throw new IOException("Directory for temporary file does not exist and could not be created.");
             }
         }
-        if (!cacheFile.createNewFile()) {
+
+        DeckLog.verbose("- Try to create actual cache file");
+        if (cacheFile.createNewFile()) {
+            DeckLog.verbose("-- Successfully created cache file");
+        } else {
             throw new IOException("Failed to create cacheFile");
         }
-        FileOutputStream outputStream = new FileOutputStream(fullTempPath);
-        byte[] buffer = new byte[4096];
 
-        int count;
-        while ((count = inputStream.read(buffer)) > 0) {
-            outputStream.write(buffer, 0, count);
-        }
-        DeckLog.verbose("----- wrote");
         return cacheFile;
     }
+
+    @DrawableRes
+    public static int getIconForMimeType(@NonNull String mimeType) {
+        if (TextUtils.isEmpty(mimeType)) {
+            return R.drawable.ic_attach_file_grey600_24dp;
+        } else if (MimeTypeUtil.isAudio(mimeType)) {
+            return R.drawable.ic_music_note_grey600_24dp;
+        } else if (MimeTypeUtil.isVideo(mimeType)) {
+            return R.drawable.ic_local_movies_grey600_24dp;
+        } else if (MimeTypeUtil.isPdf(mimeType)) {
+            return R.drawable.ic_baseline_picture_as_pdf_24;
+        } else if (MimeTypeUtil.isContact(mimeType)) {
+            return R.drawable.ic_baseline_contact_mail_24;
+        } else {
+            return R.drawable.ic_attach_file_grey600_24dp;
+        }
+    }
+
+    public static String getMimeType(@Nullable String url) {
+        String type = null;
+        String extension = MimeTypeMap.getFileExtensionFromUrl(url);
+        if (extension != null) {
+            type = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
+        }
+        return type;
+    }
+
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/ClipboardUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/ClipboardUtil.java
deleted file mode 100644
index 1dad224e9..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/ClipboardUtil.java
+++ /dev/null
@@ -1,38 +0,0 @@
-package it.niedermann.nextcloud.deck.util;
-
-import android.content.ClipData;
-import android.content.ClipboardManager;
-import android.content.Context;
-import android.widget.Toast;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-
-import it.niedermann.nextcloud.deck.DeckLog;
-import it.niedermann.nextcloud.deck.R;
-
-import static android.content.Context.CLIPBOARD_SERVICE;
-
-public class ClipboardUtil {
-
-    private ClipboardUtil() {
-    }
-
-    public static boolean copyToClipboard(@NonNull Context context, @Nullable String text) {
-        return copyToClipboard(context, text, text);
-    }
-
-    public static boolean copyToClipboard(@NonNull Context context, @Nullable String label, @Nullable String text) {
-        final ClipboardManager clipboardManager = (ClipboardManager) context.getSystemService(CLIPBOARD_SERVICE);
-        if (clipboardManager == null) {
-            DeckLog.error("ClipboardManager is null");
-            Toast.makeText(context, R.string.could_not_copy_to_clipboard, Toast.LENGTH_LONG).show();
-            return false;
-        }
-        final ClipData clipData = ClipData.newPlainText(label, text);
-        clipboardManager.setPrimaryClip(clipData);
-        DeckLog.info("Copied to clipboard: [" + label + "] \"" + text + "\"");
-        Toast.makeText(context, R.string.copied_to_clipboard, Toast.LENGTH_SHORT).show();
-        return true;
-    }
-}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/ColorUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/ColorUtil.java
deleted file mode 100644
index 08354c5fb..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/ColorUtil.java
+++ /dev/null
@@ -1,165 +0,0 @@
-package it.niedermann.nextcloud.deck.util;
-
-import android.graphics.Color;
-
-import androidx.annotation.ColorInt;
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.core.util.Pair;
-
-import java.util.HashMap;
-import java.util.Map;
-
-public final class ColorUtil {
-
-    private static final Map<ColorPair, Boolean> CONTRAST_RATIO_SUFFICIENT_CACHE = new HashMap<>();
-    private static final Map<Integer, Integer> FOREGROUND_CACHE = new HashMap<>();
-    private static final Map<Integer, Boolean> IS_DARK_COLOR_CACHE = new HashMap<>();
-
-    private ColorUtil() {
-    }
-
-    @ColorInt
-    public static int getForegroundColorForBackgroundColor(@ColorInt int color) {
-        Integer ret = FOREGROUND_CACHE.get(color);
-        if (ret == null) {
-            if (Color.TRANSPARENT == color)
-                ret = Color.BLACK;
-            else if (isColorDark(color))
-                ret = Color.WHITE;
-            else
-                ret = Color.BLACK;
-
-            FOREGROUND_CACHE.put(color, ret);
-        }
-        return ret;
-    }
-
-    /**
-     * @return well formatted string starting with a hash followed by 6 hex numbers that is parsable by {@link Color#parseColor(String)}.
-     */
-    public static String formatColorToParsableHexString(String input) {
-        if (input == null) {
-            throw new IllegalArgumentException("input color string is null");
-        }
-        if (isParsableValidHexColorString(input)) {
-            return input;
-        }
-        final char[] chars = input.replaceAll("#", "").toCharArray();
-        final StringBuilder sb = new StringBuilder(7).append("#");
-        if (chars.length == 6) {
-            sb.append(chars);
-        } else if (chars.length == 3) {
-            for (char c : chars) {
-                sb.append(c).append(c);
-            }
-        } else {
-            throw new IllegalArgumentException("unparsable color string: \"" + input + "\"");
-        }
-        final String formattedHexColor = sb.toString();
-        if (isParsableValidHexColorString(formattedHexColor)) {
-            return formattedHexColor;
-        } else {
-            throw new IllegalArgumentException("\"" + input + "\" is not a valid color string. Result of tried normalizing: " + formattedHexColor);
-        }
-    }
-
-    /**
-     * Checking for {@link Color#parseColor(String)} being able to parse the input is the important part because we don't know the implementation and rely on it to be able to parse the color.
-     *
-     * @return true, if the input starts with a hash followed by 6 characters of hex numbers and is parsable by {@link Color#parseColor(String)}.
-     */
-    private static boolean isParsableValidHexColorString(@NonNull String input) {
-        try {
-            Color.parseColor(input);
-            return input.matches("#[a-fA-F0-9]{6}");
-        } catch (Exception e) {
-            return false;
-        }
-    }
-
-    public static boolean isColorDark(@ColorInt int color) {
-        Boolean ret = IS_DARK_COLOR_CACHE.get(color);
-        if (ret == null) {
-            ret = getBrightness(color) < 200;
-            IS_DARK_COLOR_CACHE.put(color, ret);
-        }
-        return ret;
-    }
-
-    private static int getBrightness(@ColorInt int color) {
-        final int[] rgb = {Color.red(color), Color.green(color), Color.blue(color)};
-
-        return (int) Math.sqrt(rgb[0] * rgb[0] * .241 + rgb[1]
-                * rgb[1] * .691 + rgb[2] * rgb[2] * .068);
-    }
-
-    // ---------------------------------------------------
-    // Based on https://github.com/LeaVerou/contrast-ratio
-    // ---------------------------------------------------
-
-    public static boolean contrastRatioIsSufficient(@ColorInt int colorOne, @ColorInt int colorTwo) {
-        ColorPair key = new ColorPair(colorOne, colorTwo);
-        Boolean ret = CONTRAST_RATIO_SUFFICIENT_CACHE.get(key);
-        if (ret == null) {
-            ret = getContrastRatio(colorOne, colorTwo) > 3d;
-            CONTRAST_RATIO_SUFFICIENT_CACHE.put(key, ret);
-            return ret;
-        }
-        return ret;
-    }
-
-    public static boolean contrastRatioIsSufficientBigAreas(@ColorInt int colorOne, @ColorInt int colorTwo) {
-        ColorPair key = new ColorPair(colorOne, colorTwo);
-        Boolean ret = CONTRAST_RATIO_SUFFICIENT_CACHE.get(key);
-        if (ret == null) {
-            ret = getContrastRatio(colorOne, colorTwo) > 1.47d;
-            CONTRAST_RATIO_SUFFICIENT_CACHE.put(key, ret);
-            return ret;
-        }
-        return ret;
-    }
-
-    public static double getContrastRatio(@ColorInt int colorOne, @ColorInt int colorTwo) {
-        final double lum1 = getLuminanace(colorOne);
-        final double lum2 = getLuminanace(colorTwo);
-        final double brightest = Math.max(lum1, lum2);
-        final double darkest = Math.min(lum1, lum2);
-        return (brightest + 0.05) / (darkest + 0.05);
-    }
-
-    private static double getLuminanace(@ColorInt int color) {
-        final int[] rgb = {Color.red(color), Color.green(color), Color.blue(color)};
-        return getSubcolorLuminance(rgb[0]) * 0.2126 + getSubcolorLuminance(rgb[1]) * 0.7152 + getSubcolorLuminance(rgb[2]) * 0.0722;
-    }
-
-    private static double getSubcolorLuminance(@ColorInt int color) {
-        final double value = color / 255d;
-        return value <= 0.03928
-                ? value / 12.92
-                : Math.pow((value + 0.055) / 1.055, 2.4);
-    }
-
-    private static class ColorPair extends Pair<Integer, Integer> {
-
-        private ColorPair(@Nullable Integer first, @Nullable Integer second) {
-            super(first, second);
-        }
-
-        @SuppressWarnings({"EqualsWhichDoesntCheckParameterClass", "NumberEquality"})
-        @Override
-        public boolean equals(Object o) {
-            final ColorPair colorPair = (ColorPair) o;
-            if (first != colorPair.first) return false;
-            return second == colorPair.second;
-        }
-
-        @SuppressWarnings("ConstantConditions")
-        @Override
-        public int hashCode() {
-            int result = first;
-            result = 31 * result + second;
-            return result;
-        }
-    }
-}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/DateUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/DateUtil.java
index 5c2ffd76c..ac88519ff 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/DateUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/DateUtil.java
@@ -3,9 +3,9 @@ package it.niedermann.nextcloud.deck.util;
 import android.content.Context;
 import android.text.format.DateUtils;
 
-import java.util.Date;
-import java.util.TimeZone;
-import java.util.concurrent.TimeUnit;
+import androidx.annotation.NonNull;
+
+import java.time.ZonedDateTime;
 
 import it.niedermann.nextcloud.deck.R;
 
@@ -15,48 +15,9 @@ public final class DateUtil {
     private DateUtil() {
     }
 
-    public static Date nowInGMT() {
-        return convertToGMT(new Date());
-    }
-
-    private static Date convertToGMT(Date date ){
-        TimeZone tz = TimeZone.getDefault();
-        Date ret = new Date( date.getTime() - tz.getRawOffset() );
-
-        // if we are now in DST, back off by the delta.  Note that we are checking the GMT date, this is the KEY.
-        if ( tz.inDaylightTime( ret )){
-            Date dstDate = new Date( ret.getTime() - tz.getDSTSavings() );
-
-            // check to make sure we have not crossed back into standard time
-            // this happens when we are on the cusp of DST (7pm the day before the change for PDT)
-            if ( tz.inDaylightTime( dstDate )){
-                ret = dstDate;
-            }
-        }
-        return ret;
-    }
-
-    /**
-     * Get difference between 2 dates in days (hours, minutes will be set to zero).
-     *
-     * @param sourceDateFrom  start date
-     * @param sourceDateUntil end date
-     * @return difference between the to dates in days.
-     */
-    public static long getDayDifference(Date sourceDateFrom, Date sourceDateUntil) {
-        Date dateFrom = new Date(sourceDateFrom.getTime());
-        dateFrom.setHours(0);
-        dateFrom.setMinutes(0);
-
-        Date dateUntil = new Date(sourceDateUntil.getTime());
-        dateUntil.setHours(0);
-        dateUntil.setMinutes(0);
-
-        return TimeUnit.DAYS.convert(dateUntil.getTime() - dateFrom.getTime(), TimeUnit.MILLISECONDS);
-    }
-
-    public static CharSequence getRelativeDateTimeString(Context context, long time) {
-        if ((System.currentTimeMillis() - time) < 60 * 1000 && System.currentTimeMillis() > time) {
+    public static CharSequence getRelativeDateTimeString(@NonNull Context context, long time) {
+        long now = ZonedDateTime.now().toInstant().toEpochMilli();
+        if ((now - time) < 60 * 1000 && now > time) {
             // < 60 seconds -> seconds ago
             return context.getString(R.string.seconds_ago);
         } else {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/DeckColorUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/DeckColorUtil.java
new file mode 100644
index 000000000..e01d0ec29
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/DeckColorUtil.java
@@ -0,0 +1,59 @@
+package it.niedermann.nextcloud.deck.util;
+
+import androidx.annotation.ColorInt;
+import androidx.annotation.Nullable;
+import androidx.core.util.Pair;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import it.niedermann.android.util.ColorUtil;
+
+public final class DeckColorUtil {
+
+    private static final Map<ColorPair, Boolean> CONTRAST_RATIO_SUFFICIENT_CACHE = new HashMap<>();
+
+    public static boolean contrastRatioIsSufficient(@ColorInt int colorOne, @ColorInt int colorTwo) {
+        ColorPair key = new ColorPair(colorOne, colorTwo);
+        Boolean ret = CONTRAST_RATIO_SUFFICIENT_CACHE.get(key);
+        if (ret == null) {
+            ret = ColorUtil.INSTANCE.getContrastRatio(colorOne, colorTwo) > 3d;
+            CONTRAST_RATIO_SUFFICIENT_CACHE.put(key, ret);
+            return ret;
+        }
+        return ret;
+    }
+
+    public static boolean contrastRatioIsSufficientBigAreas(@ColorInt int colorOne, @ColorInt int colorTwo) {
+        ColorPair key = new ColorPair(colorOne, colorTwo);
+        Boolean ret = CONTRAST_RATIO_SUFFICIENT_CACHE.get(key);
+        if (ret == null) {
+            ret = ColorUtil.INSTANCE.getContrastRatio(colorOne, colorTwo) > 1.47d;
+            CONTRAST_RATIO_SUFFICIENT_CACHE.put(key, ret);
+            return ret;
+        }
+        return ret;
+    }
+
+    private static class ColorPair extends Pair<Integer, Integer> {
+
+        private ColorPair(@Nullable Integer first, @Nullable Integer second) {
+            super(first, second);
+        }
+
+        @SuppressWarnings({"EqualsWhichDoesntCheckParameterClass", "NumberEquality"})
+        @Override
+        public boolean equals(Object o) {
+            final ColorPair colorPair = (ColorPair) o;
+            if (first != colorPair.first) return false;
+            return second == colorPair.second;
+        }
+
+        @Override
+        public int hashCode() {
+            int result = first;
+            result = 31 * result + second;
+            return result;
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/DimensionUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/DimensionUtil.java
deleted file mode 100644
index 6ff22eace..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/DimensionUtil.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package it.niedermann.nextcloud.deck.util;
-
-import android.content.Context;
-
-import androidx.annotation.DimenRes;
-import androidx.annotation.NonNull;
-import androidx.annotation.Px;
-
-public final class DimensionUtil {
-    private DimensionUtil() {
-    }
-
-    @Px
-    public static int dpToPx(@NonNull Context context, @DimenRes int resource) {
-        return context.getResources().getDimensionPixelSize(resource);
-    }
-}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/DrawerMenuUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/DrawerMenuUtil.java
index 7457c0df7..1a88bec97 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/DrawerMenuUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/DrawerMenuUtil.java
@@ -7,6 +7,7 @@ import android.view.SubMenu;
 import androidx.annotation.NonNull;
 import androidx.appcompat.widget.AppCompatImageButton;
 import androidx.appcompat.widget.PopupMenu;
+import androidx.core.content.ContextCompat;
 import androidx.fragment.app.FragmentActivity;
 
 import java.util.List;
@@ -38,12 +39,12 @@ public class DrawerMenuUtil {
         SubMenu boardsMenu = menu.addSubMenu(R.string.simple_boards);
         int index = 0;
         for (Board board : boards) {
-            MenuItem m = boardsMenu.add(Menu.NONE, index++, Menu.NONE, board.getTitle()).setIcon(ViewUtil.getTintedImageView(context, R.drawable.circle_grey600_36dp, "#" + board.getColor()));
+            MenuItem m = boardsMenu.add(Menu.NONE, index++, Menu.NONE, board.getTitle()).setIcon(ViewUtil.getTintedImageView(context, R.drawable.circle_grey600_36dp, board.getColor()));
             if (currentServerVersionIsSupported) {
                 if (board.isPermissionManage()) {
                     AppCompatImageButton contextMenu = new AppCompatImageButton(context);
                     contextMenu.setBackgroundDrawable(null);
-                    contextMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_menu, R.color.grey600));
+                    contextMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_menu, ContextCompat.getColor(context, R.color.grey600)));
                     contextMenu.setOnClickListener((v) -> {
                         PopupMenu popup = new PopupMenu(context, contextMenu);
                         popup.getMenuInflater().inflate(R.menu.navigation_context_menu, popup.getMenu());
@@ -53,25 +54,27 @@ public class DrawerMenuUtil {
                         }
                         popup.setOnMenuItemClickListener((MenuItem item) -> {
                             final String editBoard = context.getString(R.string.edit_board);
-                            switch (item.getItemId()) {
-                                case SHARE_BOARD_ID:
-                                    AccessControlDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), AccessControlDialogFragment.class.getSimpleName());
-                                    return true;
-                                case R.id.edit_board:
-                                    EditBoardDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), editBoard);
-                                    return true;
-                                case R.id.manage_labels:
-                                    ManageLabelsDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), editBoard);
-                                    return true;
-                                case R.id.archive_board:
-                                    context.onArchive(board);
-                                    return true;
-                                case R.id.delete_board:
-                                    DeleteBoardDialogFragment.newInstance(board).show(context.getSupportFragmentManager(), DeleteBoardDialogFragment.class.getCanonicalName());
-                                    return true;
-                                default:
-                                    return false;
+                            int itemId = item.getItemId();
+                            if (itemId == SHARE_BOARD_ID) {
+                                AccessControlDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), AccessControlDialogFragment.class.getSimpleName());
+                                return true;
+                            } else if (itemId == R.id.edit_board) {
+                                EditBoardDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), editBoard);
+                                return true;
+                            } else if (itemId == R.id.manage_labels) {
+                                ManageLabelsDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), editBoard);
+                                return true;
+                            } else if (itemId == R.id.clone_board) {
+                                context.onClone(board);
+                                return true;
+                            } else if (itemId == R.id.archive_board) {
+                                context.onArchive(board);
+                                return true;
+                            } else if (itemId == R.id.delete_board) {
+                                DeleteBoardDialogFragment.newInstance(board).show(context.getSupportFragmentManager(), DeleteBoardDialogFragment.class.getCanonicalName());
+                                return true;
                             }
+                            return false;
                         });
                         popup.show();
                     });
@@ -79,7 +82,7 @@ public class DrawerMenuUtil {
                 } else if (board.isPermissionShare()) {
                     AppCompatImageButton contextMenu = new AppCompatImageButton(context);
                     contextMenu.setBackgroundDrawable(null);
-                    contextMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_share_grey600_18dp, R.color.grey600));
+                    contextMenu.setImageDrawable(ViewUtil.getTintedImageView(context, R.drawable.ic_share_grey600_18dp, ContextCompat.getColor(context, R.color.grey600)));
                     contextMenu.setOnClickListener((v) -> AccessControlDialogFragment.newInstance(board.getLocalId()).show(context.getSupportFragmentManager(), AccessControlDialogFragment.class.getSimpleName()));
                     m.setActionView(contextMenu);
                 }
@@ -87,7 +90,7 @@ public class DrawerMenuUtil {
         }
 
         if (hasArchivedBoards) {
-            boardsMenu.add(Menu.NONE, MENU_ID_ARCHIVED_BOARDS, Menu.NONE, R.string.archived_boards).setIcon(ViewUtil.getTintedImageView(context, R.drawable.ic_archive_white_24dp, R.color.grey600));
+            boardsMenu.add(Menu.NONE, MENU_ID_ARCHIVED_BOARDS, Menu.NONE, R.string.archived_boards).setIcon(ViewUtil.getTintedImageView(context, R.drawable.ic_archive_white_24dp, ContextCompat.getColor(context, R.color.grey600)));
         }
 
         if (currentServerVersionIsSupported) {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/ExceptionUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/ExceptionUtil.java
deleted file mode 100644
index 8599f0b6d..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/ExceptionUtil.java
+++ /dev/null
@@ -1,81 +0,0 @@
-package it.niedermann.nextcloud.deck.util;
-
-import android.content.Context;
-import android.content.pm.PackageManager;
-import android.os.Build;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.annotation.UiThread;
-
-import com.nextcloud.android.sso.exceptions.NextcloudFilesAppNotInstalledException;
-import com.nextcloud.android.sso.helper.VersionCheckHelper;
-import com.nextcloud.android.sso.ui.UiExceptionManager;
-
-import java.io.PrintWriter;
-import java.io.StringWriter;
-
-import it.niedermann.nextcloud.deck.BuildConfig;
-import it.niedermann.nextcloud.deck.DeckLog;
-import it.niedermann.nextcloud.deck.model.Account;
-
-public class ExceptionUtil {
-
-    private ExceptionUtil() {
-
-    }
-
-    public static String getDebugInfos(@NonNull Context context, Throwable throwable, @Nullable Account account) {
-        return "" +
-                getAppVersions(context, account) +
-                "\n\n---\n" +
-                getDeviceInfos() +
-                "\n\n---" +
-                "\n\n" +
-                getStacktraceOf(throwable);
-    }
-
-    private static String getAppVersions(Context context, @Nullable Account account) {
-        String versions = ""
-                + "App Version: " + BuildConfig.VERSION_NAME + "\n"
-                + "App Version Code: " + BuildConfig.VERSION_CODE + "\n"
-                + "App Flavor: " + BuildConfig.FLAVOR + "\n";
-
-        if (account != null) {
-            versions += "\n";
-            versions += "Deck Server Version: " + account.getServerDeckVersion() + "\n";
-        }
-
-        versions += "\n";
-        try {
-            versions += "Files App Version Code: " + VersionCheckHelper.getNextcloudFilesVersionCode(context);
-        } catch (PackageManager.NameNotFoundException e) {
-            versions += "Files App Version Code: " + e.getMessage();
-            e.printStackTrace();
-        }
-        return versions;
-    }
-
-    private static String getDeviceInfos() {
-        return ""
-                + "\nOS Version: " + System.getProperty("os.version") + "(" + Build.VERSION.INCREMENTAL + ")"
-                + "\nOS API Level: " + Build.VERSION.SDK_INT
-                + "\nDevice: " + Build.DEVICE
-                + "\nManufacturer: " + Build.MANUFACTURER
-                + "\nModel (and Product): " + Build.MODEL + " (" + Build.PRODUCT + ")";
-    }
-
-    private static String getStacktraceOf(Throwable e) {
-        StringWriter sw = new StringWriter();
-        e.printStackTrace(new PrintWriter(sw));
-        return sw.toString();
-    }
-
-    @UiThread
-    public static void handleNextcloudFilesAppNotInstalledException(@NonNull Context context, @NonNull NextcloudFilesAppNotInstalledException exception) {
-        UiExceptionManager.showDialogForException(context, exception);
-        DeckLog.warn("=============================================================");
-        DeckLog.warn("Nextcloud app is not installed. Cannot choose account");
-        exception.printStackTrace();
-    }
-}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/MimeTypeUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/MimeTypeUtil.java
index 0390bf96d..04694a058 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/MimeTypeUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/MimeTypeUtil.java
@@ -6,6 +6,7 @@ import java.util.Locale;
 
 public class MimeTypeUtil {
 
+    public static final String IMAGE_JPEG = "image/jpeg";
     public static final String TEXT_PLAIN = "text/plain";
     public static final String TEXT_VCARD = "text/vcard";
     public static final String APPLICATION_PDF = "application/pdf";
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/ProjectUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/ProjectUtil.java
new file mode 100644
index 000000000..58c465290
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/ProjectUtil.java
@@ -0,0 +1,90 @@
+package it.niedermann.nextcloud.deck.util;
+
+import android.net.Uri;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import java.net.URL;
+
+import it.niedermann.nextcloud.deck.model.Account;
+
+public class ProjectUtil {
+
+    private ProjectUtil() {
+    }
+
+    @NonNull
+    public static Uri getResourceUri(@NonNull Account account, @NonNull String link) throws IllegalArgumentException {
+        try {
+            // Assume link contains a fully qualified Uri including host
+            final URL u = new URL(link);
+            return Uri.parse(u.toString());
+        } catch (Throwable linkIsNotQualified) {
+            try {
+                // Assume link is a absolute path that needs to be concatenated with account url for a complete Uri
+                final URL u = new URL(account.getUrl() + link);
+                return Uri.parse(u.toString());
+            } catch (Throwable throwable) {
+                throw new IllegalArgumentException("Could not parse " + Uri.class.getSimpleName() + ": " + link, throwable);
+            }
+        }
+    }
+
+    /**
+     * extracts the values of board- and card-ID from url.
+     * Depending on what kind of url it gets, it will return a long[] of length 1 or 2:
+     * If the url contains both values, you'll get 2, if it contains only the board, you'll get 1.
+     * <p>
+     * The order is fixed here: [boardId, cardId]
+     *
+     * @param url to extract from
+     * @return extracted and parsed values as long[] with length 1-2
+     */
+    public static long[] extractBoardIdAndCardIdFromUrl(@Nullable String url) throws IllegalArgumentException {
+        if (url == null) {
+            throw new IllegalArgumentException("provided url is null");
+        }
+        url = url.trim();
+        if (url.length() == 0) {
+            throw new IllegalArgumentException("trimmed url is empty");
+        }
+        // extract important part
+        String[] splitByPrefix = url.split(".*(index\\.php/)?apps/deck(/#)?/board/");
+        // split into board- and card part
+        if (splitByPrefix.length < 2) {
+            throw new IllegalArgumentException("This URL doesn't seem to be an URL containing the boardId: \"" + url + "\"");
+        }
+        String[] splitBySeparator = splitByPrefix[1].split("/card/");
+
+        // remove any unexpected stuff
+        if (splitBySeparator.length > 1 && splitBySeparator[1].contains("/")) {
+            splitBySeparator[1] = splitBySeparator[1].split("/")[0];
+        }
+        if (splitBySeparator.length > 0 && splitBySeparator[0].contains("/")) {
+            splitBySeparator[0] = splitBySeparator[0].split("/")[0];
+        }
+
+        if (splitBySeparator.length < 1) {
+            throw new IllegalArgumentException("This URL doesn't seem to be an URL containing the boardId: \"" + url + "\"");
+        }
+
+        // return result
+        long boardId = Long.parseLong(splitBySeparator[0]);
+        if (boardId < 1) {
+            throw new IllegalArgumentException("Invalid boardId \"" + boardId + "\" for url \"" + url + "\".");
+        }
+        if (splitBySeparator.length == 1) {
+            return new long[]{boardId};
+        } else if (splitBySeparator.length == 2) {
+            long cardId = Long.parseLong(splitBySeparator[1]);
+            if (cardId > 0) {
+                return new long[]{boardId, cardId};
+            } else {
+                return new long[]{boardId};
+            }
+        } else {
+            throw new IllegalArgumentException("could not parse URL for boardId and/or cardId: \"" + url + "\"");
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/SpannableUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/SpannableUtil.java
index 54f3c8adc..c2ba6f46a 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/SpannableUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/SpannableUtil.java
@@ -21,28 +21,28 @@ import it.niedermann.nextcloud.deck.R;
 
 public class SpannableUtil {
     public static SpannableString strong(@NonNull CharSequence text) {
-        SpannableString span = new SpannableString(text);
+        final SpannableString span = new SpannableString(text);
         span.setSpan(new StyleSpan(Typeface.BOLD), 0, span.length(), 0);
         return span;
     }
 
     public static SpannableString disabled(@NonNull CharSequence text, @NonNull Context context) {
-        SpannableString span = new SpannableString(text);
+        final SpannableString span = new SpannableString(text);
         span.setSpan(new StyleSpan(Typeface.ITALIC), 0, span.length(), 0);
         span.setSpan(new ForegroundColorSpan(ContextCompat.getColor(context, R.color.fg_secondary)), 0, span.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
         return span;
     }
 
     public static SpannableString url(@NonNull CharSequence text, @NonNull String target) {
-        SpannableString span = new SpannableString(text);
+        final SpannableString span = new SpannableString(text);
         span.setSpan(new URLSpan(target), 0, span.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
         return span;
     }
 
     public static void setTextWithURL(@NonNull TextView textView, @NonNull Resources resources, @StringRes int containerTextId, @StringRes int linkLabelId, @StringRes int urlId) {
-        String linkLabel = resources.getString(linkLabelId);
-        String finalText = resources.getString(containerTextId, linkLabel);
-        SpannableStringBuilder finalTextBuilder = new SpannableStringBuilder(finalText);
+        final String linkLabel = resources.getString(linkLabelId);
+        final String finalText = resources.getString(containerTextId, linkLabel);
+        final SpannableStringBuilder finalTextBuilder = new SpannableStringBuilder(finalText);
         finalTextBuilder.setSpan(new URLSpan(resources.getString(urlId)), finalText.indexOf(linkLabel), finalText.indexOf(linkLabel) + linkLabel.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
         textView.setText(finalTextBuilder);
         textView.setMovementMethod(new LinkMovementMethod());
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/VCardUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/VCardUtil.java
new file mode 100644
index 000000000..274af332d
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/VCardUtil.java
@@ -0,0 +1,42 @@
+package it.niedermann.nextcloud.deck.util;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.database.Cursor;
+import android.graphics.Color;
+import android.net.Uri;
+import android.provider.ContactsContract;
+
+import androidx.annotation.ColorInt;
+import androidx.annotation.NonNull;
+
+import java.util.NoSuchElementException;
+import java.util.Objects;
+
+import it.niedermann.nextcloud.deck.R;
+
+public class VCardUtil {
+
+    private VCardUtil() {
+        // You shall not pass
+    }
+
+    public static Uri getVCardContentUri(@NonNull Context context, @NonNull Uri contactUri) throws NoSuchElementException {
+        final ContentResolver cr = context.getContentResolver();
+        try (final Cursor cursor = cr.query(contactUri, null, null, null, null)) {
+            if (cursor != null && cursor.moveToFirst()) {
+                final String lookupKey = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts.LOOKUP_KEY));
+                return Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_VCARD_URI, lookupKey);
+            } else {
+                throw new NoSuchElementException("Cursor has zero entries");
+            }
+        }
+    }
+
+    @ColorInt
+    public static int getColorBasedOnDisplayName(@NonNull Context context, @NonNull String displayName) {
+        final String[] colors = context.getResources().getStringArray(R.array.board_default_colors);
+        final int hashCode = Objects.hashCode(displayName);
+        return Color.parseColor(colors[(hashCode < 0 ? hashCode * -1 : hashCode) % colors.length]);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/ViewUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/ViewUtil.java
index 6abbde557..fbc7fc3fc 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/ViewUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/ViewUtil.java
@@ -3,7 +3,6 @@ package it.niedermann.nextcloud.deck.util;
 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.graphics.Bitmap;
-import android.graphics.Color;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.text.Spannable;
@@ -12,10 +11,13 @@ import android.text.style.ImageSpan;
 import android.widget.ImageView;
 import android.widget.TextView;
 
+import androidx.annotation.ColorInt;
+import androidx.annotation.ColorRes;
 import androidx.annotation.DrawableRes;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.Px;
+import androidx.core.content.ContextCompat;
 import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.core.widget.TextViewCompat;
 
@@ -24,34 +26,39 @@ import com.bumptech.glide.request.RequestOptions;
 import com.bumptech.glide.request.target.CustomTarget;
 import com.bumptech.glide.request.transition.Transition;
 
-import java.util.Date;
+import java.time.LocalDate;
 import java.util.List;
 
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.ocs.comment.Mention;
 
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.Build.VERSION_CODES.LOLLIPOP;
 import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
+import static java.time.temporal.ChronoUnit.DAYS;
 
 public final class ViewUtil {
     private ViewUtil() {
     }
 
     public static void addAvatar(@NonNull ImageView avatar, @NonNull String baseUrl, @NonNull String userId, @DrawableRes int errorResource) {
-        addAvatar(avatar, baseUrl, userId, DimensionUtil.dpToPx(avatar.getContext(), R.dimen.avatar_size), errorResource);
+        addAvatar(avatar, baseUrl, userId, DimensionUtil.INSTANCE.dpToPx(avatar.getContext(), R.dimen.avatar_size), errorResource);
     }
 
     public static void addAvatar(@NonNull ImageView avatar, @NonNull String baseUrl, @NonNull String userId, @Px int avatarSizeInPx, @DrawableRes int errorResource) {
         final String uri = baseUrl + "/index.php/avatar/" + Uri.encode(userId) + "/" + avatarSizeInPx;
         Glide.with(avatar.getContext())
                 .load(uri)
+                .placeholder(errorResource)
                 .error(errorResource)
                 .apply(RequestOptions.circleCropTransform())
                 .into(avatar);
     }
 
-    public static void themeDueDate(Context context, TextView cardDueDate, Date dueDate) {
-        long diff = DateUtil.getDayDifference(new Date(), dueDate);
+    public static void themeDueDate(@NonNull Context context, @NonNull TextView cardDueDate, @NonNull LocalDate dueDate) {
+        long diff = DAYS.between(LocalDate.now(), dueDate);
 
         int backgroundDrawable = 0;
         int textColor = isDarkTheme(context) ? R.color.dark_fg_primary : R.color.grey600;
@@ -69,21 +76,18 @@ public final class ViewUtil {
         }
 
         cardDueDate.setBackgroundResource(backgroundDrawable);
-        cardDueDate.setTextColor(context.getResources().getColor(textColor));
-        TextViewCompat.setCompoundDrawableTintList(cardDueDate, ColorStateList.valueOf(context.getResources().getColor(textColor)));
+        cardDueDate.setTextColor(ContextCompat.getColor(context, textColor));
+        TextViewCompat.setCompoundDrawableTintList(cardDueDate, ColorStateList.valueOf(ContextCompat.getColor(context, textColor)));
     }
 
-    public static Drawable getTintedImageView(@NonNull Context context, @DrawableRes int imageId, @NonNull String color) {
-        final Drawable drawable = context.getResources().getDrawable(imageId);
+    public static Drawable getTintedImageView(@NonNull Context context, @DrawableRes int imageId, @ColorInt int color) {
+        final Drawable drawable = ContextCompat.getDrawable(context, imageId);
+        assert drawable != null;
         final Drawable wrapped = DrawableCompat.wrap(drawable).mutate();
-        DrawableCompat.setTint(wrapped, Color.parseColor(color));
+        DrawableCompat.setTint(wrapped, color);
         return drawable;
     }
 
-    public static Drawable getTintedImageView(@NonNull Context context, @DrawableRes int imageId, int colorId) {
-        return getTintedImageView(context, imageId, context.getResources().getString(colorId));
-    }
-
     /**
      * Replaces all mentions in the textView with an avatar and the display name
      *
@@ -118,7 +122,7 @@ public final class ViewUtil {
             Glide.with(context)
                     .asBitmap()
                     .placeholder(R.drawable.ic_person_grey600_24dp)
-                    .load(account.getUrl() + "/index.php/avatar/" + messageBuilder.subSequence(spanStart + 1, spanEnd).toString() + "/" + DimensionUtil.dpToPx(context, R.dimen.icon_size_details))
+                    .load(account.getUrl() + "/index.php/avatar/" + messageBuilder.subSequence(spanStart + 1, spanEnd).toString() + "/" + DimensionUtil.INSTANCE.dpToPx(context, R.dimen.icon_size_details))
                     .apply(RequestOptions.circleCropTransform())
                     .into(new CustomTarget<Bitmap>() {
                         @Override
@@ -135,4 +139,12 @@ public final class ViewUtil {
         }
         textView.setText(messageBuilder);
     }
+
+    public static void setImageColor(@NonNull Context context, @NonNull ImageView imageView, @ColorRes int colorRes) {
+        if (SDK_INT >= LOLLIPOP) {
+            imageView.setImageTintList(ColorStateList.valueOf(ContextCompat.getColor(context, colorRes)));
+        } else {
+            imageView.setColorFilter(ContextCompat.getColor(context, colorRes));
+        }
+    }
 }