Merge branch 'master' into 587-compress-images

# Conflicts:
#	app/build.gradle
#	app/src/main/java/it/niedermann/nextcloud/deck/ui/card/attachments/CardAttachmentsFragment.java
#	build.gradle

165 files changed, 5399 insertions, 2163 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 cf30a0971..972c098d6 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/DeckApplication.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/DeckApplication.java
@@ -2,14 +2,20 @@ package it.niedermann.nextcloud.deck;
 
 import android.content.Context;
 import android.content.SharedPreferences;
+import android.content.res.Configuration;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
+import androidx.core.content.ContextCompat;
+import androidx.lifecycle.LiveData;
 import androidx.multidex.MultiDexApplication;
 import androidx.preference.PreferenceManager;
 
-import static androidx.appcompat.app.AppCompatDelegate.MODE_NIGHT_NO;
-import static androidx.appcompat.app.AppCompatDelegate.MODE_NIGHT_YES;
+import it.niedermann.android.sharedpreferences.SharedPreferenceIntLiveData;
+import it.niedermann.nextcloud.deck.model.Account;
+
 import static androidx.appcompat.app.AppCompatDelegate.setDefaultNightMode;
+import static androidx.lifecycle.Transformations.distinctUntilChanged;
 
 public class DeckApplication extends MultiDexApplication {
 
@@ -17,46 +23,112 @@ public class DeckApplication extends MultiDexApplication {
     public static final long NO_BOARD_ID = -1L;
     public static final long NO_STACK_ID = -1L;
 
+    private static String PREF_KEY_THEME;
+    private static String PREF_KEY_DEBUGGING;
+
+    private static LiveData<Integer> currentAccountColor$;
+
     @Override
     public void onCreate() {
-        setAppTheme(isDarkTheme(getApplicationContext()));
+        PREF_KEY_THEME = getString(R.string.pref_key_dark_theme);
+        PREF_KEY_DEBUGGING = getString(R.string.pref_key_debugging);
+        setAppTheme(getAppTheme(this));
+        DeckLog.enablePersistentLogs(isPersistentLoggingEnabled(this));
+        currentAccountColor$ = distinctUntilChanged(new SharedPreferenceIntLiveData(PreferenceManager.getDefaultSharedPreferences(this),
+                getString(R.string.shared_preference_last_account_color),
+                ContextCompat.getColor(this, R.color.defaultBrand)));
         super.onCreate();
     }
 
+    @Override
+    public void onLowMemory() {
+        super.onLowMemory();
+        DeckLog.clearDebugLog();
+        DeckLog.error("--- cleared log because of low memory ---");
+    }
+
+    // ---------
+    // Debugging
+    // ---------
+
+    public static boolean isPersistentLoggingEnabled(@NonNull Context context) {
+        final SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
+        boolean enabled = sharedPreferences.getBoolean(PREF_KEY_DEBUGGING, false);
+        DeckLog.log("--- Read:", PREF_KEY_DEBUGGING, "|", enabled);
+        return enabled;
+    }
+
     // -----------------
     // Day / Night theme
     // -----------------
 
-    public static void setAppTheme(boolean darkTheme) {
-        setDefaultNightMode(darkTheme ? MODE_NIGHT_YES : MODE_NIGHT_NO);
+    public static void setAppTheme(int setting) {
+        setDefaultNightMode(setting);
     }
 
-    public static boolean isDarkTheme(@NonNull Context context) {
+    public static int getAppTheme(@NonNull Context context) {
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
-        return prefs.getBoolean(context.getString(R.string.pref_key_dark_theme), false);
+        String mode;
+        try {
+            mode = prefs.getString(PREF_KEY_THEME, context.getString(R.string.pref_value_theme_system_default));
+        } catch (ClassCastException e) {
+            boolean darkModeEnabled = prefs.getBoolean(PREF_KEY_THEME, false);
+            mode = darkModeEnabled ? context.getString(R.string.pref_value_theme_dark) : context.getString(R.string.pref_value_theme_light);
+        }
+        return Integer.parseInt(mode);
+    }
+
+    public static boolean isDarkThemeActive(@NonNull Context context, int darkModeSetting) {
+        if (darkModeSetting == Integer.parseInt(context.getString(R.string.pref_value_theme_system_default))) {
+            return isDarkThemeActive(context);
+        } else {
+            return darkModeSetting == Integer.parseInt(context.getString(R.string.pref_value_theme_dark));
+        }
+    }
+
+    public static boolean isDarkThemeActive(@NonNull Context context) {
+        int uiMode = context.getResources().getConfiguration().uiMode;
+        return (uiMode & Configuration.UI_MODE_NIGHT_MASK) == Configuration.UI_MODE_NIGHT_YES;
+    }
+
+    public static boolean isDarkTheme(@NonNull Context context) {
+        return isDarkThemeActive(context, getAppTheme(context));
     }
 
     // --------------------------------------
     // Current account / board / stack states
     // --------------------------------------
 
-    public static void saveCurrentAccountId(@NonNull Context context, long accountId) {
+    public static void saveCurrentAccount(@NonNull Context context, @NonNull Account account) {
         SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
-        DeckLog.log("--- Write: shared_preference_last_account" + " | " + accountId);
-        editor.putLong(context.getString(R.string.shared_preference_last_account), accountId);
+        DeckLog.log("--- Write: shared_preference_last_account |", account.getId());
+        editor.putLong(context.getString(R.string.shared_preference_last_account), account.getId());
+        DeckLog.log("--- Write: shared_preference_last_account_color | ", account.getColor());
+        editor.putInt(context.getString(R.string.shared_preference_last_account_color), account.getColor());
         editor.apply();
     }
 
+    public static LiveData<Integer> readCurrentAccountColor() {
+        return currentAccountColor$;
+    }
+
+    @ColorInt
+    public static int readCurrentAccountColor(@NonNull Context context) {
+        final SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context.getApplicationContext());
+        DeckLog.log("--- Read: shared_preference_last_account_color");
+        return sharedPreferences.getInt(context.getString(R.string.shared_preference_last_account_color), context.getApplicationContext().getResources().getColor(R.color.defaultBrand));
+    }
+
     public static long readCurrentAccountId(@NonNull Context context) {
         SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
         long accountId = sharedPreferences.getLong(context.getString(R.string.shared_preference_last_account), NO_ACCOUNT_ID);
-        DeckLog.log("--- Read: shared_preference_last_account" + " | " + accountId);
+        DeckLog.log("--- Read: shared_preference_last_account |", accountId);
         return accountId;
     }
 
     public static void saveCurrentBoardId(@NonNull Context context, long accountId, long boardId) {
         SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
-        DeckLog.log("--- Write: shared_preference_last_board_for_account_" + accountId + " | " + boardId);
+        DeckLog.log("--- Write: shared_preference_last_board_for_account_" + accountId, "|", boardId);
         editor.putLong(context.getString(R.string.shared_preference_last_board_for_account_) + accountId, boardId);
         editor.apply();
     }
@@ -64,13 +136,13 @@ public class DeckApplication extends MultiDexApplication {
     public static long readCurrentBoardId(@NonNull Context context, long accountId) {
         SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
         long boardId = sharedPreferences.getLong(context.getString(R.string.shared_preference_last_board_for_account_) + accountId, NO_BOARD_ID);
-        DeckLog.log("--- Read: shared_preference_last_board_for_account_" + accountId + " | " + boardId);
+        DeckLog.log("--- Read: shared_preference_last_board_for_account_" + accountId, "|", boardId);
         return boardId;
     }
 
     public static void saveCurrentStackId(@NonNull Context context, long accountId, long boardId, long stackId) {
         SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
-        DeckLog.log("--- Write: shared_preference_last_stack_for_account_and_board_" + accountId + "_" + boardId + " | " + stackId);
+        DeckLog.log("--- Write: shared_preference_last_stack_for_account_and_board_" + accountId + "_" + boardId, "|", stackId);
         editor.putLong(context.getString(R.string.shared_preference_last_stack_for_account_and_board_) + accountId + "_" + boardId, stackId);
         editor.apply();
     }
@@ -78,7 +150,7 @@ public class DeckApplication extends MultiDexApplication {
     public static long readCurrentStackId(@NonNull Context context, long accountId, long boardId) {
         SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
         long savedStackId = sharedPreferences.getLong(context.getString(R.string.shared_preference_last_stack_for_account_and_board_) + accountId + "_" + boardId, NO_STACK_ID);
-        DeckLog.log("--- Read: shared_preference_last_stack_for_account_and_board" + accountId + "_" + boardId + " | " + savedStackId);
+        DeckLog.log("--- Read: shared_preference_last_stack_for_account_and_board" + accountId + "_" + boardId, "|", savedStackId);
         return savedStackId;
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/DeckLog.java b/app/src/main/java/it/niedermann/nextcloud/deck/DeckLog.java
index 47a0385e3..e857f0d56 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/DeckLog.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/DeckLog.java
@@ -1,55 +1,74 @@
 package it.niedermann.nextcloud.deck;
 
+import android.content.Context;
+import android.content.Intent;
+import android.text.TextUtils;
 import android.util.Log;
+import android.widget.Toast;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.core.content.FileProvider;
 
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
 import java.io.PrintWriter;
 import java.io.StringWriter;
 
+import it.niedermann.nextcloud.deck.util.MimeTypeUtil;
+
 public class DeckLog {
+
+    private static final StringBuffer DEBUG_LOG = new StringBuffer();
+    private static boolean PERSIST_LOGS = false;
     private static final String TAG = DeckLog.class.getSimpleName();
 
+    public static void enablePersistentLogs(boolean persistLogs) {
+        PERSIST_LOGS = persistLogs;
+        if (!persistLogs) {
+            clearDebugLog();
+        }
+    }
+
     public enum Severity {
         VERBOSE, DEBUG, LOG, INFO, WARN, ERROR
     }
 
-    public static void verbose(String message) {
-        log(message, Severity.VERBOSE, 4);
+    public static void verbose(Object... message) {
+        log(Severity.VERBOSE, 4, message);
     }
 
-    public static void log(String message) {
-        log(message, Severity.DEBUG, 4);
+    public static void log(Object... message) {
+        log(Severity.DEBUG, 4, message);
     }
 
-    public static void info(String message) {
-        log(message, Severity.INFO, 4);
+    public static void info(Object... message) {
+        log(Severity.INFO, 4, message);
     }
 
-    public static void warn(String message) {
-        log(message, Severity.WARN, 4);
+    public static void warn(Object... message) {
+        log(Severity.WARN, 4, message);
     }
 
-    public static void error(String message) {
-        log(message, Severity.ERROR, 4);
+    public static void error(Object... message) {
+        log(Severity.ERROR, 4, message);
     }
 
-    public static void log(String message, Severity severity) {
-        log(message, severity, 3);
+    public static void log(@NonNull Severity severity, Object... message) {
+        log(severity, 3, message);
     }
 
-    private static void log(String message, Severity severity, int stackTracePosition) {
-        final String print;
-        if (BuildConfig.DEBUG) {
-            final StackTraceElement caller = Thread.currentThread().getStackTrace()[stackTracePosition];
-            print = caller.getMethodName() + "() (" + caller.getFileName() + ":" + caller.getLineNumber() + ") → " + message;
-        } else {
-            print = message;
+    private static void log(@NonNull Severity severity, int stackTracePosition, Object... messages) {
+        if (!(PERSIST_LOGS || BuildConfig.DEBUG)) {
+            return;
+        }
+        final StackTraceElement caller = Thread.currentThread().getStackTrace()[stackTracePosition];
+        final String print = "(" + caller.getFileName() + ":" + caller.getLineNumber() + ") " + caller.getMethodName() + "() → " + TextUtils.join(" ", messages);
+        if (PERSIST_LOGS) {
+            DEBUG_LOG.append(print).append("\n");
         }
         switch (severity) {
-            case VERBOSE:
-                Log.v(TAG, print);
-                break;
             case DEBUG:
                 Log.d(TAG, print);
                 break;
@@ -69,41 +88,46 @@ public class DeckLog {
     }
 
     public static void logError(@Nullable Throwable e) {
+        if (!(PERSIST_LOGS || BuildConfig.DEBUG)) {
+            return;
+        }
         if (e == null) {
             error("Could not log error because given error was null");
             return;
         }
         final StringWriter sw = new StringWriter();
         e.printStackTrace(new PrintWriter(sw));
-        String stacktrace = sw.toString(); // stack trace as a string
+        final String stacktrace = sw.toString();
         final StackTraceElement caller = Thread.currentThread().getStackTrace()[3];
-        final String source = caller.getMethodName() + "() (" + caller.getFileName() + ":" + caller.getLineNumber() + ") -> ";
-        Log.e(TAG, source + stacktrace);
+        final String print = "(" + caller.getFileName() + ":" + caller.getLineNumber() + ") " + caller.getMethodName() + "() → " + stacktrace;
+        if (PERSIST_LOGS) {
+            DEBUG_LOG.append(print).append("\n");
+        }
+        Log.e(TAG, print);
     }
 
-    public static void printCurrentStacktrace() {
-        log(getCurrentStacktrace(4));
+    @NonNull
+    public static String getDebugLog() {
+        return DEBUG_LOG.toString();
     }
 
-    public static String getCurrentStacktrace() {
-        return getCurrentStacktrace(4);
+    public static void clearDebugLog() {
+        DEBUG_LOG.setLength(0);
     }
 
-    private static String getCurrentStacktrace(@SuppressWarnings("SameParameterValue") int offset) {
-        final StackTraceElement[] elements = Thread.currentThread().getStackTrace();
-        final StringBuilder buff = new StringBuilder();
-        for (int i = offset; i < elements.length; i++) {
-            final StackTraceElement s = elements[i];
-            buff.append("\tat ");
-            buff.append(s.getClassName());
-            buff.append(".");
-            buff.append(s.getMethodName());
-            buff.append("(");
-            buff.append(s.getFileName());
-            buff.append(":");
-            buff.append(s.getLineNumber());
-            buff.append(")\n");
-        }
-        return buff.toString();
+    /**
+     * Writes the current log to a temporary file and starts a share intent.
+     */
+    public static void shareLogAsFile(@NonNull Context context) throws IOException {
+        Toast.makeText(context, R.string.copying_logs_to_file, Toast.LENGTH_LONG).show();
+        final File logFile = new File(context.getCacheDir().getAbsolutePath() + "/log.txt");
+        final FileWriter writer = new FileWriter(logFile);
+        writer.write(DeckLog.getDebugLog());
+        writer.close();
+        context.startActivity(new Intent(Intent.ACTION_SEND)
+                .putExtra(Intent.EXTRA_TITLE, context.getString(R.string.log_file))
+                .putExtra(Intent.EXTRA_STREAM, FileProvider.getUriForFile(context, BuildConfig.APPLICATION_ID + ".provider", logFile))
+                .setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+                .setType(MimeTypeUtil.TEXT_PLAIN));
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/ApiProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/ApiProvider.java
index e2cfda22e..a6e8da168 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/ApiProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/ApiProvider.java
@@ -18,19 +18,18 @@ import retrofit2.NextcloudRetrofitApiBuilder;
 /**
  * Created by david on 26.05.17.
  */
-
 public class ApiProvider {
 
-    private static final String DECK_API_ENDPOINT = "/index.php/apps/deck/api/v1.0/";
+    private static final String DECK_API_ENDPOINT = "/index.php/apps/deck/api/";
     private static final String NC_API_ENDPOINT = "/ocs/v2.php/";
 
     private DeckAPI deckAPI;
     private NextcloudServerAPI nextcloudAPI;
     @NonNull
-    private Context context;
-    private SingleSignOnAccount ssoAccount;
+    private final Context context;
     @Nullable
-    private String ssoAccountName;
+    private final String ssoAccountName;
+    private SingleSignOnAccount ssoAccount;
 
     public ApiProvider(Context context) {
         this(context, null);
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 1f0148b91..9e1b7d7f4 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
@@ -12,6 +12,7 @@ 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.enums.EAttachmentType;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
 import it.niedermann.nextcloud.deck.model.full.FullStack;
@@ -32,129 +33,148 @@ import retrofit2.http.Part;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
+/**
+ * @link <a href="https://deck.readthedocs.io/en/latest/API/">Deck REST API</a>
+ */
 public interface DeckAPI {
 
     String MODIFIED_SINCE_HEADER = "If-Modified-Since";
     String IF_NONE_MATCH = "If-None-Match";
 
-    // ### BOARDS
-    @POST("boards")
+
+    // Boards
+
+    @POST("v1.0/boards")
     Observable<FullBoard> createBoard(@Body Board board);
 
-    @GET("boards/{id}")
+    @GET("v1.0/boards/{id}")
     Observable<FullBoard> getBoard(@Path("id") long id, @Header(MODIFIED_SINCE_HEADER) String lastSync);
 
-    @PUT("boards/{id}")
+    @PUT("v1.0/boards/{id}")
     Observable<FullBoard> updateBoard(@Path("id") long id, @Body Board board);
 
-    @DELETE("boards/{id}")
+    @DELETE("v1.0/boards/{id}")
     Observable<Void> deleteBoard(@Path("id") long id);
 
-    @DELETE("boards/{id}/undo_delete")
+    @DELETE("v1.0/boards/{id}/undo_delete")
     Observable<FullBoard> restoreBoard(@Path("id") long id);
 
-    @GET("boards")
-    Observable<ParsedResponse<List<FullBoard>>> getBoards(@Query ("details") boolean verbose, @Header(MODIFIED_SINCE_HEADER) String lastSync, @Header(IF_NONE_MATCH) String eTag);
+    @GET("v1.0/boards")
+    Observable<ParsedResponse<List<FullBoard>>> getBoards(@Query("details") boolean verbose, @Header(MODIFIED_SINCE_HEADER) String lastSync, @Header(IF_NONE_MATCH) String eTag);
+
+    @GET("v1.0/boards")
+    Observable<ParsedResponse<List<FullBoard>>> getBoards(@Query("details") boolean verbose, @Header(MODIFIED_SINCE_HEADER) String lastSync);
 
 
-    // ### Stacks
-    @POST("boards/{boardId}/stacks")
-    Observable<FullStack>  createStack(@Path("boardId") long boardId, @Body Stack stack);
+    // Stacks
 
-    @PUT("boards/{boardId}/stacks/{stackId}")
+    @POST("v1.0/boards/{boardId}/stacks")
+    Observable<FullStack> createStack(@Path("boardId") long boardId, @Body Stack stack);
+
+    @PUT("v1.0/boards/{boardId}/stacks/{stackId}")
     Observable<FullStack> updateStack(@Path("boardId") long boardId, @Path("stackId") long id, @Body Stack stack);
 
-    @DELETE("boards/{boardId}/stacks/{stackId}")
+    @DELETE("v1.0/boards/{boardId}/stacks/{stackId}")
     Observable<Void> deleteStack(@Path("boardId") long boardId, @Path("stackId") long id);
 
-    @GET("boards/{boardId}/stacks/{stackId}")
+    @GET("v1.0/boards/{boardId}/stacks/{stackId}")
     Observable<FullStack> getStack(@Path("boardId") long boardId, @Path("stackId") long id, @Header(MODIFIED_SINCE_HEADER) String lastSync);
 
-    @GET("boards/{boardId}/stacks")
+    @GET("v1.0/boards/{boardId}/stacks")
     Observable<List<FullStack>> getStacks(@Path("boardId") long boardId, @Header(MODIFIED_SINCE_HEADER) String lastSync);
 
-    @GET("boards/{boardId}/stacks/archived")
+    @GET("v1.0/boards/{boardId}/stacks/archived")
     Observable<List<Stack>> getArchivedStacks(@Path("boardId") long boardId, @Header(MODIFIED_SINCE_HEADER) String lastSync);
 
 
-    // ### Cards
-    @POST("boards/{boardId}/stacks/{stackId}/cards")
+    // Cards
+
+    @POST("v1.0/boards/{boardId}/stacks/{stackId}/cards")
     Observable<FullCard> createCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Body Card card);
 
-    @PUT("boards/{boardId}/stacks/{stackId}/cards/{cardId}")
+    @PUT("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}")
     Observable<FullCard> updateCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Body CardUpdate card);
 
     @FormUrlEncoded
-    @PUT("boards/{boardId}/stacks/{stackId}/cards/{cardId}/assignLabel")
+    @PUT("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/assignLabel")
     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")
+    @PUT("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/removeLabel")
     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")
+    @PUT("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/assignUser")
     Observable<Void> assignUserToCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Field("userId") String userUID);
 
     @FormUrlEncoded
-    @PUT("boards/{boardId}/stacks/{stackId}/cards/{cardId}/unassignUser")
-    Observable<Void> unassignUserFromCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Field("userId")  String userUID);
+    @PUT("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/unassignUser")
+    Observable<Void> unassignUserFromCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Field("userId") String userUID);
 
-    @PUT("boards/{boardId}/stacks/{stackId}/cards/{cardId}/reorder")
+    @PUT("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/reorder")
     Observable<List<FullCard>> moveCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Body Reorder reorder);
 
-    @DELETE("boards/{boardId}/stacks/{stackId}/cards/{cardId}")
+    @DELETE("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}")
     Observable<Void> deleteCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId);
 
-    @GET("boards/{boardId}/stacks/{stackId}/cards/{cardId}")
-    Observable<FullCard> getCard(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Header(MODIFIED_SINCE_HEADER) String lastSync);
+    /**
+     * @see <a href="https://github.com/nextcloud/deck/issues/2874">This endpoint does only return {@link Attachment}s of type {@link EAttachmentType.DECK_FILE}</a>
+     */
+    @SuppressWarnings("JavadocReference")
+    @GET("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}")
+    Observable<FullCard> getCard_1_0(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Header(MODIFIED_SINCE_HEADER) String lastSync);
+
+    @GET("v1.1/boards/{boardId}/stacks/{stackId}/cards/{cardId}")
+    Observable<FullCard> getCard_1_1(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Header(MODIFIED_SINCE_HEADER) String lastSync);
 
 
-    // ### LABELS
-    @GET("boards/{boardId}/labels/{labelId}")
+    // Labels
+
+    @GET("v1.0/boards/{boardId}/labels/{labelId}")
     Observable<Label> getLabel(@Path("boardId") long boardId, @Path("labelId") long labelId, @Header(MODIFIED_SINCE_HEADER) String lastSync);
 
-    @PUT("boards/{boardId}/labels/{labelId}")
+    @PUT("v1.0/boards/{boardId}/labels/{labelId}")
     Observable<Label> updateLabel(@Path("boardId") long boardId, @Path("labelId") long labelId, @Body Label label);
 
-    @POST("boards/{boardId}/labels")
+    @POST("v1.0/boards/{boardId}/labels")
     Observable<Label> createLabel(@Path("boardId") long boardId, @Body Label label);
 
-    @DELETE("boards/{boardId}/labels/{labelId}")
+    @DELETE("v1.0/boards/{boardId}/labels/{labelId}")
     Observable<Void> deleteLabel(@Path("boardId") long boardId, @Path("labelId") long labelId);
 
 
-    // ### ATTACHMENTS
-    @GET("boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments/{attachmentId}")
+    // Attachments
+
+    @GET("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments/{attachmentId}")
     Observable<ResponseBody> downloadAttachment(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Path("attachmentId") long attachmentId);
 
-    @GET("boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments")
+    @GET("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments")
     Observable<List<Attachment>> getAttachments(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId);
 
     @Multipart
-    @POST("boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments?type=deck_file")
-    Observable<Attachment> uploadAttachment(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId,  @Part MultipartBody.Part type, @Part MultipartBody.Part attachment);
+    @POST("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments")
+    Observable<Attachment> uploadAttachment(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Part MultipartBody.Part type, @Part MultipartBody.Part attachment);
 
     @Multipart
-    @PUT("boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments?type=deck_file")
-    Observable<Attachment>  updateAttachment(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Path("attachmentId") long attachmentId, @Part MultipartBody.Part type, @Part MultipartBody.Part attachment);
+    @PUT("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments")
+    Observable<Attachment> updateAttachment(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Path("attachmentId") long attachmentId, @Part MultipartBody.Part type, @Part MultipartBody.Part attachment);
 
-    @DELETE("boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments/{attachmentId}")
+    @DELETE("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments/{attachmentId}")
     Observable<Void> deleteAttachment(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Path("attachmentId") long attachmentId);
 
-    @PUT("boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments/{attachmentId}/restore")
+    @PUT("v1.0/boards/{boardId}/stacks/{stackId}/cards/{cardId}/attachments/{attachmentId}/restore")
     Observable<Attachment> restoreAttachment(@Path("boardId") long boardId, @Path("stackId") long stackId, @Path("cardId") long cardId, @Path("attachmentId") long attachmentId);
 
-    // ### ACL
-    @POST("boards/{boardId}/acl")
+
+    // Access control lists
+
+    @POST("v1.0/boards/{boardId}/acl")
     Observable<AccessControl> createAccessControl(@Path("boardId") long boardId, @Body AccessControl acl);
 
-    @PUT("boards/{boardId}/acl/{aclId}")
+    @PUT("v1.0/boards/{boardId}/acl/{aclId}")
     Observable<AccessControl> updateAccessControl(@Path("boardId") long boardId, @Path("aclId") long aclId, @Body AccessControl acl);
 
-    @DELETE("boards/{boardId}/acl/{aclId}")
+    @DELETE("v1.0/boards/{boardId}/acl/{aclId}")
     Observable<Void> deleteAccessControl(@Path("boardId") long boardId, @Path("aclId") long aclId, @Body AccessControl acl);
 
-    // ### COMMENTS
-
 }
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 be3eaeb22..3134d45aa 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
@@ -1,44 +1,24 @@
 package it.niedermann.nextcloud.deck.api;
 
-import androidx.annotation.CallSuper;
+import android.annotation.SuppressLint;
+
+import androidx.annotation.NonNull;
 
 import java.util.Collection;
 import java.util.List;
 
-import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
 
 
-public abstract class IResponseCallback<T> {
+public abstract class IResponseCallback<T> implements ResponseCallback<T> {
+    @NonNull
     protected Account account;
 
-    public IResponseCallback(Account account) {
+    public IResponseCallback(@NonNull Account account) {
         this.account = account;
     }
 
-    public abstract void onResponse(T response);
-
-    @CallSuper
-    public void onError(Throwable throwable) {
-        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
-            }
-
-        };
-    }
-
     public void fillAccountIDs(T response) {
         if (response != null) {
             if (isListOfRemoteEntity(response)) {
@@ -71,7 +51,26 @@ public abstract class IResponseCallback<T> {
         return false;
     }
 
+    @NonNull
     public Account getAccount() {
         return account;
     }
+
+    /**
+     * Forwards responses and errors to the given {@param callback}
+     */
+    public static <T> IResponseCallback<T> from(@NonNull Account account, ResponseCallback<T> callback) {
+        return new IResponseCallback<T>(account) {
+            @Override
+            public void onResponse(T response) {
+                callback.onResponse(response);
+            }
+
+            @SuppressLint("MissingSuperCall")
+            @Override
+            public void onError(Throwable throwable) {
+                callback.onError(throwable);
+            }
+        };
+    }
 }
\ No newline at end of file
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 e759f27d4..2443a919c 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
@@ -23,6 +23,7 @@ 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.ActivityType;
+import it.niedermann.nextcloud.deck.model.enums.EAttachmentType;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
 import it.niedermann.nextcloud.deck.model.full.FullStack;
@@ -75,7 +76,7 @@ public class JsonToEntityParser {
     }
 
     private static GroupMemberUIDs parseGroupMemberUIDs(JsonObject obj) {
-        DeckLog.verbose(obj.toString());
+        DeckLog.verbose(obj);
         GroupMemberUIDs uids = new GroupMemberUIDs();
         makeTraceableIfFails(() -> {
             JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
@@ -93,7 +94,7 @@ public class JsonToEntityParser {
     }
 
     private static OcsUserList parseOcsUserList(JsonObject obj) {
-        DeckLog.verbose(obj.toString());
+        DeckLog.verbose(obj);
         OcsUserList ocsUserList = new OcsUserList();
         makeTraceableIfFails(() -> {
             JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
@@ -118,7 +119,7 @@ public class JsonToEntityParser {
     }
 
     private static OcsUser parseSingleOcsUser(JsonObject obj) {
-        DeckLog.verbose(obj.toString());
+        DeckLog.verbose(obj);
         OcsUser ocsUser = new OcsUser();
         makeTraceableIfFails(() -> {
             JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
@@ -137,7 +138,7 @@ public class JsonToEntityParser {
     }
 
     private static OcsProjectList parseOcsProjectList(JsonObject obj) {
-        DeckLog.verbose(obj.toString());
+        DeckLog.verbose(obj);
         OcsProjectList projectList = new OcsProjectList();
         makeTraceableIfFails(() -> {
             JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
@@ -171,7 +172,7 @@ public class JsonToEntityParser {
     }
 
     private static OcsProjectResource parseOcsProjectResource(JsonObject obj) {
-        DeckLog.verbose(obj.toString());
+        DeckLog.verbose(obj);
         OcsProjectResource resource = new OcsProjectResource();
         makeTraceableIfFails(() -> {
             if (obj.has("id")) {
@@ -213,7 +214,7 @@ public class JsonToEntityParser {
     }
 
     private static OcsComment parseOcsComment(JsonObject obj) {
-        DeckLog.verbose(obj.toString());
+        DeckLog.verbose(obj);
         OcsComment comment = new OcsComment();
         makeTraceableIfFails(() -> {
             JsonElement data = obj.get("ocs").getAsJsonObject().get("data");
@@ -229,7 +230,7 @@ public class JsonToEntityParser {
     }
 
     private static DeckComment parseDeckComment(JsonElement data) {
-        DeckLog.verbose(data.toString());
+        DeckLog.verbose(data);
         DeckComment deckComment = new DeckComment();
 
         makeTraceableIfFails(() -> {
@@ -261,7 +262,7 @@ public class JsonToEntityParser {
 
     private static Mention parseMention(JsonElement mentionJson) {
         Mention mention = new Mention();
-        DeckLog.verbose(mentionJson.toString());
+        DeckLog.verbose(mentionJson);
 
 
         makeTraceableIfFails(() -> {
@@ -278,7 +279,7 @@ public class JsonToEntityParser {
     protected static FullBoard parseBoard(JsonObject e) {
         FullBoard fullBoard = new FullBoard();
 
-        DeckLog.verbose(e.toString());
+        DeckLog.verbose(e);
         Board board = new Board();
 
         makeTraceableIfFails(() -> {
@@ -364,7 +365,7 @@ public class JsonToEntityParser {
     }
 
     protected static AccessControl parseAcl(JsonObject aclJson) {
-        DeckLog.verbose(aclJson.toString());
+        DeckLog.verbose(aclJson);
         AccessControl acl = new AccessControl();
 
         if (aclJson.has("participant") && !aclJson.get("participant").isJsonNull()) {
@@ -387,7 +388,7 @@ public class JsonToEntityParser {
     }
 
     protected static FullCard parseCard(JsonObject e) {
-        DeckLog.verbose(e.toString());
+        DeckLog.verbose(e);
         FullCard fullCard = new FullCard();
         Card card = new Card();
         fullCard.setCard(card);
@@ -452,12 +453,12 @@ public class JsonToEntityParser {
     }
 
     protected static Attachment parseAttachment(JsonObject e) {
-        DeckLog.verbose(e.toString());
+        DeckLog.verbose(e);
         Attachment a = new Attachment();
         makeTraceableIfFails(() -> {
             a.setId(e.get("id").getAsLong());
             a.setCardId(e.get("cardId").getAsLong());
-            a.setType(e.get("type").getAsString());
+            a.setType(EAttachmentType.findByValue(e.get("type").getAsString()));
             a.setEtag(getNullAsNull(e.get("ETag")));
             a.setData(e.get("data").getAsString());
             a.setLastModified(getTimestampFromLong(e.get("lastModified")));
@@ -468,6 +469,9 @@ public class JsonToEntityParser {
                 JsonObject extendedData = e.getAsJsonObject("extendedData").getAsJsonObject();
                 a.setFilesize(extendedData.get("filesize").getAsLong());
                 a.setMimetype(extendedData.get("mimetype").getAsString());
+                if (extendedData.has("fileid") && !extendedData.get("fileid").isJsonNull()) {
+                    a.setFileId(extendedData.get("fileid").getAsLong());
+                }
                 if (extendedData.has("info") && !extendedData.get("info").isJsonNull()) {
                     JsonObject info = extendedData.getAsJsonObject("info").getAsJsonObject();
                     a.setDirname(info.get("dirname").getAsString());
@@ -484,7 +488,7 @@ public class JsonToEntityParser {
     }
 
     protected static User parseUser(JsonElement userElement) {
-        DeckLog.verbose(userElement.toString());
+        DeckLog.verbose(userElement);
         if (userElement.isJsonNull()) {
             return null;
         }
@@ -509,7 +513,7 @@ public class JsonToEntityParser {
 
 
     protected static Capabilities parseCapabilities(JsonObject e) {
-        DeckLog.verbose(e.toString());
+        DeckLog.verbose(e);
         Capabilities capabilities = new Capabilities();
         // not traceable, we need the original DeckException for error handling
         if (e.has("ocs")) {
@@ -575,7 +579,7 @@ public class JsonToEntityParser {
     }
 
     protected static FullStack parseStack(JsonObject e) {
-        DeckLog.verbose(e.toString());
+        DeckLog.verbose(e);
         FullStack fullStack = new FullStack();
         Stack stack = new Stack();
         fullStack.setStack(stack);
@@ -605,7 +609,7 @@ public class JsonToEntityParser {
     }
 
     protected static List<Activity> parseActivity(JsonObject e) {
-        DeckLog.verbose(e.toString());
+        DeckLog.verbose(e);
         List<Activity> activityList = new ArrayList<>();
 
         makeTraceableIfFails(() -> {
@@ -633,7 +637,7 @@ public class JsonToEntityParser {
     }
 
     protected static Label parseLabel(JsonObject e) {
-        DeckLog.verbose(e.toString());
+        DeckLog.verbose(e);
         Label label = new Label();
         makeTraceableIfFails(() -> {
             label.setId(e.get("id").getAsLong());
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudArrayDeserializer.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudArrayDeserializer.java
index 820cfc653..1e99c8817 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudArrayDeserializer.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudArrayDeserializer.java
@@ -35,8 +35,14 @@ public class NextcloudArrayDeserializer<T> implements JsonDeserializer<List<T>>
                 JsonObject obj = jArr.get(i).getAsJsonObject();
                 items.add(JsonToEntityParser.parseJsonObject(obj, mType));
             }
+        } else if (json.isJsonObject()) {
+            try {
+                items.add(JsonToEntityParser.parseJsonObject(json.getAsJsonObject(), mType));
+            } catch (Exception e) {
+                throw new IllegalArgumentException("NextcloudArrayDeserializer got a Json Object, fallback parsing failed for input: " + json);
+            }
         } else {
-            throw new IllegalArgumentException("NextcloudArrayDeserializer got an non-array Json Object: " + json);
+            throw new IllegalArgumentException("NextcloudArrayDeserializer got a malformed Json Object: " + json);
         }
         return items;
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudDeserializer.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudDeserializer.java
index d23807957..0b84036a4 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudDeserializer.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/NextcloudDeserializer.java
@@ -26,7 +26,7 @@ public class NextcloudDeserializer<T> implements JsonDeserializer<T> {
 
     @Override
     public T deserialize(final JsonElement json, final Type typeOfT, final JsonDeserializationContext context) throws JsonParseException {
-        DeckLog.verbose(json.toString());
+        DeckLog.verbose(json);
         return JsonToEntityParser.parseJsonObject(json.getAsJsonObject(), mType);
 
     }
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 7b93ace49..54e573d73 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
@@ -24,14 +24,27 @@ import retrofit2.http.PUT;
 import retrofit2.http.Path;
 import retrofit2.http.Query;
 
+
+/**
+ * @link <a href="https://deck.readthedocs.io/en/latest/API-Nextcloud/">Nextcloud REST API</a>
+ */
 public interface NextcloudServerAPI {
 
+
+    // Capabilities
+
     @GET("cloud/capabilities?format=json")
     Observable<ParsedResponse<Capabilities>> getCapabilities(@Header("If-None-Match") String eTag);
 
+
+    // Projects
+
     @GET("collaboration/resources/deck-card/{cardId}?format=json")
     Observable<OcsProjectList> getProjectsForCard(@Path("cardId") long cardId);
 
+
+    // Users
+
     @GET("apps/files_sharing/api/v1/sharees?format=json&perPage=20&itemType=0%2C1%2C7")
     Observable<OcsUserList> searchUser(@Query("search") String searchTerm);
 
@@ -41,9 +54,15 @@ public interface NextcloudServerAPI {
     @GET("cloud/users/{search}?format=json")
     Observable<OcsUser> getSingleUserData(@Path("search") String userUid);
 
+
+    // Activities
+
     @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);
 
+
+    // Comments
+
     @Headers({
             "Accept: application/json",
             "Content-Type: application/json;charset=utf-8"
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/api/ResponseCallback.java b/app/src/main/java/it/niedermann/nextcloud/deck/api/ResponseCallback.java
new file mode 100644
index 000000000..93b2bcc0d
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/api/ResponseCallback.java
@@ -0,0 +1,23 @@
+package it.niedermann.nextcloud.deck.api;
+
+import androidx.annotation.CallSuper;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+
+public interface ResponseCallback<T> {
+
+    void onResponse(T response);
+
+    @CallSuper
+    default void onError(Throwable throwable) {
+        DeckLog.logError(throwable);
+    }
+
+    /**
+     * @return a default {@link ResponseCallback} which does nothing {@link #onResponse(Object)} and the default action fo {@link #onError(Throwable)}
+     */
+    static <T> ResponseCallback<T> empty() {
+        return response -> {
+        };
+    }
+}
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 7eabcbe70..eaa50dfa1 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
@@ -1,13 +1,14 @@
 package it.niedermann.nextcloud.deck.model;
 
+import androidx.annotation.Nullable;
 import androidx.room.Entity;
 import androidx.room.ForeignKey;
-import androidx.room.Ignore;
 import androidx.room.Index;
 
 import java.io.Serializable;
 import java.time.Instant;
 
+import it.niedermann.nextcloud.deck.model.enums.EAttachmentType;
 import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
 
 @Entity(inheritSuperIndices = true,
@@ -24,7 +25,8 @@ import it.niedermann.nextcloud.deck.model.interfaces.AbstractRemoteEntity;
 public class Attachment extends AbstractRemoteEntity implements Comparable<Attachment>, Serializable {
 
     private long cardId;
-    private String type = "deck_file";
+    // TODO use EAttachmentType
+    private EAttachmentType type = EAttachmentType.DECK_FILE;
     private String data;
     private Instant createdAt;
     private String createdBy;
@@ -36,9 +38,8 @@ 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;
+    @Nullable
+    private Long fileId;
 
     public long getCardId() {
         return cardId;
@@ -48,11 +49,11 @@ public class Attachment extends AbstractRemoteEntity implements Comparable<Attac
         this.cardId = cardId;
     }
 
-    public String getType() {
+    public EAttachmentType getType() {
         return type;
     }
 
-    public void setType(String type) {
+    public void setType(EAttachmentType type) {
         this.type = type;
     }
 
@@ -144,19 +145,12 @@ 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() {
+    @Nullable
+    public Long getFileId() {
         return this.fileId;
     }
 
-    /**
-     * TODO depends on https://github.com/nextcloud/deck/pull/2638
-     */
-    @Ignore
-    public void setFileId(String fileId) {
+    public void setFileId(@Nullable Long fileId) {
         this.fileId = fileId;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/ActivityType.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/ActivityType.java
index afaeee69c..8b4246bf2 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/ActivityType.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/ActivityType.java
@@ -43,7 +43,7 @@ public enum ActivityType {
                 return s;
             }
         }
-        DeckLog.error("unknown ActivityType path: " + id);
+        DeckLog.error("unknown ActivityType path:", id);
         return CHANGE;
     }
 
@@ -56,7 +56,7 @@ public enum ActivityType {
                 return s;
             }
         }
-        DeckLog.error("unknown ActivityType path: " + path);
+        DeckLog.error("unknown ActivityType path:", path);
         return CHANGE;
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/EAttachmentType.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/EAttachmentType.java
new file mode 100644
index 000000000..92c15d6e0
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/EAttachmentType.java
@@ -0,0 +1,33 @@
+package it.niedermann.nextcloud.deck.model.enums;
+
+public enum EAttachmentType {
+    // Do not change values. They match the Deck server apps values.
+    DECK_FILE(1, "deck_file"),
+    FILE(2, "file"),
+    UNKNOWN(1337, "unknown");
+
+    private final int id;
+    private final String value;
+
+    EAttachmentType(int id, String value) {
+        this.id = id;
+        this.value = value;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public static EAttachmentType findByValue(String value) {
+        for (EAttachmentType s : EAttachmentType.values()) {
+            if (s.value.equals(value)) {
+                return s;
+            }
+        }
+        return UNKNOWN;
+    }
+
+    public String getValue() {
+        return value;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/EDueType.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/EDueType.java
index 5241ae763..da9193635 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/EDueType.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/EDueType.java
@@ -8,17 +8,32 @@ import androidx.annotation.StringRes;
 import it.niedermann.nextcloud.deck.R;
 
 public enum EDueType {
-    NO_FILTER(R.string.filter_no_filter),
-    OVERDUE(R.string.filter_overdue),
-    TODAY(R.string.filter_today),
-    WEEK(R.string.filter_week),
-    MONTH(R.string.filter_month),
-    NO_DUE(R.string.filter_no_due);
+    NO_FILTER(1, R.string.filter_no_filter),
+    OVERDUE(2, R.string.filter_overdue),
+    TODAY(3, R.string.filter_today),
+    WEEK(4, R.string.filter_week),
+    MONTH(5, R.string.filter_month),
+    NO_DUE(6, R.string.filter_no_due);
 
-    private int value;
+    private final int value;
+    private final int id;
 
-    EDueType(@StringRes int value) {
+    EDueType(int id, @StringRes int value) {
         this.value = value;
+        this.id = id;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public static EDueType findById(int id) {
+        for (EDueType s : EDueType.values()) {
+            if (s.getId() == id) {
+                return s;
+            }
+        }
+        throw new IllegalArgumentException("unknown " + EDueType.class.getSimpleName() + " key: " + id);
     }
 
     @NonNull
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/ESortCriteria.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/ESortCriteria.java
new file mode 100644
index 000000000..5b1343302
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/enums/ESortCriteria.java
@@ -0,0 +1,35 @@
+package it.niedermann.nextcloud.deck.model.enums;
+
+public enum ESortCriteria {
+    /**
+     * Account → Board → Stack
+     */
+    LOCATION(1),
+    /**
+     * Modification date of the card including comments, attachments etc.
+     */
+    MODIFIED(2),
+    LAST_COMMENTED(3),
+    DUE_DATE(4),
+    ASSIGNEE(5),
+    LABEL(6);
+
+    private final int id;
+
+    ESortCriteria(int id) {
+        this.id = id;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public static ESortCriteria findById(int id) {
+        for (ESortCriteria s : ESortCriteria.values()) {
+            if (s.getId() == id) {
+                return s;
+            }
+        }
+        throw new IllegalArgumentException("unknown " + ESortCriteria.class.getSimpleName() + " key: " + id);
+    }
+}
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 611baf3df..dc4cf1fef 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
@@ -110,7 +110,7 @@ public class FullCard implements IRemoteEntity, DragAndDropModel {
     }
 
     public List<Attachment> getAttachments() {
-        if (!isAttachmentsSorted) {
+        if (!isAttachmentsSorted && attachments != null) {
             Collections.sort(attachments);
             isAttachmentsSorted = true;
         }
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 1b5f0879d..81aa8cd80 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
@@ -10,6 +10,7 @@ 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.ocs.projects.OcsProject;
 
 public class FilterInformation implements Serializable {
 
@@ -21,11 +22,14 @@ public class FilterInformation implements Serializable {
     private EDueType dueType = EDueType.NO_FILTER;
     private boolean noAssignedLabel = false;
     private boolean noAssignedUser = false;
+    private boolean noAssignedProject = false;
     @NonNull
     private List<User> users = new ArrayList<>();
     @NonNull
     private List<Label> labels = new ArrayList<>();
     @NonNull
+    private List<OcsProject> projects = new ArrayList<>();
+    @NonNull
     private EArchiveStatus archiveStatus = EArchiveStatus.NON_ARCHIVED;
 
     public FilterInformation() {
@@ -41,6 +45,8 @@ public class FilterInformation implements Serializable {
             this.noAssignedUser = filterInformation.isNoAssignedUser();
             this.noAssignedLabel = filterInformation.isNoAssignedLabel();
             this.archiveStatus = filterInformation.getArchiveStatus();
+            this.noAssignedProject = filterInformation.isNoAssignedProject();
+            this.projects = filterInformation.getProjects();
         }
     }
 
@@ -99,6 +105,31 @@ public class FilterInformation implements Serializable {
         this.archiveStatus = archiveStatus;
     }
 
+    public void setUsers(@NonNull List<User> users) {
+        this.users = users;
+    }
+
+    public boolean isNoAssignedProject() {
+        return noAssignedProject;
+    }
+
+    public void setNoAssignedProject(boolean noAssignedProject) {
+        this.noAssignedProject = noAssignedProject;
+    }
+
+    public void setLabels(@NonNull List<Label> labels) {
+        this.labels = labels;
+    }
+
+    @NonNull
+    public List<OcsProject> getProjects() {
+        return projects;
+    }
+
+    public void setProjects(@NonNull List<OcsProject> projects) {
+        this.projects = projects;
+    }
+
     @NonNull
     public EArchiveStatus getArchiveStatus() {
         return archiveStatus;
@@ -126,8 +157,10 @@ public class FilterInformation implements Serializable {
         }
         return filterInformation.getDueType() != EDueType.NO_FILTER
                 || filterInformation.getUsers().size() > 0
+                || filterInformation.getProjects().size() > 0
                 || filterInformation.getLabels().size() > 0
                 || filterInformation.noAssignedUser
+                || filterInformation.noAssignedProject
                 || filterInformation.noAssignedLabel;
     }
 }
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 cfd973831..91817b73e 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
@@ -1,9 +1,6 @@
 package it.niedermann.nextcloud.deck.model.ocs;
 
-import android.content.Context;
-
 import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
 
 import java.util.regex.Matcher;
@@ -15,11 +12,10 @@ 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_0_6_4 = new Version("0.6.4", 0, 6, 4);
     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;
 
     private String originalVersion = "?";
     private int major = 0;
@@ -64,7 +60,7 @@ public class Version implements Comparable<Version> {
     public static Version of(String versionString) {
         int major = 0, minor = 0, micro = 0;
         if (versionString != null) {
-            String[] split = versionString.split("\\.");
+            final String[] split = versionString.split("\\.");
             if (split.length > 0) {
                 major = extractNumber(split[0]);
                 if (split.length > 1) {
@@ -87,18 +83,12 @@ public class Version implements Comparable<Version> {
     }
 
     @NonNull
-    public static Version minimumSupported(@NonNull Context context) {
-        if (VERSION_MINIMUM_SUPPORTED == null) {
-            final int minimumServerAppMajor = context.getResources().getInteger(R.integer.minimum_server_app_major);
-            final int minimumServerAppMinor = context.getResources().getInteger(R.integer.minimum_server_app_minor);
-            final int minimumServerAppPatch = context.getResources().getInteger(R.integer.minimum_server_app_patch);
-            VERSION_MINIMUM_SUPPORTED = new Version(minimumServerAppMajor + "." + minimumServerAppMinor + "." + minimumServerAppPatch, minimumServerAppMajor, minimumServerAppMinor, minimumServerAppPatch);
-        }
-        return VERSION_MINIMUM_SUPPORTED;
+    public static Version minimumSupported() {
+        return VERSION_0_6_4;
     }
 
-    public boolean isSupported(@NonNull Context context) {
-        return isGreaterOrEqualTo(Version.minimumSupported(context));
+    public boolean isSupported() {
+        return isGreaterOrEqualTo(minimumSupported());
     }
 
     /**
@@ -167,9 +157,7 @@ public class Version implements Comparable<Version> {
      * @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);
+        return isGreaterOrEqualTo(VERSION_1_3_0);
     }
 
     /**
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/EWidgetType.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/EWidgetType.java
new file mode 100644
index 000000000..6121c7515
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/EWidgetType.java
@@ -0,0 +1,45 @@
+package it.niedermann.nextcloud.deck.model.widget.filter;
+
+import it.niedermann.nextcloud.deck.ui.widget.filter.FilterWidget;
+import it.niedermann.nextcloud.deck.ui.widget.stack.StackWidget;
+import it.niedermann.nextcloud.deck.ui.widget.upcoming.UpcomingWidget;
+
+public enum EWidgetType {
+    FILTER_WIDGET(1, FilterWidget.class),
+    UPCOMING_WIDGET(2, UpcomingWidget.class),
+    STACK_WIDGET(3, StackWidget.class);
+
+    private final int id;
+    private final Class<?> widgetClass;
+
+    EWidgetType(int id, Class<?> widgetClass) {
+        this.id = id;
+        this.widgetClass = widgetClass;
+    }
+
+    public static EWidgetType findById(int id) {
+        for (EWidgetType s : EWidgetType.values()) {
+            if (s.getId() == id) {
+                return s;
+            }
+        }
+        throw new IllegalArgumentException("unknown " + EWidgetType.class.getSimpleName() + " key: " + id);
+    }
+
+    public static EWidgetType findByClass(Class<?> clazz) {
+        for (EWidgetType s : EWidgetType.values()) {
+            if (s.getWidgetClass() == clazz) {
+                return s;
+            }
+        }
+        throw new IllegalArgumentException("unknown EWidgetType class");
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public Class<?> getWidgetClass() {
+        return widgetClass;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidget.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidget.java
new file mode 100644
index 000000000..d6e7d4b08
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidget.java
@@ -0,0 +1,142 @@
+package it.niedermann.nextcloud.deck.model.widget.filter;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.room.Entity;
+import androidx.room.Ignore;
+import androidx.room.PrimaryKey;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.enums.EDueType;
+
+@Entity()
+public class FilterWidget {
+
+    @PrimaryKey()
+    private int id;
+
+    @Nullable
+    private String title;
+
+    @Nullable
+    private EDueType dueType;
+
+    @NonNull
+    private EWidgetType widgetType = EWidgetType.FILTER_WIDGET;
+
+    @Ignore
+    @NonNull
+    private final List<FilterWidgetAccount> accounts = new ArrayList<>();
+
+    @Ignore
+    @NonNull
+    private final List<FilterWidgetSort> sorts = new ArrayList<>();
+
+    @NonNull
+    public List<FilterWidgetAccount> getAccounts() {
+        return accounts;
+    }
+
+    public FilterWidget() {
+        // Default constructor
+    }
+
+    @Ignore
+    public FilterWidget(int appWidgetId, @NonNull EWidgetType widgetType) {
+        setId(appWidgetId);
+        setWidgetType(widgetType);
+    }
+
+    public void setAccounts(@NonNull List<FilterWidgetAccount> accounts) {
+        this.accounts.clear();
+        this.accounts.addAll(accounts);
+    }
+
+    public Integer getId() {
+        return id;
+    }
+
+    @NonNull
+    public List<FilterWidgetSort> getSorts() {
+        return sorts;
+    }
+
+    @Ignore
+    public void setSorts(@NonNull FilterWidgetSort sorts) {
+        this.sorts.clear();
+        this.sorts.add(sorts);
+    }
+
+    public void setSorts(@NonNull List<FilterWidgetSort> sorts) {
+        this.sorts.clear();
+        this.sorts.addAll(sorts);
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    @Nullable
+    public EDueType getDueType() {
+        return dueType;
+    }
+
+    public void setDueType(@Nullable EDueType dueType) {
+        this.dueType = dueType;
+    }
+
+    @NonNull
+    public EWidgetType getWidgetType() {
+        return widgetType;
+    }
+
+    public void setWidgetType(@NonNull EWidgetType widgetType) {
+        this.widgetType = widgetType;
+    }
+
+    @Nullable
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(@Nullable String title) {
+        this.title = title;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        FilterWidget that = (FilterWidget) o;
+
+        if (id != that.id) return false;
+        if (title != null ? !title.equals(that.title) : that.title != null) return false;
+        if (dueType != that.dueType) return false;
+        if (widgetType != that.widgetType) return false;
+        if (!accounts.equals(that.accounts)) return false;
+        return sorts.equals(that.sorts);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id;
+        result = 31 * result + (title != null ? title.hashCode() : 0);
+        result = 31 * result + (dueType != null ? dueType.hashCode() : 0);
+        result = 31 * result + widgetType.hashCode();
+        result = 31 * result + accounts.hashCode();
+        result = 31 * result + sorts.hashCode();
+        return result;
+    }
+
+    public enum EChangedEntityType {
+        ACCOUNT,
+        BOARD,
+        STACK,
+        LABEL,
+        USER,
+        PROJECT,
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetAccount.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetAccount.java
new file mode 100644
index 000000000..caf4e5dd1
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetAccount.java
@@ -0,0 +1,161 @@
+package it.niedermann.nextcloud.deck.model.widget.filter;
+
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Ignore;
+import androidx.room.Index;
+import androidx.room.PrimaryKey;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.Account;
+
+@Entity(
+        indices = {
+                @Index(value = "filterWidgetId", name = "index_FilterWidgetAccount_filterWidgetId"),
+                @Index(value = "accountId", name = "idx_FilterWidgetAccount_accountId"),
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = Account.class,
+                        parentColumns = "id",
+                        childColumns = "accountId", onDelete = ForeignKey.CASCADE
+                ),
+                @ForeignKey(
+                        entity = FilterWidget.class,
+                        parentColumns = "id",
+                        childColumns = "filterWidgetId", onDelete = ForeignKey.CASCADE
+                ),
+        }
+)
+public class FilterWidgetAccount {
+
+    @PrimaryKey(autoGenerate = true)
+    private Long id;
+    private Long filterWidgetId;
+    private Long accountId;
+    private boolean includeNoUser = true;
+    private boolean includeNoProject = true;
+
+    @Ignore
+    private List<FilterWidgetBoard> boards = new ArrayList<>();
+
+    @Ignore
+    private List<FilterWidgetUser> users = new ArrayList<>();
+
+    @Ignore
+    private List<FilterWidgetProject> projects = new ArrayList<>();
+
+    public FilterWidgetAccount() {
+        // Default constructor
+    }
+
+    @Ignore
+    public FilterWidgetAccount(Long accountId, boolean includeNoUser) {
+        this.setAccountId(accountId);
+        this.setIncludeNoUser(includeNoUser);
+    }
+
+    public void setBoards(List<FilterWidgetBoard> boards) {
+        this.boards = boards;
+    }
+
+    public List<FilterWidgetBoard> getBoards() {
+        return boards;
+    }
+
+    public List<FilterWidgetUser> getUsers() {
+        return users;
+    }
+
+    public void setUsers(List<FilterWidgetUser> users) {
+        this.users = users;
+    }
+
+    @Ignore
+    public void setUsers(FilterWidgetUser user) {
+        this.users = Collections.singletonList(user);
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getFilterWidgetId() {
+        return filterWidgetId;
+    }
+
+    public void setFilterWidgetId(Long filterWidgetId) {
+        this.filterWidgetId = filterWidgetId;
+    }
+
+    public Long getAccountId() {
+        return accountId;
+    }
+
+    public void setAccountId(Long accountId) {
+        this.accountId = accountId;
+    }
+
+    public boolean isIncludeNoUser() {
+        return includeNoUser;
+    }
+
+    public void setIncludeNoUser(boolean includeNoUser) {
+        this.includeNoUser = includeNoUser;
+    }
+
+    public boolean isIncludeNoProject() {
+        return includeNoProject;
+    }
+
+    public void setIncludeNoProject(boolean includeNoProject) {
+        this.includeNoProject = includeNoProject;
+    }
+
+    public List<FilterWidgetProject> getProjects() {
+        return projects;
+    }
+
+    public void setProjects(List<FilterWidgetProject> projects) {
+        this.projects = projects;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        FilterWidgetAccount that = (FilterWidgetAccount) o;
+
+        if (includeNoUser != that.includeNoUser) return false;
+        if (includeNoProject != that.includeNoProject) return false;
+        if (id != null ? !id.equals(that.id) : that.id != null) return false;
+        if (filterWidgetId != null ? !filterWidgetId.equals(that.filterWidgetId) : that.filterWidgetId != null)
+            return false;
+        if (accountId != null ? !accountId.equals(that.accountId) : that.accountId != null)
+            return false;
+        if (boards != null ? !boards.equals(that.boards) : that.boards != null) return false;
+        if (users != null ? !users.equals(that.users) : that.users != null) return false;
+        return projects != null ? projects.equals(that.projects) : that.projects == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id != null ? id.hashCode() : 0;
+        result = 31 * result + (filterWidgetId != null ? filterWidgetId.hashCode() : 0);
+        result = 31 * result + (accountId != null ? accountId.hashCode() : 0);
+        result = 31 * result + (includeNoUser ? 1 : 0);
+        result = 31 * result + (includeNoProject ? 1 : 0);
+        result = 31 * result + (boards != null ? boards.hashCode() : 0);
+        result = 31 * result + (users != null ? users.hashCode() : 0);
+        result = 31 * result + (projects != null ? projects.hashCode() : 0);
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetBoard.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetBoard.java
new file mode 100644
index 000000000..b1697f9b7
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetBoard.java
@@ -0,0 +1,130 @@
+package it.niedermann.nextcloud.deck.model.widget.filter;
+
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Ignore;
+import androidx.room.Index;
+import androidx.room.PrimaryKey;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.Board;
+
+@Entity(
+        indices = {
+                @Index(value = "filterAccountId", name = "idx_FilterWidgetBoard_filterAccountId"),
+                @Index(value = "boardId", name = "idx_FilterWidgetBoard_boardId")
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = Board.class,
+                        parentColumns = "localId",
+                        childColumns = "boardId", onDelete = ForeignKey.CASCADE
+                ),
+                @ForeignKey(
+                        entity = FilterWidgetAccount.class,
+                        parentColumns = "id",
+                        childColumns = "filterAccountId", onDelete = ForeignKey.CASCADE
+                )
+        }
+)
+public class FilterWidgetBoard {
+
+    @PrimaryKey(autoGenerate = true)
+    private Long id;
+    private Long filterAccountId;
+    private Long boardId;
+    private boolean includeNoLabel = true;
+
+    public FilterWidgetBoard() {
+        // Default constructor
+    }
+
+    @Ignore
+    public FilterWidgetBoard(Long boardId, List<FilterWidgetStack> stacks) {
+        this.boardId = boardId;
+        this.stacks = stacks;
+    }
+
+    @Ignore
+    private List<FilterWidgetStack> stacks = new ArrayList<>();
+
+    @Ignore
+    private List<FilterWidgetLabel> labels = new ArrayList<>();
+
+    public List<FilterWidgetLabel> getLabels() {
+        return labels;
+    }
+
+    public void setLabels(List<FilterWidgetLabel> labels) {
+        this.labels = labels;
+    }
+
+    public List<FilterWidgetStack> getStacks() {
+        return stacks;
+    }
+
+    public void setStacks(List<FilterWidgetStack> stacks) {
+        this.stacks = stacks;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getFilterAccountId() {
+        return filterAccountId;
+    }
+
+    public void setFilterAccountId(Long filterAccountId) {
+        this.filterAccountId = filterAccountId;
+    }
+
+    public Long getBoardId() {
+        return boardId;
+    }
+
+    public void setBoardId(Long boardId) {
+        this.boardId = boardId;
+    }
+
+    public boolean isIncludeNoLabel() {
+        return includeNoLabel;
+    }
+
+    public void setIncludeNoLabel(boolean includeNoLabel) {
+        this.includeNoLabel = includeNoLabel;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        FilterWidgetBoard that = (FilterWidgetBoard) o;
+
+        if (includeNoLabel != that.includeNoLabel) return false;
+        if (id != null ? !id.equals(that.id) : that.id != null) return false;
+        if (filterAccountId != null ? !filterAccountId.equals(that.filterAccountId) : that.filterAccountId != null)
+            return false;
+        if (boardId != null ? !boardId.equals(that.boardId) : that.boardId != null) return false;
+        if (stacks != null ? !stacks.equals(that.stacks) : that.stacks != null) return false;
+        return labels != null ? labels.equals(that.labels) : that.labels == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id != null ? id.hashCode() : 0;
+        result = 31 * result + (filterAccountId != null ? filterAccountId.hashCode() : 0);
+        result = 31 * result + (boardId != null ? boardId.hashCode() : 0);
+        result = 31 * result + (includeNoLabel ? 1 : 0);
+        result = 31 * result + (stacks != null ? stacks.hashCode() : 0);
+        result = 31 * result + (labels != null ? labels.hashCode() : 0);
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetLabel.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetLabel.java
new file mode 100644
index 000000000..0df280c98
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetLabel.java
@@ -0,0 +1,79 @@
+package it.niedermann.nextcloud.deck.model.widget.filter;
+
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Index;
+import androidx.room.PrimaryKey;
+
+import it.niedermann.nextcloud.deck.model.Label;
+
+@Entity(
+        indices = {
+                @Index(value = "filterBoardId", name = "idx_FilterWidgetLabel_filterBoardId"),
+                @Index(value = "labelId", name = "idx_FilterWidgetLabel_labelId")
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = Label.class,
+                        parentColumns = "localId",
+                        childColumns = "labelId", onDelete = ForeignKey.CASCADE
+                ),
+                @ForeignKey(
+                        entity = FilterWidgetBoard.class,
+                        parentColumns = "id",
+                        childColumns = "filterBoardId", onDelete = ForeignKey.CASCADE
+                )
+        }
+)
+public class FilterWidgetLabel {
+
+    @PrimaryKey(autoGenerate = true)
+    private Long id;
+    private Long filterBoardId;
+    private Long labelId;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getFilterBoardId() {
+        return filterBoardId;
+    }
+
+    public void setFilterBoardId(Long filterBoardId) {
+        this.filterBoardId = filterBoardId;
+    }
+
+    public Long getLabelId() {
+        return labelId;
+    }
+
+    public void setLabelId(Long labelId) {
+        this.labelId = labelId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        FilterWidgetLabel that = (FilterWidgetLabel) o;
+
+        if (id != null ? !id.equals(that.id) : that.id != null) return false;
+        if (filterBoardId != null ? !filterBoardId.equals(that.filterBoardId) : that.filterBoardId != null)
+            return false;
+        return labelId != null ? labelId.equals(that.labelId) : that.labelId == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id != null ? id.hashCode() : 0;
+        result = 31 * result + (filterBoardId != null ? filterBoardId.hashCode() : 0);
+        result = 31 * result + (labelId != null ? labelId.hashCode() : 0);
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetProject.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetProject.java
new file mode 100644
index 000000000..7ed3f956c
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetProject.java
@@ -0,0 +1,89 @@
+package it.niedermann.nextcloud.deck.model.widget.filter;
+
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Ignore;
+import androidx.room.Index;
+import androidx.room.PrimaryKey;
+
+import it.niedermann.nextcloud.deck.model.ocs.projects.OcsProject;
+
+@Entity(
+        indices = {
+                @Index(value = "filterAccountId", name = "idx_FilterWidgetProject_filterAccountId"),
+                @Index(value = "projectId", name = "idx_FilterWidgetProject_projectId")
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = OcsProject.class,
+                        parentColumns = "localId",
+                        childColumns = "projectId", onDelete = ForeignKey.CASCADE
+                ),
+                @ForeignKey(
+                        entity = FilterWidgetAccount.class,
+                        parentColumns = "id",
+                        childColumns = "filterAccountId", onDelete = ForeignKey.CASCADE
+                )
+        }
+)
+public class FilterWidgetProject {
+
+    @PrimaryKey(autoGenerate = true)
+    private Long id;
+    private Long filterAccountId;
+    private Long projectId;
+
+    public FilterWidgetProject() {
+        // Default constructor
+    }
+
+    @Ignore
+    public FilterWidgetProject(Long projectId) {
+        this.projectId = projectId;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getFilterAccountId() {
+        return filterAccountId;
+    }
+
+    public void setFilterAccountId(Long filterAccountId) {
+        this.filterAccountId = filterAccountId;
+    }
+
+    public Long getProjectId() {
+        return projectId;
+    }
+
+    public void setProjectId(Long projectId) {
+        this.projectId = projectId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        FilterWidgetProject that = (FilterWidgetProject) o;
+
+        if (id != null ? !id.equals(that.id) : that.id != null) return false;
+        if (filterAccountId != null ? !filterAccountId.equals(that.filterAccountId) : that.filterAccountId != null)
+            return false;
+        return projectId != null ? projectId.equals(that.projectId) : that.projectId == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id != null ? id.hashCode() : 0;
+        result = 31 * result + (filterAccountId != null ? filterAccountId.hashCode() : 0);
+        result = 31 * result + (projectId != null ? projectId.hashCode() : 0);
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetSort.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetSort.java
new file mode 100644
index 000000000..ae6516c94
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetSort.java
@@ -0,0 +1,126 @@
+package it.niedermann.nextcloud.deck.model.widget.filter;
+
+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 it.niedermann.nextcloud.deck.model.enums.ESortCriteria;
+
+@Entity(
+        indices = {
+                @Index(value = "filterWidgetId", name = "idx_FilterWidgetSort_filterWidgetId"),
+                @Index(value = {"filterWidgetId", "criteria"}, name = "unique_idx_FilterWidgetSort_filterWidgetId_criteria"),
+                @Index(value = {"filterWidgetId", "ruleOrder"}, name = "unique_idx_FilterWidgetSort_filterWidgetId_ruleOrder"),
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = FilterWidget.class,
+                        parentColumns = "id",
+                        childColumns = "filterWidgetId", onDelete = ForeignKey.CASCADE
+                )
+        }
+)
+public class FilterWidgetSort {
+
+    @PrimaryKey(autoGenerate = true)
+    private Long id;
+    private Long filterWidgetId;
+    private boolean direction = true;
+    @NonNull
+    private ESortCriteria criteria;
+    private int ruleOrder;
+
+    public FilterWidgetSort() {
+        // Default constructor
+    }
+
+    @Ignore
+    public FilterWidgetSort(ESortCriteria criteria, boolean ascending) {
+        setCriteria(criteria);
+        setDirection(ascending);
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getFilterWidgetId() {
+        return filterWidgetId;
+    }
+
+    public void setFilterWidgetId(Long filterWidgetId) {
+        this.filterWidgetId = filterWidgetId;
+    }
+
+    public boolean isDirectionAscending() {
+        return direction;
+    }
+
+    public boolean isDirectionDescending() {
+        return !direction;
+    }
+
+    public void setDirectionAscending() {
+        direction = true;
+    }
+
+    public void setDirectionDescending() {
+        direction = false;
+    }
+
+    public ESortCriteria getCriteria() {
+        return criteria;
+    }
+
+    public void setCriteria(ESortCriteria criteria) {
+        this.criteria = criteria;
+    }
+
+    public int getRuleOrder() {
+        return ruleOrder;
+    }
+
+    public void setRuleOrder(int ruleOrder) {
+        this.ruleOrder = ruleOrder;
+    }
+
+    public boolean isDirection() {
+        return direction;
+    }
+
+    public void setDirection(boolean direction) {
+        this.direction = direction;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof FilterWidgetSort)) return false;
+
+        FilterWidgetSort that = (FilterWidgetSort) o;
+
+        if (direction != that.direction) return false;
+        if (ruleOrder != that.ruleOrder) return false;
+        if (id != null ? !id.equals(that.id) : that.id != null) return false;
+        if (filterWidgetId != null ? !filterWidgetId.equals(that.filterWidgetId) : that.filterWidgetId != null)
+            return false;
+        return criteria == that.criteria;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id != null ? id.hashCode() : 0;
+        result = 31 * result + (filterWidgetId != null ? filterWidgetId.hashCode() : 0);
+        result = 31 * result + (direction ? 1 : 0);
+        result = 31 * result + (criteria != null ? criteria.hashCode() : 0);
+        result = 31 * result + ruleOrder;
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetStack.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetStack.java
new file mode 100644
index 000000000..2da1c0b79
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetStack.java
@@ -0,0 +1,89 @@
+package it.niedermann.nextcloud.deck.model.widget.filter;
+
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Ignore;
+import androidx.room.Index;
+import androidx.room.PrimaryKey;
+
+import it.niedermann.nextcloud.deck.model.Stack;
+
+@Entity(
+        indices = {
+                @Index(value = "filterBoardId", name = "idx_FilterWidgetStack_filterBoardId"),
+                @Index(value = "stackId", name = "idx_FilterWidgetStack_stackId")
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = Stack.class,
+                        parentColumns = "localId",
+                        childColumns = "stackId", onDelete = ForeignKey.CASCADE
+                ),
+                @ForeignKey(
+                        entity = FilterWidgetBoard.class,
+                        parentColumns = "id",
+                        childColumns = "filterBoardId", onDelete = ForeignKey.CASCADE
+                )
+        }
+)
+public class FilterWidgetStack {
+
+    @PrimaryKey(autoGenerate = true)
+    private Long id;
+    private Long filterBoardId;
+    private Long stackId;
+
+    public FilterWidgetStack() {
+        // Default constructor
+    }
+
+    @Ignore
+    public FilterWidgetStack(Long stackId) {
+        this.stackId = stackId;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getFilterBoardId() {
+        return filterBoardId;
+    }
+
+    public void setFilterBoardId(Long filterBoardId) {
+        this.filterBoardId = filterBoardId;
+    }
+
+    public Long getStackId() {
+        return stackId;
+    }
+
+    public void setStackId(Long stackId) {
+        this.stackId = stackId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        FilterWidgetStack that = (FilterWidgetStack) o;
+
+        if (id != null ? !id.equals(that.id) : that.id != null) return false;
+        if (filterBoardId != null ? !filterBoardId.equals(that.filterBoardId) : that.filterBoardId != null)
+            return false;
+        return stackId != null ? stackId.equals(that.stackId) : that.stackId == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id != null ? id.hashCode() : 0;
+        result = 31 * result + (filterBoardId != null ? filterBoardId.hashCode() : 0);
+        result = 31 * result + (stackId != null ? stackId.hashCode() : 0);
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetUser.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetUser.java
new file mode 100644
index 000000000..9fd69aa85
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/FilterWidgetUser.java
@@ -0,0 +1,89 @@
+package it.niedermann.nextcloud.deck.model.widget.filter;
+
+import androidx.room.Entity;
+import androidx.room.ForeignKey;
+import androidx.room.Ignore;
+import androidx.room.Index;
+import androidx.room.PrimaryKey;
+
+import it.niedermann.nextcloud.deck.model.User;
+
+@Entity(
+        indices = {
+                @Index(value = "filterAccountId", name = "idx_FilterWidgetUser_filterAccountId"),
+                @Index(value = "userId", name = "idx_FilterWidgetUser_userId")
+        },
+        foreignKeys = {
+                @ForeignKey(
+                        entity = User.class,
+                        parentColumns = "localId",
+                        childColumns = "userId", onDelete = ForeignKey.CASCADE
+                ),
+                @ForeignKey(
+                        entity = FilterWidgetAccount.class,
+                        parentColumns = "id",
+                        childColumns = "filterAccountId", onDelete = ForeignKey.CASCADE
+                )
+        }
+)
+public class FilterWidgetUser {
+
+    @PrimaryKey(autoGenerate = true)
+    private Long id;
+    private Long filterAccountId;
+    private Long userId;
+
+    public FilterWidgetUser() {
+        // Default constructor
+    }
+
+    @Ignore
+    public FilterWidgetUser(Long userId) {
+        this.userId = userId;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getFilterAccountId() {
+        return filterAccountId;
+    }
+
+    public void setFilterAccountId(Long filterAccountId) {
+        this.filterAccountId = filterAccountId;
+    }
+
+    public Long getUserId() {
+        return userId;
+    }
+
+    public void setUserId(Long userId) {
+        this.userId = userId;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        FilterWidgetUser that = (FilterWidgetUser) o;
+
+        if (id != null ? !id.equals(that.id) : that.id != null) return false;
+        if (filterAccountId != null ? !filterAccountId.equals(that.filterAccountId) : that.filterAccountId != null)
+            return false;
+        return userId != null ? userId.equals(that.userId) : that.userId == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = id != null ? id.hashCode() : 0;
+        result = 31 * result + (filterAccountId != null ? filterAccountId.hashCode() : 0);
+        result = 31 * result + (userId != null ? userId.hashCode() : 0);
+        return result;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/dto/FilterWidgetCard.java b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/dto/FilterWidgetCard.java
new file mode 100644
index 000000000..2aaebb129
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/model/widget/filter/dto/FilterWidgetCard.java
@@ -0,0 +1,45 @@
+package it.niedermann.nextcloud.deck.model.widget.filter.dto;
+
+import it.niedermann.nextcloud.deck.model.Board;
+import it.niedermann.nextcloud.deck.model.Stack;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
+
+public class FilterWidgetCard {
+    private FullCard card;
+    private Stack stack;
+    private Board board;
+
+    public FilterWidgetCard() {
+        // Default constructor
+    }
+
+    public FilterWidgetCard(FullCard card, Stack stack, Board board) {
+        this.card = card;
+        this.stack = stack;
+        this.board = board;
+    }
+
+    public FullCard getCard() {
+        return card;
+    }
+
+    public void setCard(FullCard card) {
+        this.card = card;
+    }
+
+    public Stack getStack() {
+        return stack;
+    }
+
+    public void setStack(Stack stack) {
+        this.stack = stack;
+    }
+
+    public Board getBoard() {
+        return board;
+    }
+
+    public void setBoard(Board board) {
+        this.board = board;
+    }
+}
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 d93835423..de0acc53b 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
@@ -37,6 +37,7 @@ 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.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.exceptions.DeckException;
 import it.niedermann.nextcloud.deck.exceptions.OfflineException;
 import it.niedermann.nextcloud.deck.model.AccessControl;
@@ -61,6 +62,8 @@ 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.projects.OcsProjectResource;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidget;
+import it.niedermann.nextcloud.deck.model.widget.filter.dto.FilterWidgetCard;
 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;
@@ -103,10 +106,14 @@ public class SyncManager {
 
     @AnyThread
     public SyncManager(@NonNull Context context, @Nullable String ssoAccountName) {
-        appContext = context.getApplicationContext();
-        LastSyncUtil.init(appContext);
-        this.dataBaseAdapter = new DataBaseAdapter(appContext);
-        this.serverAdapter = new ServerAdapter(appContext, ssoAccountName);
+        this(context, new DataBaseAdapter(context.getApplicationContext()), new ServerAdapter(context.getApplicationContext(), ssoAccountName));
+        LastSyncUtil.init(context.getApplicationContext());
+    }
+
+    private SyncManager(@NonNull Context context, @NonNull DataBaseAdapter databaseAdapter, @NonNull ServerAdapter serverAdapter) {
+        this.appContext = context.getApplicationContext();
+        this.dataBaseAdapter = databaseAdapter;
+        this.serverAdapter = serverAdapter;
     }
 
     @AnyThread
@@ -208,8 +215,13 @@ public class SyncManager {
             refreshCapabilities(new IResponseCallback<Capabilities>(responseCallback.getAccount()) {
                 @Override
                 public void onResponse(Capabilities response) {
+                    if (response != null) {
+                        // When importing an account, the create account color can only be applied after the initial capabilities refresh
+                        callbackAccount.setColor(response.getColor());
+                    }
+
                     if (response != null && !response.isMaintenanceEnabled()) {
-                        if (response.getDeckVersion().isSupported(appContext)) {
+                        if (response.getDeckVersion().isSupported()) {
                             long accountId = callbackAccountId;
                             Instant lastSyncDate = LastSyncUtil.getLastSyncDate(callbackAccountId);
 
@@ -260,12 +272,12 @@ public class SyncManager {
                             }
                         } else {
                             respondCallbacksAfterSync(callbacksQueueForSync, Boolean.FALSE, null);
-                            DeckLog.warn("No sync. Server version not supported: " + response.getDeckVersion().getOriginalVersion());
+                            DeckLog.warn("No sync. Server version not supported:", response.getDeckVersion().getOriginalVersion());
                         }
                     } else {
                         respondCallbacksAfterSync(callbacksQueueForSync, Boolean.FALSE, null);
                         if (response != null) {
-                            DeckLog.warn("No sync. Status maintenance mode: " + response.isMaintenanceEnabled());
+                            DeckLog.warn("No sync. Status maintenance mode:", response.isMaintenanceEnabled());
                         }
                     }
                 }
@@ -369,6 +381,11 @@ public class SyncManager {
         return dataBaseAdapter.readAccount(id);
     }
 
+    @WorkerThread
+    public Account readAccountDirectly(long id) {
+        return dataBaseAdapter.readAccountDirectly(id);
+    }
+
     @AnyThread
     public LiveData<Account> readAccount(@Nullable String name) {
         return dataBaseAdapter.readAccount(name);
@@ -379,6 +396,11 @@ public class SyncManager {
         return dataBaseAdapter.readAccounts();
     }
 
+    @WorkerThread
+    public List<Account> readAccountsDirectly() {
+        return dataBaseAdapter.getAllAccountsDirectly();
+    }
+
     /**
      * <p>
      * Since the return value is a {@link LiveData}, it should immediately return the available values from the database
@@ -423,6 +445,7 @@ public class SyncManager {
                         Account acc = dataBaseAdapter.getAccountByIdDirectly(account.getId());
                         acc.applyCapabilities(response.getResponse(), response.getHeaders().get("ETag"));
                         dataBaseAdapter.updateAccount(acc);
+                        callback.getAccount().setServerDeckVersion(acc.getServerDeckVersion());
                         callback.onResponse(response.getResponse());
                     }
 
@@ -434,14 +457,14 @@ 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.");
+                                DeckLog.verbose("HTTP Status", HTTP_UNAVAILABLE + ": This server seems to be in maintenance mode.");
                                 if (capabilities.isMaintenanceEnabled()) {
                                     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.");
+                                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());
@@ -524,14 +547,12 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<FullBoard> createBoard(long accountId, @NonNull Board board) {
-        WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
+    public void createBoard(long accountId, @NonNull Board board, @NonNull ResponseCallback<FullBoard> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             User owner = dataBaseAdapter.getUserByUidDirectly(accountId, account.getUserName());
             if (owner == null) {
-                DeckLog.log("owner is null - this can be the case if the Deck app has never before been opened in the webinterface");
-                liveData.postValue(null);
+                callback.onError(new Exception("Owner is null. This can be the case if the Deck app has never before been opened in the webinterface"));
             } else {
                 FullBoard fullBoard = new FullBoard();
                 board.setOwnerId(owner.getLocalId());
@@ -539,21 +560,9 @@ public class SyncManager {
                 fullBoard.setBoard(board);
                 board.setAccountId(accountId);
                 fullBoard.setAccountId(accountId);
-                new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new BoardDataProvider(), fullBoard, new IResponseCallback<FullBoard>(account) {
-                    @Override
-                    public void onResponse(FullBoard response) {
-                        liveData.postValue(response);
-                    }
-
-                    @SuppressLint("MissingSuperCall")
-                    @Override
-                    public void onError(Throwable throwable, FullBoard entity) {
-                        liveData.postError(throwable, entity);
-                    }
-                });
+                new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new BoardDataProvider(), fullBoard, IResponseCallback.from(account, callback));
             }
         });
-        return liveData;
     }
 
     /**
@@ -562,18 +571,14 @@ public class SyncManager {
      *
      * @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, @ColorInt int targetBoardColor, boolean cloneCards) {
-        final WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
-
+    public void cloneBoard(long originAccountId, long originBoardLocalId, long targetAccountId, @ColorInt int targetBoardColor, boolean cloneCards, @NonNull ResponseCallback<FullBoard> callback) {
         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."));
+                callback.onError(new DeckException(DeckException.Hint.UNKNOWN_ACCOUNT_USER_ID, "User with Account-UID \"" + originAccount.getUserName() + "\" not found."));
                 return;
             }
             FullBoard originalBoard = dataBaseAdapter.getFullBoardByLocalIdDirectly(originAccountId, originBoardLocalId);
@@ -663,7 +668,7 @@ public class SyncManager {
                                 if (newLabelId != null) {
                                     dataBaseAdapter.createJoinCardWithLabel(newLabelId, createdCardId, DBStatus.LOCAL_EDITED);
                                 } else
-                                    DeckLog.error("ID of created Label is null! Skipping assignment of \"" + oldLabel.getTitle() + "\"...");
+                                    DeckLog.error("ID of created Label is null! Skipping assignment of ", oldLabel.getTitle(), "…");
                             }
                         }
                         if (isSameAccount && oldCard.getAssignedUsers() != null) {
@@ -686,20 +691,19 @@ public class SyncManager {
                         .setResponseCallback(new IResponseCallback<Boolean>(targetAccount) {
                             @Override
                             public void onResponse(Boolean response) {
-                                liveData.postValue(dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, newBoardId));
+                                callback.onResponse(dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, newBoardId));
                             }
 
+                            @SuppressLint("MissingSuperCall")
                             @Override
                             public void onError(Throwable throwable) {
-                                super.onError(throwable);
-                                liveData.postError(throwable);
+                                callback.onError(throwable);
                             }
                         }).doUpSyncFor(new BoardWithStacksAndLabelsUpSyncDataProvider(dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, newBoardId)));
             } else {
-                liveData.postValue(dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, newBoardId));
+                callback.onResponse(dataBaseAdapter.getFullBoardByLocalIdDirectly(targetAccountId, newBoardId));
             }
         });
-        return liveData;
     }
 
     @AnyThread
@@ -715,7 +719,7 @@ public class SyncManager {
                                 }
                             }).doSyncFor(new ActivityDataProvider(null, card));
                 } else {
-                    DeckLog.log("Can not fetch activities for card \"" + card.getTitle() + "\" because this card does not have a remote id yet.");
+                    DeckLog.log("Can not fetch activities for card ", card.getTitle(), "because this card does not have a remote id yet.");
                 }
             }
         });
@@ -755,17 +759,15 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<Void> deleteComment(long accountId, long localCardId, long localCommentId) {
-        WrappedLiveData<Void> liveData = new WrappedLiveData<>();
+    public void deleteComment(long accountId, long localCardId, long localCommentId, @NonNull ResponseCallback<Void> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             Card card = dataBaseAdapter.getCardByLocalIdDirectly(accountId, localCardId);
             DeckComment entity = dataBaseAdapter.getCommentByLocalIdDirectly(accountId, localCommentId);
             OcsComment commentEntity = OcsComment.of(entity);
             new DataPropagationHelper(serverAdapter, dataBaseAdapter).deleteEntity(new DeckCommentsDataProvider(null, card),
-                    commentEntity, getCallbackToLiveDataConverter(account, liveData));
+                    commentEntity, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     public LiveData<List<FullDeckComment>> getFullCommentsForLocalCardId(long localCardId) {
@@ -773,37 +775,22 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<Void> deleteBoard(@NonNull Board board) {
-        WrappedLiveData<Void> liveData = new WrappedLiveData<>();
+    public void deleteBoard(@NonNull Board board, @NonNull ResponseCallback<Void> callback) {
         doAsync(() -> {
             long accountId = board.getAccountId();
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             FullBoard fullBoard = dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, board.getLocalId());
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).deleteEntity(new BoardDataProvider(), fullBoard, getCallbackToLiveDataConverter(account, liveData));
+            new DataPropagationHelper(serverAdapter, dataBaseAdapter).deleteEntity(new BoardDataProvider(), fullBoard, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     @AnyThread
-    public WrappedLiveData<FullBoard> updateBoard(@NonNull FullBoard board) {
-        WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
-        long accountId = board.getAccountId();
+    public void updateBoard(@NonNull FullBoard board, @NonNull ResponseCallback<FullBoard> callback) {
         doAsync(() -> {
+            long accountId = board.getAccountId();
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).updateEntity(new BoardDataProvider(), board, new IResponseCallback<FullBoard>(account) {
-                @Override
-                public void onResponse(FullBoard response) {
-                    liveData.postValue(response);
-                }
-
-                @SuppressLint("MissingSuperCall")
-                @Override
-                public void onError(Throwable throwable) {
-                    liveData.postError(throwable);
-                }
-            });
+            new DataPropagationHelper(serverAdapter, dataBaseAdapter).updateEntity(new BoardDataProvider(), board, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     public LiveData<List<Stack>> getStacksForBoard(long accountId, long localBoardId) {
@@ -814,20 +801,23 @@ public class SyncManager {
         return dataBaseAdapter.getStack(accountId, localStackId);
     }
 
+    @WorkerThread
+    public Long getBoardLocalIdByLocalCardIdDirectly(long localCardId) {
+        return dataBaseAdapter.getBoardLocalIdByLocalCardIdDirectly(localCardId);
+    }
+
     @AnyThread
-    public WrappedLiveData<AccessControl> createAccessControl(long accountId, AccessControl entity) {
-        WrappedLiveData<AccessControl> liveData = new WrappedLiveData<>();
+    public void createAccessControl(long accountId, @NonNull AccessControl entity, @NonNull ResponseCallback<AccessControl> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             FullBoard board = dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, entity.getBoardId());
             new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(
-                    new AccessControlDataProvider(null, board, Collections.singletonList(entity)), entity, getCallbackToLiveDataConverter(account, liveData), ((entity1, response) -> {
+                    new AccessControlDataProvider(null, board, Collections.singletonList(entity)), entity, IResponseCallback.from(account, callback), ((entity1, response) -> {
                         response.setBoardId(entity.getBoardId());
                         response.setUserId(entity.getUser().getLocalId());
                     })
             );
         });
-        return liveData;
     }
 
     @WorkerThread
@@ -840,36 +830,17 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<AccessControl> updateAccessControl(@NonNull AccessControl entity) {
-        WrappedLiveData<AccessControl> liveData = new WrappedLiveData<>();
+    public void updateAccessControl(@NonNull AccessControl entity, @NonNull ResponseCallback<AccessControl> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(entity.getAccountId());
             FullBoard board = dataBaseAdapter.getFullBoardByLocalIdDirectly(entity.getAccountId(), entity.getBoardId());
             new DataPropagationHelper(serverAdapter, dataBaseAdapter).updateEntity(
-                    new AccessControlDataProvider(null, board, Collections.singletonList(entity)), entity, getCallbackToLiveDataConverter(account, liveData));
+                    new AccessControlDataProvider(null, board, Collections.singletonList(entity)), entity, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     @AnyThread
-    private <T> IResponseCallback<T> getCallbackToLiveDataConverter(Account account, @NonNull WrappedLiveData<T> liveData) {
-        return new IResponseCallback<T>(account) {
-            @Override
-            public void onResponse(T response) {
-                liveData.postValue(response);
-            }
-
-            @SuppressLint("MissingSuperCall")
-            @Override
-            public void onError(Throwable throwable) {
-                liveData.postError(throwable);
-            }
-        };
-    }
-
-    @AnyThread
-    public WrappedLiveData<Void> deleteAccessControl(@NonNull AccessControl entity) {
-        WrappedLiveData<Void> liveData = new WrappedLiveData<>();
+    public void deleteAccessControl(@NonNull AccessControl entity, @NonNull ResponseCallback<Void> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(entity.getAccountId());
             FullBoard board = dataBaseAdapter.getFullBoardByLocalIdDirectly(entity.getAccountId(), entity.getBoardId());
@@ -881,17 +852,16 @@ public class SyncManager {
                             if (entity.getAccountId() == entity.getAccountId() && entity.getUser().getUid().equals(account.getUserName())) {
                                 dataBaseAdapter.deleteBoardPhysically(board.getBoard());
                             }
-                            liveData.postValue(response);
+                            callback.onResponse(response);
                         }
 
                         @SuppressLint("MissingSuperCall")
                         @Override
                         public void onError(Throwable throwable) {
-                            liveData.postError(throwable);
+                            callback.onError(throwable);
                         }
                     });
         });
-        return liveData;
     }
 
     public LiveData<FullBoard> getFullBoardById(Long accountId, Long localId) {
@@ -899,8 +869,7 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<FullStack> createStack(long accountId, @NonNull String title, long boardLocalId) {
-        WrappedLiveData<FullStack> liveData = new WrappedLiveData<>();
+    public void createStack(long accountId, @NonNull String title, long boardLocalId, @NonNull ResponseCallback<FullStack> callback) {
         doAsync(() -> {
             Stack stack = new Stack(title, boardLocalId);
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
@@ -911,65 +880,34 @@ public class SyncManager {
             stack.setBoardId(board.getLocalId());
             fullStack.setStack(stack);
             fullStack.setAccountId(accountId);
-            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);
-                }
-            });
+            new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new StackDataProvider(null, board), fullStack, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     @AnyThread
-    public WrappedLiveData<Void> deleteStack(long accountId, long stackLocalId, long boardLocalId) {
-        WrappedLiveData<Void> liveData = new WrappedLiveData<>();
+    public void deleteStack(long accountId, long stackLocalId, long boardLocalId, @NonNull ResponseCallback<Void> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             FullStack fullStack = dataBaseAdapter.getFullStackByLocalIdDirectly(stackLocalId);
             FullBoard board = dataBaseAdapter.getFullBoardByLocalIdDirectly(accountId, boardLocalId);
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).deleteEntity(new StackDataProvider(null, board), fullStack, getCallbackToLiveDataConverter(account, liveData));
+            new DataPropagationHelper(serverAdapter, dataBaseAdapter).deleteEntity(new StackDataProvider(null, board), fullStack, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     @AnyThread
-    public WrappedLiveData<FullStack> updateStackTitle(long localStackId, @NonNull String newTitle) {
-        WrappedLiveData<FullStack> liveData = new WrappedLiveData<>();
+    public void updateStackTitle(long localStackId, @NonNull String newTitle, @NonNull ResponseCallback<FullStack> callback) {
         doAsync(() -> {
             FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(localStackId);
             FullBoard fullBoard = dataBaseAdapter.getFullBoardByLocalIdDirectly(stack.getAccountId(), stack.getStack().getBoardId());
             Account account = dataBaseAdapter.getAccountByIdDirectly(stack.getAccountId());
             stack.getStack().setTitle(newTitle);
-            updateStack(account, fullBoard, stack, liveData);
+            updateStack(account, fullBoard, stack, callback);
         });
-        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);
-                }
-            }
-
-            @SuppressLint("MissingSuperCall")
-            @Override
-            public void onError(Throwable throwable) {
-                if (liveData != null) {
-                    liveData.postError(throwable);
-                }
-            }
-        }));
+    private void updateStack(@NonNull Account account, @NonNull FullBoard board, @NonNull FullStack stack, @NonNull ResponseCallback<FullStack> callback) {
+        doAsync(() -> new DataPropagationHelper(serverAdapter, dataBaseAdapter).updateEntity(new StackDataProvider(null, board), stack, IResponseCallback.from(account, callback)));
     }
 
     /**
@@ -994,8 +932,8 @@ public class SyncManager {
             int orderFirst = stacks.first.getStack().getOrder();
             stacks.first.getStack().setOrder(stacks.second.getStack().getOrder());
             stacks.second.getStack().setOrder(orderFirst);
-            updateStack(account, fullBoard, stacks.first, null);
-            updateStack(account, fullBoard, stacks.second, null);
+            updateStack(account, fullBoard, stacks.first, ResponseCallback.empty());
+            updateStack(account, fullBoard, stacks.second, ResponseCallback.empty());
         });
     }
 
@@ -1087,7 +1025,6 @@ public class SyncManager {
                 }
             }
 
-
             if (serverAdapter.hasInternetConnection()) {
                 new SyncHelper(serverAdapter, dataBaseAdapter, null)
                         .setResponseCallback(new IResponseCallback<Boolean>(account) {
@@ -1099,7 +1036,7 @@ public class SyncManager {
                             @SuppressLint("MissingSuperCall")
                             @Override
                             public void onError(Throwable throwable) {
-                                if (throwable.getClass() == DeckException.class && ((DeckException)throwable).getHint().equals(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET)) {
+                                if (throwable.getClass() == DeckException.class && ((DeckException) throwable).getHint().equals(DeckException.Hint.DEPENDENCY_NOT_SYNCED_YET)) {
                                     liveData.postValue(card);
                                 } else {
                                     liveData.postError(throwable);
@@ -1115,8 +1052,7 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<Void> deleteCard(@NonNull Card card) {
-        WrappedLiveData<Void> liveData = new WrappedLiveData<>();
+    public void deleteCard(@NonNull Card card, @NonNull ResponseCallback<Void> callback) {
         doAsync(() -> {
             FullCard fullCard = dataBaseAdapter.getFullCardByLocalIdDirectly(card.getAccountId(), card.getLocalId());
             if (fullCard == null) {
@@ -1125,22 +1061,19 @@ public class SyncManager {
             Account account = dataBaseAdapter.getAccountByIdDirectly(card.getAccountId());
             FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getStackId());
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).deleteEntity(new CardPropagationDataProvider(null, board, stack), fullCard, getCallbackToLiveDataConverter(account, liveData));
+            new DataPropagationHelper(serverAdapter, dataBaseAdapter).deleteEntity(new CardPropagationDataProvider(null, board, stack), fullCard, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     @AnyThread
-    public WrappedLiveData<FullCard> archiveCard(@NonNull FullCard card) {
-        WrappedLiveData<FullCard> liveData = new WrappedLiveData<>();
+    public void archiveCard(@NonNull FullCard card, @NonNull ResponseCallback<FullCard> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(card.getAccountId());
             FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getCard().getStackId());
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
             card.getCard().setArchived(true);
-            updateCardForArchive(stack, board, card, getCallbackToLiveDataConverter(account, liveData));
+            updateCardForArchive(stack, board, card, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     private void updateCardForArchive(FullStack stack, Board board, FullCard card, @NonNull IResponseCallback<FullCard> callback) {
@@ -1148,91 +1081,81 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<FullCard> dearchiveCard(@NonNull FullCard card) {
-        WrappedLiveData<FullCard> liveData = new WrappedLiveData<>();
+    public void dearchiveCard(@NonNull FullCard card, @NonNull ResponseCallback<FullCard> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(card.getAccountId());
             FullStack stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getCard().getStackId());
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(stack.getStack().getBoardId());
             card.getCard().setArchived(false);
-            updateCardForArchive(stack, board, card, getCallbackToLiveDataConverter(account, liveData));
+            updateCardForArchive(stack, board, card, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     @AnyThread
-    public WrappedLiveData<Void> archiveCardsInStack(long accountId, long stackLocalId, @NonNull FilterInformation filterInformation) {
-        WrappedLiveData<Void> liveData = new WrappedLiveData<>();
+    public void archiveCardsInStack(long accountId, long stackLocalId, @NonNull FilterInformation filterInformation, @NonNull ResponseCallback<Void> callback) {
         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, filterInformation);
-            if (cards.size() > 0) {
-                CountDownLatch latch = new CountDownLatch(cards.size());
-                for (FullCard card : cards) {
-                    if (card.getCard().isArchived()) {
+            if (cards.size() <= 0) {
+                callback.onResponse(null);
+                return;
+            }
+            final CountDownLatch latch = new CountDownLatch(cards.size());
+            for (FullCard card : cards) {
+                if (card.getCard().isArchived()) {
+                    latch.countDown();
+                    continue;
+                }
+                card.getCard().setArchived(true);
+                updateCardForArchive(stack, board, card, new IResponseCallback<FullCard>(account) {
+                    @Override
+                    public void onResponse(FullCard response) {
                         latch.countDown();
-                        continue;
                     }
-                    card.getCard().setArchived(true);
-                    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();
-                            liveData.postError(throwable);
-                        }
-                    });
-                }
-                try {
-                    latch.await();
-                    liveData.postValue(null);
-                } catch (InterruptedException e) {
-                    liveData.postError(e);
-                }
-            } else {
-                liveData.postValue(null);
+                    @SuppressLint("MissingSuperCall")
+                    @Override
+                    public void onError(Throwable throwable) {
+                        latch.countDown();
+                        callback.onError(throwable);
+                    }
+                });
+            }
+            try {
+                latch.await();
+                callback.onResponse(null);
+            } catch (InterruptedException e) {
+                callback.onError(e);
             }
         });
-        return liveData;
     }
 
     @AnyThread
-    public WrappedLiveData<FullBoard> archiveBoard(@NonNull Board board) {
-        WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
+    public void archiveBoard(@NonNull Board board, @NonNull ResponseCallback<FullBoard> callback) {
         doAsync(() -> {
             try {
                 FullBoard b = dataBaseAdapter.getFullBoardByLocalIdDirectly(board.getAccountId(), board.getLocalId());
                 b.getBoard().setArchived(true);
-                updateBoard(b);
-                liveData.postValue(b);
+                updateBoard(b, callback);
             } catch (Throwable e) {
-                liveData.postError(e);
+                callback.onError(e);
             }
         });
-        return liveData;
     }
 
     @AnyThread
-    public WrappedLiveData<FullBoard> dearchiveBoard(@NonNull Board board) {
-        WrappedLiveData<FullBoard> liveData = new WrappedLiveData<>();
+    public void dearchiveBoard(@NonNull Board board, @NonNull ResponseCallback<FullBoard> callback) {
         doAsync(() -> {
             try {
                 FullBoard b = dataBaseAdapter.getFullBoardByLocalIdDirectly(board.getAccountId(), board.getLocalId());
                 b.getBoard().setArchived(false);
-                updateBoard(b);
-                liveData.postValue(b);
+                updateBoard(b, callback);
             } catch (Throwable e) {
-                liveData.postError(e);
+                callback.onError(e);
             }
         });
-        return liveData;
     }
 
     @AnyThread
@@ -1314,7 +1237,6 @@ public class SyncManager {
     @AnyThread
     public WrappedLiveData<Void> moveCard(long originAccountId, long originCardLocalId, long targetAccountId, long targetBoardLocalId, long targetStackLocalId) {
         return LiveDataHelper.wrapInLiveData(() -> {
-
             final FullCard originalCard = dataBaseAdapter.getFullCardByLocalIdDirectly(originAccountId, originCardLocalId);
             int newIndex = dataBaseAdapter.getHighestCardOrderInStack(targetStackLocalId) + 1;
             final FullBoard originalBoard = dataBaseAdapter.getFullBoardByLocalCardIdDirectly(originCardLocalId);
@@ -1325,7 +1247,7 @@ public class SyncManager {
             }
             // ### get rid of original card where it is now.
             final Card originalInnerCard = originalCard.getCard();
-            deleteCard(new Card(originalInnerCard));
+            deleteCard(new Card(originalInnerCard), ResponseCallback.empty());
             // ### clone card itself
             originalInnerCard.setAccountId(targetAccountId);
             originalInnerCard.setId(null);
@@ -1442,31 +1364,18 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<Label> createLabel(long accountId, Label label, long localBoardId) {
-        WrappedLiveData<Label> liveData = new WrappedLiveData<>();
+    public void createLabel(long accountId, Label label, long localBoardId, @NonNull ResponseCallback<Label> callback) {
         doAsync(() -> {
             Label existing = dataBaseAdapter.getLabelByBoardIdAndTitleDirectly(label.getBoardId(), label.getTitle());
             if (existing != null) {
-                liveData.postError(new SQLiteConstraintException("label \"" + label.getTitle() + "\" already exists for this board!"));
+                callback.onError(new SQLiteConstraintException("label \"" + label.getTitle() + "\" already exists for this board!"));
                 return;
             }
             Account account = dataBaseAdapter.getAccountByIdDirectly(accountId);
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(localBoardId);
             label.setAccountId(accountId);
-            new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new LabelDataProvider(null, board, null), label, new IResponseCallback<Label>(account) {
-                @Override
-                public void onResponse(Label response) {
-                    liveData.postValue(response);
-                }
-
-                @SuppressLint("MissingSuperCall")
-                @Override
-                public void onError(Throwable throwable) {
-                    liveData.postError(throwable);
-                }
-            }, (entity, response) -> response.setBoardId(board.getLocalId()));
+            new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(new LabelDataProvider(null, board, null), label, IResponseCallback.from(account, callback), (entity, response) -> response.setBoardId(board.getLocalId()));
         });
-        return liveData;
     }
 
     public MutableLiveData<Label> createAndAssignLabelToCard(long accountId, @NonNull Label label, long localCardId) {
@@ -1500,27 +1409,23 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<Void> deleteLabel(@NonNull Label label) {
-        WrappedLiveData<Void> liveData = new WrappedLiveData<>();
+    public void deleteLabel(@NonNull Label label, @NonNull ResponseCallback<Void> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(label.getAccountId());
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(label.getBoardId());
             new DataPropagationHelper(serverAdapter, dataBaseAdapter)
-                    .deleteEntity(new LabelDataProvider(null, board, Collections.emptyList()), label, getCallbackToLiveDataConverter(account, liveData));
+                    .deleteEntity(new LabelDataProvider(null, board, Collections.emptyList()), label, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     @AnyThread
-    public WrappedLiveData<Label> updateLabel(@NonNull Label label) {
-        WrappedLiveData<Label> liveData = new WrappedLiveData<>();
+    public void updateLabel(@NonNull Label label, @NonNull ResponseCallback<Label> callback) {
         doAsync(() -> {
             Account account = dataBaseAdapter.getAccountByIdDirectly(label.getAccountId());
             Board board = dataBaseAdapter.getBoardByLocalIdDirectly(label.getBoardId());
             new DataPropagationHelper(serverAdapter, dataBaseAdapter)
-                    .updateEntity(new LabelDataProvider(null, board, Collections.emptyList()), label, getCallbackToLiveDataConverter(account, liveData));
+                    .updateEntity(new LabelDataProvider(null, board, Collections.emptyList()), label, IResponseCallback.from(account, callback));
         });
-        return liveData;
     }
 
     @AnyThread
@@ -1850,8 +1755,7 @@ public class SyncManager {
      * Also this leads to the attachment being present in the card forever with a DBStatus.LOCAL_EDITED
      */
     @AnyThread
-    public WrappedLiveData<Attachment> addAttachmentToCard(long accountId, long localCardId, @NonNull String mimeType, @NonNull File file) {
-        WrappedLiveData<Attachment> liveData = new WrappedLiveData<>();
+    public void addAttachmentToCard(long accountId, long localCardId, @NonNull String mimeType, @NonNull File file, @NonNull ResponseCallback<Attachment> callback) {
         doAsync(() -> {
             Attachment attachment = populateAttachmentEntityForFile(new Attachment(), localCardId, mimeType, file);
             final Instant now = Instant.now();
@@ -1863,10 +1767,9 @@ public class SyncManager {
             Account account = dataBaseAdapter.getAccountByIdDirectly(card.getAccountId());
             new DataPropagationHelper(serverAdapter, dataBaseAdapter).createEntity(
                     new AttachmentDataProvider(null, board, stack, card, Collections.singletonList(attachment)),
-                    attachment, getCallbackToLiveDataConverter(account, liveData)
+                    attachment, IResponseCallback.from(account, callback)
             );
         });
-        return liveData;
     }
 
     @AnyThread
@@ -1911,8 +1814,7 @@ public class SyncManager {
     }
 
     @AnyThread
-    public WrappedLiveData<Void> deleteAttachmentOfCard(long accountId, long localCardId, long localAttachmentId) {
-        WrappedLiveData<Void> liveData = new WrappedLiveData<>();
+    public void deleteAttachmentOfCard(long accountId, long localCardId, long localAttachmentId, @NonNull ResponseCallback<Void> callback) {
         doAsync(() -> {
             if (serverAdapter.hasInternetConnection()) {
                 FullCard card = dataBaseAdapter.getFullCardByLocalIdDirectly(accountId, localCardId);
@@ -1922,16 +1824,75 @@ public class SyncManager {
                 Account account = dataBaseAdapter.getAccountByIdDirectly(card.getAccountId());
 
                 new DataPropagationHelper(serverAdapter, dataBaseAdapter)
-                        .deleteEntity(new AttachmentDataProvider(null, board, stack, card, Collections.singletonList(attachment)), attachment, getCallbackToLiveDataConverter(account, liveData));
+                        .deleteEntity(new AttachmentDataProvider(null, board, stack, card, Collections.singletonList(attachment)), attachment, IResponseCallback.from(account, callback));
             }
         });
-        return liveData;
     }
 
     // -------------------
     // Widgets
     // -------------------
 
+    // # filter widget
+
+    @AnyThread
+    public void createFilterWidget(@NonNull FilterWidget filterWidget, @NonNull ResponseCallback<Integer> callback) {
+        doAsync(() -> {
+            try {
+                int filterWidgetId = dataBaseAdapter.createFilterWidgetDirectly(filterWidget);
+                callback.onResponse(filterWidgetId);
+            } catch (Throwable t) {
+                callback.onError(t);
+            }
+        });
+    }
+
+    @AnyThread
+    public void updateFilterWidget(@NonNull FilterWidget filterWidget, @NonNull IResponseCallback<Boolean> callback) {
+        doAsync(() -> {
+            try {
+                dataBaseAdapter.updateFilterWidgetDirectly(filterWidget);
+                callback.onResponse(Boolean.TRUE);
+            } catch (Throwable t) {
+                callback.onError(t);
+            }
+        });
+    }
+
+    @AnyThread
+    public void getFilterWidget(@NonNull Integer filterWidgetId, @NonNull ResponseCallback<FilterWidget> callback) {
+        doAsync(() -> {
+            try {
+                callback.onResponse(dataBaseAdapter.getFilterWidgetByIdDirectly(filterWidgetId));
+            } catch (Throwable t) {
+                callback.onError(t);
+            }
+        });
+    }
+
+    @AnyThread
+    public void deleteFilterWidget(int filterWidgetId, @NonNull ResponseCallback<Boolean> callback) {
+        doAsync(() -> {
+            try {
+                dataBaseAdapter.deleteFilterWidgetDirectly(filterWidgetId);
+                callback.onResponse(Boolean.TRUE);
+            } catch (Throwable t) {
+                callback.onError(t);
+            }
+        });
+    }
+
+    public boolean filterWidgetExists(int id) {
+        return dataBaseAdapter.filterWidgetExists(id);
+    }
+
+    @WorkerThread
+    public List<FilterWidgetCard> getCardsForFilterWidget(@NonNull Integer filterWidgetId) {
+        return dataBaseAdapter.getCardsForFilterWidget(filterWidgetId);
+    }
+
+    // # single card widget
+
     /**
      * Can be called from a configuration screen or a picker.
      * Creates a new entry in the database, if row with given widgetId does not yet exist.
@@ -1942,10 +1903,10 @@ public class SyncManager {
     }
 
     @WorkerThread
-    public FullSingleCardWidgetModel getSingleCardWidgetModelDirectly(int widgetId) throws NoSuchElementException {
-        final FullSingleCardWidgetModel model = dataBaseAdapter.getFullSingleCardWidgetModel(widgetId);
+    public FullSingleCardWidgetModel getSingleCardWidgetModelDirectly(int appWidgetId) throws NoSuchElementException {
+        final FullSingleCardWidgetModel model = dataBaseAdapter.getFullSingleCardWidgetModel(appWidgetId);
         if (model == null) {
-            throw new NoSuchElementException();
+            throw new NoSuchElementException("There is no " + FullSingleCardWidgetModel.class.getSimpleName() + " with the given appWidgetId " + appWidgetId);
         }
         return model;
     }
@@ -1978,4 +1939,15 @@ public class SyncManager {
     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());
     }
+
+    @WorkerThread
+    public Stack getStackDirectly(long stackLocalId) {
+        return dataBaseAdapter.getStackByLocalIdDirectly(stackLocalId);
+    }
+
+    @ColorInt
+    @WorkerThread
+    public Integer getBoardColorDirectly(long accountId, long localBoardId) {
+        return dataBaseAdapter.getBoardColorDirectly(accountId, localBoardId);
+    }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncWorker.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncWorker.java
index f43cbd34f..af6e08826 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncWorker.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/SyncWorker.java
@@ -40,7 +40,7 @@ public class SyncWorker extends Worker {
             sharedPreferencesEditor.putLong(getApplicationContext().getString(R.string.shared_preference_last_background_sync), System.currentTimeMillis());
             sharedPreferencesEditor.apply();
             boolean success = syncManager.synchronizeEverything();
-            DeckLog.info("Finishing background synchronization with result " + success);
+            DeckLog.info("Finishing background synchronization. Success: ", success);
             return success ? Result.failure() : Result.success();
         }
         return Result.success();
@@ -66,17 +66,17 @@ public class SyncWorker extends Worker {
             unit = TimeUnit.HOURS;
         }
         if (unit == null) {
-            DeckLog.info("Do not register a new " + SyncWorker.class.getSimpleName() + " because setting " + preferenceValue + " is not a valid time frame");
+            DeckLog.info("Do not register a new", SyncWorker.class.getSimpleName(), "because setting", preferenceValue, "is not a valid time frame");
         } else {
             final PeriodicWorkRequest work = new PeriodicWorkRequest.Builder(SyncWorker.class, repeatInterval, unit)
                     .setConstraints(constraints).build();
-            DeckLog.info("Registering " + SyncWorker.class.getSimpleName() + " running each " + repeatInterval + " " + unit);
+            DeckLog.info("Registering", SyncWorker.class.getSimpleName(), "running each", repeatInterval, unit);
             WorkManager.getInstance(context.getApplicationContext()).enqueueUniquePeriodicWork(SyncWorker.WORKER_TAG, ExistingPeriodicWorkPolicy.REPLACE, work);
         }
     }
 
     private static void deregister(@NonNull Context context) {
-        DeckLog.info("Deregistering all " + SyncWorker.class.getSimpleName() + " with tag \"" + WORKER_TAG + "\"");
+        DeckLog.info("Deregistering all", SyncWorker.class.getSimpleName(), "with tag", WORKER_TAG);
         WorkManager.getInstance(context.getApplicationContext()).cancelAllWorkByTag(WORKER_TAG);
     }
 }
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 bff8ddfdb..8cadbaec8 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
@@ -24,11 +24,13 @@ import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.api.RequestHelper;
 import it.niedermann.nextcloud.deck.exceptions.OfflineException;
 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.enums.EAttachmentType;
 import it.niedermann.nextcloud.deck.model.full.FullBoard;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
 import it.niedermann.nextcloud.deck.model.full.FullStack;
@@ -51,6 +53,8 @@ import static it.niedermann.nextcloud.deck.util.MimeTypeUtil.TEXT_PLAIN;
 public class ServerAdapter {
 
     private final String prefKeyWifiOnly;
+    private final String prefKeyEtags;
+    final SharedPreferences sharedPreferences;
 
     @NonNull
     private final Context applicationContext;
@@ -63,7 +67,9 @@ public class ServerAdapter {
     public ServerAdapter(@NonNull Context applicationContext, @Nullable String ssoAccountName) {
         this.applicationContext = applicationContext;
         prefKeyWifiOnly = applicationContext.getResources().getString(R.string.pref_key_wifi_only);
+        prefKeyEtags = applicationContext.getResources().getString(R.string.pref_key_etags);
         provider = new ApiProvider(applicationContext, ssoAccountName);
+        sharedPreferences = PreferenceManager.getDefaultSharedPreferences(applicationContext);
     }
 
     public String getServerUrl() {
@@ -88,7 +94,6 @@ public class ServerAdapter {
     public boolean hasInternetConnection() {
         ConnectivityManager cm = (ConnectivityManager) applicationContext.getSystemService(Context.CONNECTIVITY_SERVICE);
         if (cm != null) {
-            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(applicationContext);
             if (sharedPreferences.getBoolean(prefKeyWifiOnly, false)) {
                 if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
                     Network network = cm.getActiveNetwork();
@@ -104,8 +109,6 @@ public class ServerAdapter {
                     }
                     return networkInfo.isConnected();
                 }
-
-
             } else {
                 return cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isConnected();
             }
@@ -126,9 +129,13 @@ public class ServerAdapter {
     }
 
     public void getBoards(IResponseCallback<ParsedResponse<List<FullBoard>>> responseCallback) {
-        RequestHelper.request(provider, () ->
-                        provider.getDeckAPI().getBoards(true, getLastSyncDateFormatted(responseCallback.getAccount().getId()), responseCallback.getAccount().getBoardsEtag()),
-                responseCallback);
+        RequestHelper.request(provider, () -> isEtagsEnabled()
+                ? provider.getDeckAPI().getBoards(true, getLastSyncDateFormatted(responseCallback.getAccount().getId()), responseCallback.getAccount().getBoardsEtag())
+                : provider.getDeckAPI().getBoards(true, getLastSyncDateFormatted(responseCallback.getAccount().getId())), responseCallback);
+    }
+
+    public boolean isEtagsEnabled() {
+        return sharedPreferences.getBoolean(prefKeyEtags, true);
     }
 
     public void getCapabilities(String eTag, IResponseCallback<ParsedResponse<Capabilities>> responseCallback) {
@@ -220,7 +227,13 @@ public class ServerAdapter {
 
     public void getCard(long boardId, long stackId, long cardId, IResponseCallback<FullCard> responseCallback) {
         ensureInternetConnection();
-        RequestHelper.request(provider, () -> provider.getDeckAPI().getCard(boardId, stackId, cardId, getLastSyncDateFormatted(responseCallback.getAccount().getId())), responseCallback);
+        RequestHelper.request(provider, () -> {
+            final Account account = responseCallback.getAccount();
+            if (account != null && account.getServerDeckVersionAsObject().supportsFileAttachments()) {
+                return provider.getDeckAPI().getCard_1_1(boardId, stackId, cardId, getLastSyncDateFormatted(responseCallback.getAccount().getId()));
+            }
+            return provider.getDeckAPI().getCard_1_0(boardId, stackId, cardId, getLastSyncDateFormatted(responseCallback.getAccount().getId()));
+        }, responseCallback);
     }
 
     public void createCard(long boardId, long stackId, Card card, IResponseCallback<FullCard> responseCallback) {
@@ -281,10 +294,14 @@ public class ServerAdapter {
     }
 
     // ## ATTACHMENTS
-    public void uploadAttachment(Long remoteBoardId, long remoteStackId, long remoteCardId, String contentType, File attachment, IResponseCallback<Attachment> responseCallback) {
-        ensureInternetConnection();
-        MultipartBody.Part filePart = MultipartBody.Part.createFormData("file", attachment.getName(), RequestBody.create(MediaType.parse(getMimeType(attachment)), attachment));
-        MultipartBody.Part typePart = MultipartBody.Part.createFormData("type", null, RequestBody.create(MediaType.parse(TEXT_PLAIN), "deck_file"));
+    public void uploadAttachment(Long remoteBoardId, long remoteStackId, long remoteCardId, File attachment, IResponseCallback<Attachment> responseCallback) {
+        ensureInternetConnection();
+        final Account account = responseCallback.getAccount();
+        final String type = (account != null && account.getServerDeckVersionAsObject().supportsFileAttachments())
+                ? EAttachmentType.FILE.getValue()
+                : EAttachmentType.DECK_FILE.getValue();
+        final MultipartBody.Part filePart = MultipartBody.Part.createFormData("file", attachment.getName(), RequestBody.create(MediaType.parse(getMimeType(attachment)), attachment));
+        final MultipartBody.Part typePart = MultipartBody.Part.createFormData("type", null, RequestBody.create(MediaType.parse(TEXT_PLAIN), type));
         RequestHelper.request(provider, () -> provider.getDeckAPI().uploadAttachment(remoteBoardId, remoteStackId, remoteCardId, typePart, filePart), responseCallback);
     }
 
@@ -304,9 +321,13 @@ public class ServerAdapter {
 
     public void updateAttachment(Long remoteBoardId, long remoteStackId, long remoteCardId, long remoteAttachmentId, String contentType, Uri attachmentUri, IResponseCallback<Attachment> responseCallback) {
         ensureInternetConnection();
-        File attachment = new File(attachmentUri.getPath());
-        MultipartBody.Part filePart = MultipartBody.Part.createFormData("file", attachment.getName(), RequestBody.create(MediaType.parse(contentType), attachment));
-        MultipartBody.Part typePart = MultipartBody.Part.createFormData("type", attachment.getName(), RequestBody.create(MediaType.parse(TEXT_PLAIN), "deck_file"));
+        final File attachment = new File(attachmentUri.getPath());
+        final Account account = responseCallback.getAccount();
+        final String type = (account != null && account.getServerDeckVersionAsObject().supportsFileAttachments())
+                ? EAttachmentType.FILE.getValue()
+                : EAttachmentType.DECK_FILE.getValue();
+        final MultipartBody.Part filePart = MultipartBody.Part.createFormData("file", attachment.getName(), RequestBody.create(MediaType.parse(contentType), attachment));
+        final MultipartBody.Part typePart = MultipartBody.Part.createFormData("type", attachment.getName(), RequestBody.create(MediaType.parse(TEXT_PLAIN), type));
         RequestHelper.request(provider, () -> provider.getDeckAPI().updateAttachment(remoteBoardId, remoteStackId, remoteCardId, remoteAttachmentId, typePart, filePart), 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 982844f06..e21d689fe 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
@@ -1,8 +1,11 @@
 package it.niedermann.nextcloud.deck.persistence.sync.adapters.db;
 
+import android.appwidget.AppWidgetManager;
 import android.content.Context;
+import android.content.Intent;
 
 import androidx.annotation.AnyThread;
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.WorkerThread;
@@ -11,7 +14,15 @@ import androidx.sqlite.db.SimpleSQLiteQuery;
 
 import java.time.Instant;
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.model.AccessControl;
@@ -45,23 +56,36 @@ 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.filter.EWidgetType;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidget;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetAccount;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetBoard;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetLabel;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetProject;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetSort;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetStack;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetUser;
+import it.niedermann.nextcloud.deck.model.widget.filter.dto.FilterWidgetCard;
 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;
 
 public class DataBaseAdapter {
 
-    private DeckDatabase db;
+    private final DeckDatabase db;
     @NonNull
-    private Context context;
+    private final Context context;
 
     public DataBaseAdapter(@NonNull Context applicationContext) {
+        this(applicationContext, DeckDatabase.getInstance(applicationContext));
+    }
+
+    private DataBaseAdapter(@NonNull Context applicationContext, @NonNull DeckDatabase db) {
         this.context = applicationContext;
-        this.db = DeckDatabase.getInstance(applicationContext);
+        this.db = db;
     }
 
     @NonNull
@@ -169,7 +193,7 @@ public class DataBaseAdapter {
         }
     }
 
-    private void filterRelationsForCard(@Nullable List<FullCard> card) {
+    private void filterRelationsForCard(@Nullable Collection<FullCard> card) {
         if (card == null) {
             return;
         }
@@ -191,39 +215,51 @@ public class DataBaseAdapter {
 
     }
 
-    private void fillSqlWithListValues(StringBuilder query, List<Object> args, @NonNull List<? extends IRemoteEntity> entities) {
-        for (int i = 0; i < entities.size(); i++) {
+    private void fillSqlWithEntityListValues(StringBuilder query, List<Object> args, @NonNull List<? extends IRemoteEntity> entities) {
+        List<Long> idList = entities.stream().map(IRemoteEntity::getLocalId).collect(Collectors.toList());
+        fillSqlWithListValues(query, args, idList);
+    }
+
+    private void fillSqlWithListValues(StringBuilder query, List<Object> args, @NonNull List<?> values) {
+        for (int i = 0; i < values.size(); i++) {
             if (i > 0) {
                 query.append(", ");
             }
             query.append("?");
-            args.add(entities.get(i).getLocalId());
+            args.add(values.get(i));
         }
     }
 
     @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));
+    public List<FullCard> getFullCardsForStackDirectly(long accountId, long localStackId, @Nullable FilterInformation filter) {
+        return filter == null
+                ? db.getCardDao().getFullCardsForStackDirectly(accountId, localStackId)
+                : db.getCardDao().getFilteredFullCardsForStackDirectly(getQueryForFilter(filter, accountId, localStackId));
     }
 
     @AnyThread
     private SimpleSQLiteQuery getQueryForFilter(FilterInformation filter, long accountId, long localStackId) {
+        return getQueryForFilter(filter, Collections.singletonList(accountId), Collections.singletonList(localStackId));
+    }
+
+    @AnyThread
+    private SimpleSQLiteQuery getQueryForFilter(FilterInformation filter, List<Long> accountIds, List<Long> localStackIds) {
         List<Object> args = new ArrayList<>();
-        args.add(accountId);
-        args.add(localStackId);
-        StringBuilder query = new StringBuilder("SELECT * FROM card c " +
-                "WHERE accountId = ? AND stackId = ? ");
+        StringBuilder query = new StringBuilder("SELECT * FROM card c WHERE 1=1 ");
+        if (accountIds != null && !accountIds.isEmpty()) {
+            query.append("and accountId in (");
+            fillSqlWithListValues(query, args, accountIds);
+            query.append(") ");
+        }
+        if (localStackIds != null && !localStackIds.isEmpty()) {
+            query.append("and stackId in (");
+            fillSqlWithListValues(query, args, localStackIds);
+            query.append(") ");
+        }
 
         if (!filter.getLabels().isEmpty()) {
             query.append("and (exists(select 1 from joincardwithlabel j where c.localId = cardId and labelId in (");
-            fillSqlWithListValues(query, args, filter.getLabels());
+            fillSqlWithEntityListValues(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)) ");
@@ -236,7 +272,7 @@ public class DataBaseAdapter {
 
         if (!filter.getUsers().isEmpty()) {
             query.append("and (exists(select 1 from joincardwithuser j where c.localId = cardId and userId in (");
-            fillSqlWithListValues(query, args, filter.getUsers());
+            fillSqlWithEntityListValues(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)) ");
@@ -247,6 +283,19 @@ public class DataBaseAdapter {
             query.append("and not exists(select 1 from joincardwithuser j where c.localId = cardId and j.status<>3) ");
         }
 
+        if (!filter.getProjects().isEmpty()) {
+            query.append("and (exists(select 1 from joincardwithproject j where c.localId = cardId and projectId in (");
+            fillSqlWithEntityListValues(query, args, filter.getProjects());
+            query.append(") and j.status<>3) ");
+            if (filter.isNoAssignedProject()) {
+                query.append("or not exists(select 1 from joincardwithproject j where c.localId = cardId and j.status<>3)) ");
+            } else {
+                query.append(") ");
+            }
+        } else if (filter.isNoAssignedProject()) {
+            query.append("and not exists(select 1 from joincardwithproject j where c.localId = cardId and j.status<>3) ");
+        }
+
         if (filter.getDueType() != EDueType.NO_FILTER) {
             switch (filter.getDueType()) {
                 case NO_DUE:
@@ -265,13 +314,13 @@ public class DataBaseAdapter {
                     query.append("and datetime(c.duedate/1000, 'unixepoch', 'localtime') between datetime('now', 'localtime') and datetime('now', '+30 day', 'localtime')");
                     break;
                 default:
-                    throw new IllegalArgumentException("Xou need to add your new EDueType value\"" + filter.getDueType() + "\" here!");
+                    throw new IllegalArgumentException("You need to add your new EDueType value\"" + filter.getDueType() + "\" here!");
             }
         }
         if (filter.getArchiveStatus() != FilterInformation.EArchiveStatus.ALL) {
             query.append(" and c.archived = " + (filter.getArchiveStatus() == FilterInformation.EArchiveStatus.ARCHIVED ? 1 : 0));
         }
-        query.append(" and status<>3 order by `order`, createdAt asc;");
+        query.append(" and status<>3 order by accountId asc, stackId asc, `order`, createdAt asc;");
         return new SimpleSQLiteQuery(query.toString(), args.toArray());
     }
 
@@ -283,7 +332,25 @@ public class DataBaseAdapter {
     @WorkerThread
     public long createUser(long accountId, User user) {
         user.setAccountId(accountId);
-        return db.getUserDao().insert(user);
+        long newId = db.getUserDao().insert(user);
+        new Thread(() -> {
+            Account account = db.getAccountDao().getAccountByIdDirectly(accountId);
+            if (account.getUserName().equals(user.getUid())) {
+                for (FilterWidget widget : getFilterWidgetsByType(EWidgetType.UPCOMING_WIDGET)) {
+                    for (FilterWidgetAccount widgetAccount : widget.getAccounts()) {
+                        if (widgetAccount.getAccountId() == accountId && widgetAccount.getUsers().isEmpty()) {
+                            FilterWidgetUser u = new FilterWidgetUser();
+                            u.setFilterAccountId(widgetAccount.getId());
+                            u.setUserId(newId);
+                            widgetAccount.getUsers().add(u);
+                            updateFilterWidgetDirectly(widget);
+                        }
+                    }
+                }
+            }
+            notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.USER, newId);
+        }).start();
+        return newId;
     }
 
     @WorkerThread
@@ -291,6 +358,7 @@ public class DataBaseAdapter {
         markAsEditedIfNeeded(user, setStatus);
         user.setAccountId(accountId);
         db.getUserDao().update(user);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.USER, user.getLocalId());
     }
 
     @AnyThread
@@ -306,7 +374,9 @@ public class DataBaseAdapter {
     @WorkerThread
     public long createLabelDirectly(long accountId, @NonNull Label label) {
         label.setAccountId(accountId);
-        return db.getLabelDao().insert(label);
+        long newId = db.getLabelDao().insert(label);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.LABEL, newId);
+        return newId;
     }
 
     public void createJoinCardWithLabel(long localLabelId, long localCardId) {
@@ -319,15 +389,15 @@ public class DataBaseAdapter {
             // readded!
             existing.setStatusEnum(DBStatus.LOCAL_EDITED);
             db.getJoinCardWithLabelDao().update(existing);
+            notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.LABEL, existing.getLabelId());
         } else {
             JoinCardWithLabel join = new JoinCardWithLabel();
             join.setCardId(localCardId);
             join.setLabelId(localLabelId);
             join.setStatus(status.getId());
             db.getJoinCardWithLabelDao().insert(join);
+            notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.LABEL, join.getLabelId());
         }
-
-
     }
 
     public void deleteJoinedLabelsForCard(long localCardId) {
@@ -336,10 +406,12 @@ public class DataBaseAdapter {
 
     public void deleteJoinedLabelForCard(long localCardId, long localLabelId) {
         db.getJoinCardWithLabelDao().setDbStatus(localCardId, localLabelId, DBStatus.LOCAL_DELETED.getId());
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.LABEL, localLabelId);
     }
 
     public void deleteJoinedUserForCard(long localCardId, long localUserId) {
         db.getJoinCardWithUserDao().setDbStatus(localCardId, localUserId, DBStatus.LOCAL_DELETED.getId());
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.USER, localUserId);
     }
 
     public void deleteJoinedLabelForCardPhysically(long localCardId, long localLabelId) {
@@ -360,6 +432,7 @@ public class DataBaseAdapter {
             // readded!
             existing.setStatusEnum(DBStatus.LOCAL_EDITED);
             db.getJoinCardWithUserDao().update(existing);
+            notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.USER, localUserId);
         } else if (existing != null) {
             return;
         } else {
@@ -368,6 +441,7 @@ public class DataBaseAdapter {
             join.setUserId(localUserId);
             join.setStatus(status.getId());
             db.getJoinCardWithUserDao().insert(join);
+            notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.USER, localUserId);
         }
     }
 
@@ -411,11 +485,13 @@ public class DataBaseAdapter {
     public void updateLabel(Label label, boolean setStatus) {
         markAsEditedIfNeeded(label, setStatus);
         db.getLabelDao().update(label);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.LABEL, label.getLocalId());
     }
 
     public void deleteLabel(Label label, boolean setStatus) {
         markAsDeletedIfNeeded(label, setStatus);
         db.getLabelDao().update(label);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.LABEL, label.getLocalId());
     }
 
     public void deleteLabelPhysically(Label label) {
@@ -425,12 +501,23 @@ public class DataBaseAdapter {
     public WrappedLiveData<Account> createAccount(Account account) {
         return LiveDataHelper.wrapInLiveData(() -> {
             long id = db.getAccountDao().insert(account);
+
+            new Thread(() -> {
+                DeckLog.verbose("Adding new created", Account.class.getSimpleName(), " with ", id, " to all instances of ", EWidgetType.UPCOMING_WIDGET.name());
+                for (FilterWidget widget : getFilterWidgetsByType(EWidgetType.UPCOMING_WIDGET)) {
+                    widget.getAccounts().add(new FilterWidgetAccount(id, false));
+                    updateFilterWidgetDirectly(widget);
+                }
+                notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.ACCOUNT, id);
+            }).start();
             return readAccountDirectly(id);
         });
     }
 
     public void deleteAccount(long id) {
         db.getAccountDao().deleteById(id);
+        notifyAllWidgets();
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.ACCOUNT, id);
     }
 
     public void updateAccount(Account account) {
@@ -474,7 +561,8 @@ public class DataBaseAdapter {
         return LiveDataHelper.wrapInLiveData(() -> {
             board.setAccountId(accountId);
             long id = db.getBoardDao().insert(board);
-            return db.getBoardDao().getBoardByIdDirectly(id);
+            notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.BOARD, id);
+            return db.getBoardDao().getBoardByLocalIdDirectly(id);
 
         });
     }
@@ -482,21 +570,27 @@ public class DataBaseAdapter {
     @WorkerThread
     public long createBoardDirectly(long accountId, @NonNull Board board) {
         board.setAccountId(accountId);
-        return db.getBoardDao().insert(board);
+        long id = db.getBoardDao().insert(board);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.BOARD, id);
+        return id;
     }
 
     public void deleteBoard(Board board, boolean setStatus) {
         markAsDeletedIfNeeded(board, setStatus);
         db.getBoardDao().update(board);
+        notifyAllWidgets();
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.BOARD, board.getLocalId());
     }
 
     public void deleteBoardPhysically(Board board) {
         db.getBoardDao().delete(board);
+        notifyAllWidgets();
     }
 
     public void updateBoard(Board board, boolean setStatus) {
         markAsEditedIfNeeded(board, setStatus);
         db.getBoardDao().update(board);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.BOARD, board.getLocalId());
     }
 
     public LiveData<List<Stack>> getStacksForBoard(long accountId, long localBoardId) {
@@ -516,28 +610,35 @@ public class DataBaseAdapter {
     @WorkerThread
     public long createStack(long accountId, Stack stack) {
         stack.setAccountId(accountId);
-        return db.getStackDao().insert(stack);
+        long id = db.getStackDao().insert(stack);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.STACK, id);
+        return id;
     }
 
     @WorkerThread
     public void deleteStack(Stack stack, boolean setStatus) {
         markAsDeletedIfNeeded(stack, setStatus);
         db.getStackDao().update(stack);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.STACK, stack.getLocalId());
+        notifyAllWidgets();
     }
 
     @WorkerThread
     public void deleteStackPhysically(Stack stack) {
         db.getStackDao().delete(stack);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.STACK, stack.getLocalId());
+        notifyAllWidgets();
     }
 
     @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);
-        }
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.STACK, stack.getLocalId());
+//        if (db.getStackWidgetModelDao().containsStackLocalId(stack.getLocalId())) {
+//            DeckLog.info("Notifying " + StackWidget.class.getSimpleName() + " about card changes for \"" + stack.getTitle() + "\"");
+//            // FIXME StackWidget.notifyDatasetChanged(context);
+//        }
     }
 
     @WorkerThread
@@ -571,6 +672,7 @@ public class DataBaseAdapter {
         long newCardId = db.getCardDao().insert(card);
 
         notifyStackWidgetsIfNeeded(card.getTitle(), card.getStackId());
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.STACK, card.getStackId());
 
         return newCardId;
     }
@@ -595,6 +697,7 @@ public class DataBaseAdapter {
         }
 
         notifyStackWidgetsIfNeeded(card.getTitle(), card.getStackId());
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.STACK, card.getStackId());
     }
 
     @WorkerThread
@@ -608,22 +711,24 @@ public class DataBaseAdapter {
         Long originalStackLocalId = db.getCardDao().getLocalStackIdByLocalCardId(card.getLocalId());
         db.getCardDao().update(card);
         if (db.getSingleCardWidgetModelDao().containsCardLocalId(card.getLocalId())) {
-            DeckLog.info("Notifying " + SingleCardWidget.class.getSimpleName() + " about card changes for \"" + card.getTitle() + "\"");
+            DeckLog.info("Notifying", SingleCardWidget.class.getSimpleName(), "about card changes for", card.getTitle());
             SingleCardWidget.notifyDatasetChanged(context);
         }
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.STACK, originalStackLocalId);
         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);
-        }
+//        if (db.getStackWidgetModelDao().containsStackLocalId(affectedStackIds)) {
+//            DeckLog.info("Notifying " + StackWidget.class.getSimpleName() + " about card changes for \"" + cardTitle + "\"");
+//            // FIXME StackWidget.notifyDatasetChanged(context);
+//        }
     }
 
     @WorkerThread
     public long createAccessControl(long accountId, @NonNull AccessControl entity) {
         entity.setAccountId(accountId);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.ACCOUNT, accountId);
         return db.getAccessControlDao().insert(entity);
     }
 
@@ -642,6 +747,7 @@ public class DataBaseAdapter {
 
     public void updateAccessControl(AccessControl entity, boolean setStatus) {
         markAsEditedIfNeeded(entity, setStatus);
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.ACCOUNT, entity.getAccountId());
         db.getAccessControlDao().update(entity);
     }
 
@@ -652,6 +758,7 @@ public class DataBaseAdapter {
         } else {
             db.getAccessControlDao().delete(entity);
         }
+        notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.ACCOUNT, entity.getAccountId());
     }
 
     public LiveData<FullBoard> getFullBoardById(Long accountId, Long localId) {
@@ -660,7 +767,7 @@ public class DataBaseAdapter {
 
     @WorkerThread
     public Board getBoardByLocalIdDirectly(long localId) {
-        return db.getBoardDao().getBoardByIdDirectly(localId);
+        return db.getBoardDao().getBoardByLocalIdDirectly(localId);
     }
 
     public LiveData<User> getUserByLocalId(long accountId, long localId) {
@@ -818,6 +925,11 @@ public class DataBaseAdapter {
     }
 
     @WorkerThread
+    public Long getBoardLocalIdByLocalCardIdDirectly(long localCardId) {
+        return db.getBoardDao().getBoardLocalIdByLocalCardIdDirectly(localCardId);
+    }
+
+    @WorkerThread
     public FullBoard getFullBoardByLocalCardIdDirectly(long localCardId) {
         return db.getBoardDao().getFullBoardByLocalCardIdDirectly(localCardId);
     }
@@ -1038,24 +1150,224 @@ public class DataBaseAdapter {
         db.getSingleCardWidgetModelDao().delete(model);
     }
 
-    public long createStackWidget(int appWidgetId, long accountId, long stackId, boolean darkTheme) {
+    public void 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);
+//        db.getStackWidgetModelDao().insert(model);
     }
 
     public StackWidgetModel getStackWidgetModelDirectly(int appWidgetId) {
-        return db.getStackWidgetModelDao().getStackWidgetByAppWidgetIdDirectly(appWidgetId);
+//        return db.getStackWidgetModelDao().getStackWidgetByAppWidgetIdDirectly(appWidgetId);
+        return null;
+    }
+
+    public int createFilterWidgetDirectly(@NonNull FilterWidget filterWidget) {
+        db.getFilterWidgetDao().insert(filterWidget);
+        insertFilterWidgetDecendants(filterWidget);
+        return filterWidget.getId();
+    }
+
+    private void insertFilterWidgetDecendants(FilterWidget filterWidget) {
+        long widgetId = filterWidget.getId();
+        for (FilterWidgetAccount account : filterWidget.getAccounts()) {
+            account.setFilterWidgetId(widgetId);
+            long accountId = db.getFilterWidgetAccountDao().insert(account);
+            for (FilterWidgetUser user : account.getUsers()) {
+                user.setFilterAccountId(accountId);
+                db.getFilterWidgetUserDao().insert(user);
+            }
+            for (FilterWidgetProject project : account.getProjects()) {
+                project.setFilterAccountId(accountId);
+                db.getFilterWidgetProjectDao().insert(project);
+            }
+            for (FilterWidgetBoard board : account.getBoards()) {
+                board.setFilterAccountId(accountId);
+                long boardId = db.getFilterWidgetBoardDao().insert(board);
+                for (FilterWidgetStack stack : board.getStacks()) {
+                    stack.setFilterBoardId(boardId);
+                    db.getFilterWidgetStackDao().insert(stack);
+                }
+                for (FilterWidgetLabel label : board.getLabels()) {
+                    label.setFilterBoardId(boardId);
+                    db.getFilterWidgetLabelDao().insert(label);
+                }
+            }
+        }
+        for (FilterWidgetSort sort : filterWidget.getSorts()) {
+            sort.setFilterWidgetId(widgetId);
+            db.getFilterWidgetSortDao().insert(sort);
+        }
+    }
+
+    public void deleteFilterWidgetDirectly(Integer filterWidgetId) {
+        db.getFilterWidgetDao().delete(filterWidgetId);
+    }
+
+    public void updateFilterWidgetDirectly(FilterWidget filterWidget) {
+        db.getFilterWidgetSortDao().deleteByFilterWidgetId(filterWidget.getId());
+        db.getFilterWidgetAccountDao().deleteByFilterWidgetId(filterWidget.getId());
+        db.getFilterWidgetDao().update(filterWidget);
+        insertFilterWidgetDecendants(filterWidget);
+    }
+
+    public FilterWidget getFilterWidgetByIdDirectly(Integer filterWidgetId) {
+        FilterWidget filterWidget = db.getFilterWidgetDao().getFilterWidgetByIdDirectly(filterWidgetId);
+        if (filterWidget == null) {
+            throw new NoSuchElementException("No widget with id " + filterWidgetId + " configured.");
+        }
+        filterWidget.setSorts(db.getFilterWidgetSortDao().getFilterWidgetSortByFilterWidgetIdDirectly(filterWidgetId));
+        filterWidget.setAccounts(db.getFilterWidgetAccountDao().getFilterWidgetAccountsByFilterWidgetIdDirectly(filterWidgetId));
+        for (FilterWidgetAccount account : filterWidget.getAccounts()) {
+            account.setBoards(db.getFilterWidgetBoardDao().getFilterWidgetBoardsByFilterWidgetAccountIdDirectly(account.getId()));
+            account.setUsers(db.getFilterWidgetUserDao().getFilterWidgetUsersByFilterWidgetAccountIdDirectly(account.getId()));
+            account.setProjects(db.getFilterWidgetProjectDao().getFilterWidgetProjectsByFilterWidgetAccountIdDirectly(account.getId()));
+            for (FilterWidgetBoard board : account.getBoards()) {
+                board.setLabels(db.getFilterWidgetLabelDao().getFilterWidgetLabelsByFilterWidgetBoardIdDirectly(board.getId()));
+                board.setStacks(db.getFilterWidgetStackDao().getFilterWidgetStacksByFilterWidgetBoardIdDirectly(board.getId()));
+            }
+        }
+
+        return filterWidget;
+    }
+
+    public void notifyFilterWidgetsAboutChangedEntity(@NonNull FilterWidget.EChangedEntityType type, Long entityId) {
+        new Thread(() -> {
+            final List<EWidgetType> widgetTypesToNotify = db.getFilterWidgetDao().getChangedListTypesByEntity(type.toString(), entityId);
+            for (EWidgetType t : widgetTypesToNotify) {
+                DeckLog.info("Notifying", t.getWidgetClass().getSimpleName(), "about entity change:", type.name(), "with ID", entityId);
+                context.sendBroadcast(new Intent(context, t.getWidgetClass()).setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE));
+            }
+        }).start();
+    }
+
+    public List<FilterWidgetCard> getCardsForFilterWidget(Integer filterWidgetId) {
+        FilterWidget filterWidget = getFilterWidgetByIdDirectly(filterWidgetId);
+        FilterInformation filter = new FilterInformation();
+        Set<FullCard> cardsResult = new HashSet<>();
+        if (filterWidget.getDueType() != null) {
+            filter.setDueType(filterWidget.getDueType());
+        } else filter.setDueType(EDueType.NO_FILTER);
+
+        if (filterWidget.getAccounts().isEmpty()) {
+            cardsResult.addAll(db.getCardDao().getFilteredFullCardsForStackDirectly(getQueryForFilter(filter, null, null)));
+        } else {
+            for (FilterWidgetAccount account : filterWidget.getAccounts()) {
+                filter.setNoAssignedUser(account.isIncludeNoUser());
+                List<User> users = new ArrayList<>();
+                if (!account.getUsers().isEmpty()) {
+                    for (FilterWidgetUser user : account.getUsers()) {
+                        User u = new User();
+                        u.setLocalId(user.getUserId());
+                        users.add(u);
+                    }
+                }
+                filter.setUsers(users);
+                filter.setNoAssignedProject(account.isIncludeNoProject());
+                List<OcsProject> projects = new ArrayList<>();
+                if (!account.getProjects().isEmpty()) {
+                    for (FilterWidgetProject project : account.getProjects()) {
+                        OcsProject u = new OcsProject();
+                        u.setLocalId(project.getProjectId());
+                        projects.add(u);
+                    }
+                }
+                filter.setProjects(projects);
+                if (!account.getBoards().isEmpty()) {
+                    for (FilterWidgetBoard board : account.getBoards()) {
+                        filter.setNoAssignedLabel(board.isIncludeNoLabel());
+                        List<Long> stacks;
+                        for (FilterWidgetLabel label : board.getLabels()) {
+                            Label l = new Label();
+                            l.setLocalId(label.getLabelId());
+                            filter.addLabel(l);
+                        }
+                        if (board.getStacks().isEmpty()) {
+                            stacks = db.getStackDao().getLocalStackIdsByLocalBoardIdDirectly(board.getBoardId());
+                        } else {
+                            stacks = new ArrayList<>();
+                            for (FilterWidgetStack stack : board.getStacks()) {
+                                stacks.add(stack.getStackId());
+                            }
+                        }
+                        cardsResult.addAll(db.getCardDao().getFilteredFullCardsForStackDirectly(getQueryForFilter(filter, Collections.singletonList(account.getAccountId()), stacks)));
+                    }
+                } else {
+                    cardsResult.addAll(db.getCardDao().getFilteredFullCardsForStackDirectly(getQueryForFilter(filter, Collections.singletonList(account.getAccountId()), null)));
+                }
+            }
+        }
+
+        handleWidgetTypeExtras(filterWidget, cardsResult);
+
+        filterRelationsForCard(cardsResult);
+
+        List<FilterWidgetCard> result = new ArrayList<>(cardsResult.size());
+        Map<Long, Board> boardCache = new HashMap<>();
+        Map<Long, Stack> stackCache = new HashMap<>();
+        for (FullCard fullCard : cardsResult) {
+            Long stackId = fullCard.getCard().getStackId();
+            Stack stack = stackCache.get(stackId);
+            if (stack == null) {
+                stack = db.getStackDao().getStackByLocalIdDirectly(stackId);
+                stackCache.put(stackId, stack);
+            }
+
+            Board board = boardCache.get(stack.getBoardId());
+            if (board == null) {
+                board = db.getBoardDao().getBoardByLocalIdDirectly(stackId);
+                boardCache.put(stackId, board);
+            }
+            result.add(new FilterWidgetCard(fullCard, stack, board));
+        }
+        return result;
+    }
+
+    private void handleWidgetTypeExtras(FilterWidget filterWidget, Collection<FullCard> cardsResult) {
+        if (filterWidget.getWidgetType() == EWidgetType.UPCOMING_WIDGET) {
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/819 "no due" cards are only shown if they are on a shared board
+            for (FullCard fullCard : new ArrayList<>(cardsResult)) {
+                if (fullCard.getCard().getDueDate() == null && !db.getStackDao().isStackOnSharedBoardDirectly(fullCard.getCard().getStackId())) {
+                    cardsResult.remove(fullCard);
+                }
+            }
+            List<Long> accountIds = null;
+            if (!filterWidget.getAccounts().isEmpty()) {
+                accountIds = filterWidget.getAccounts().stream().map(FilterWidgetAccount::getAccountId).collect(Collectors.toList());
+            }
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/822 exclude archived cards and boards
+            List<Long> archivedStacks = db.getStackDao().getLocalStackIdsInArchivedBoardsByAccountIdsDirectly(accountIds);
+            for (Long archivedStack : archivedStacks) {
+                List<FullCard> archivedCards = cardsResult.stream()
+                        .filter(c -> c.getCard().isArchived() || archivedStack.equals(c.getCard().getStackId()))
+                        .collect(Collectors.toList());
+                cardsResult.removeAll(archivedCards);
+            }
+            // https://github.com/stefan-niedermann/nextcloud-deck/issues/800 all cards within non-shared boards need to be included
+            cardsResult.addAll(db.getCardDao().getFullCardsForNonSharedBoardsWithDueDateForUpcomingCardsWidgetDirectly(accountIds));
+        }
+    }
+
+    public List<FilterWidget> getFilterWidgetsByType(EWidgetType type) {
+        List<Integer> ids = db.getFilterWidgetDao().getFilterWidgetIdsByType(type.getId());
+        List<FilterWidget> widgets = new ArrayList<>(ids.size());
+        for (Integer id : ids) {
+            widgets.add(getFilterWidgetByIdDirectly(id));
+        }
+        return widgets;
+    }
+
+    public boolean filterWidgetExists(int id) {
+        return db.getFilterWidgetDao().filterWidgetExists(id);
     }
 
     public void deleteStackWidget(int appWidgetId) {
         StackWidgetModel model = new StackWidgetModel();
         model.setAppWidgetId(appWidgetId);
-        db.getStackWidgetModelDao().delete(model);
+//        db.getStackWidgetModelDao().delete(model);
     }
 
     public LiveData<List<Account>> readAccountsForHostWithReadAccessToBoard(String host, long boardRemoteId) {
@@ -1119,8 +1431,20 @@ public class DataBaseAdapter {
                 assignment.setStatus(DBStatus.UP_TO_DATE.getId());
                 assignment.setCardId(card.getLocalId());
                 assignment.setProjectId(localProjectId);
-                db.getJoinCardWithOcsProjectDao().insert(assignment);
+                long id = db.getJoinCardWithOcsProjectDao().insert(assignment);
+                notifyFilterWidgetsAboutChangedEntity(FilterWidget.EChangedEntityType.PROJECT, id);
             }
         }
     }
+
+    private void notifyAllWidgets() {
+        SingleCardWidget.notifyDatasetChanged(context);
+        /// FIXME StackWidget.notifyDatasetChanged(context);
+//        UpcomingWidget.notifyDatasetChanged(context);
+    }
+
+    @ColorInt
+    public Integer getBoardColorDirectly(long accountId, long localBoardId) {
+        return db.getBoardDao().getBoardColorByLocalIdDirectly(accountId, localBoardId);
+    }
 }
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 a491946ed..6f7ba45e0 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
@@ -1,21 +1,14 @@
 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;
 import androidx.room.Room;
 import androidx.room.RoomDatabase;
 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;
@@ -32,8 +25,6 @@ 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;
@@ -42,8 +33,17 @@ 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.filter.FilterWidget;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetAccount;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetBoard;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetLabel;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetProject;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetSort;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetStack;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetUser;
 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.converter.DateTypeConverter;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.converter.EnumConverter;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.AccessControlDao;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.AccountDao;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.ActivityDao;
@@ -67,7 +67,36 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.projects.Jo
 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;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter.FilterWidgetAccountDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter.FilterWidgetBoardDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter.FilterWidgetDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter.FilterWidgetLabelDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter.FilterWidgetProjectDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter.FilterWidgetSortDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter.FilterWidgetStackDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter.FilterWidgetUserDao;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_10_11;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_11_12;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_12_13;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_13_14;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_14_15;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_15_16;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_16_17;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_17_18;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_18_19;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_19_20;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_20_21;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_21_22;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_22_23;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_23_24;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_24_25;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_25_26;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_26_27;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_27_28;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_28_29;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_29_30;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_8_9;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration.Migration_9_10;
 
 @Database(
         entities = {
@@ -89,316 +118,34 @@ import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.Sta
                 DeckComment.class,
                 Mention.class,
                 SingleCardWidgetModel.class,
-                StackWidgetModel.class,
                 OcsProject.class,
                 OcsProjectResource.class,
                 JoinCardWithProject.class,
                 UserInGroup.class,
                 UserInBoard.class,
+                FilterWidget.class,
+                FilterWidgetAccount.class,
+                FilterWidgetBoard.class,
+                FilterWidgetStack.class,
+                FilterWidgetLabel.class,
+                FilterWidgetUser.class,
+                FilterWidgetProject.class,
+                FilterWidgetSort.class,
         },
         exportSchema = false,
-        version = 23
+        version = 30
 )
-@TypeConverters({DateTypeConverter.class})
+@TypeConverters({DateTypeConverter.class, EnumConverter.class})
 public abstract class DeckDatabase extends RoomDatabase {
 
-
     private static final String DECK_DB_NAME = "NC_DECK_DB.db";
     private static volatile DeckDatabase instance;
 
-    private static final Migration MIGRATION_8_9 = new Migration(8, 9) {
-        @Override
-        public void migrate(SupportSQLiteDatabase database) {
-            database.execSQL("CREATE TABLE `DeckComment` (`localId` INTEGER PRIMARY KEY AUTOINCREMENT, `accountId` INTEGER NOT NULL, `id` INTEGER, `status` INTEGER NOT NULL, `lastModified` INTEGER, `lastModifiedLocal` INTEGER, `objectId` INTEGER, `actorType` TEXT, `creationDateTime` INTEGER, `actorId` TEXT, `actorDisplayName` TEXT, `message` TEXT, FOREIGN KEY(`objectId`) REFERENCES `Card`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE )");
-            database.execSQL("CREATE TABLE `Mention` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `commentId` INTEGER, `mentionId` TEXT, `mentionType` TEXT, `mentionDisplayName` TEXT, FOREIGN KEY(`commentId`) REFERENCES `DeckComment`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE )");
-            database.execSQL("CREATE INDEX `index_DeckComment_accountId` ON `DeckComment` (`accountId`)");
-            database.execSQL("CREATE INDEX `comment_accID` ON `DeckComment` (`accountId`)");
-            database.execSQL("CREATE UNIQUE INDEX `index_DeckComment_accountId_id` ON `DeckComment` (`accountId`, `id`)");
-            database.execSQL("CREATE INDEX `index_DeckComment_id` ON `DeckComment` (`id`)");
-            database.execSQL("CREATE INDEX `index_DeckComment_lastModifiedLocal` ON `DeckComment` (`lastModifiedLocal`)");
-            database.execSQL("CREATE INDEX `index_DeckComment_objectId` ON `DeckComment` (`objectId`)");
-            database.execSQL("CREATE INDEX `index_Mention_commentId` ON `Mention` (`commentId`)");
-        }
-    };
-
-    private static final Migration MIGRATION_9_10 = new Migration(9, 10) {
-        @Override
-        public void migrate(SupportSQLiteDatabase database) {
-            database.execSQL("ALTER TABLE `Account` ADD `color` TEXT NOT NULL DEFAULT '#0082c9'");
-            database.execSQL("ALTER TABLE `Account` ADD `textColor` TEXT NOT NULL DEFAULT '#ffffff'");
-            database.execSQL("ALTER TABLE `Account` ADD `serverDeckVersion` TEXT NOT NULL DEFAULT '0.6.4'");
-            database.execSQL("ALTER TABLE `Account` ADD `maintenanceEnabled` INTEGER NOT NULL DEFAULT 0");
-        }
-    };
-
-    private static final Migration MIGRATION_10_11 = new Migration(10, 11) {
-        @Override
-        public void migrate(SupportSQLiteDatabase database) {
-            // replace duplicates with the server-known ones
-            Cursor duplucatesCursor = database.query("SELECT boardId, title, count(*) FROM Label group by boardid, title having count(*) > 1");
-            if (duplucatesCursor != null && duplucatesCursor.moveToFirst()) {
-                do {
-                    long boardId = duplucatesCursor.getLong(0);
-                    String title = duplucatesCursor.getString(1);
-                    Cursor singleDuplicateCursor = database.query("select localId from Label where boardId = ? and title = ? order by id desc", new Object[]{boardId, title});
-                    if (singleDuplicateCursor != null && singleDuplicateCursor.moveToFirst()) {
-                        long idToUse = -1;
-                        do {
-                            if (idToUse < 0) {
-                                // desc order -> first one is the one with remote ID or a random one. keep this one.
-                                idToUse = singleDuplicateCursor.getLong(0);
-                                continue;
-                            }
-                            long idToReplace = singleDuplicateCursor.getLong(0);
-                            Cursor cardsAssignedToDuplicateCursor = database.query("select cardId, exists(select 1 from JoinCardWithLabel ij where ij.labelId = ? and ij.cardId = cardId) " +
-                                    "from JoinCardWithLabel where labelId = ?", new Object[]{idToUse, idToReplace});
-                            if (cardsAssignedToDuplicateCursor != null && cardsAssignedToDuplicateCursor.moveToFirst()) {
-                                do {
-                                    long cardId = cardsAssignedToDuplicateCursor.getLong(0);
-                                    boolean hasDestinationLabelAssigned = cardsAssignedToDuplicateCursor.getInt(1) > 0;
-                                    database.execSQL("DELETE FROM JoinCardWithLabel where labelId = ? and cardId = ?", new Object[]{idToReplace, cardId});
-
-                                    if (!hasDestinationLabelAssigned) {
-                                        database.execSQL("INSERT INTO JoinCardWithLabel (status,labelId,cardId) VALUES (?, ?, ?)", new Object[]{DBStatus.LOCAL_EDITED.getId(), idToUse, cardId});
-                                    }
-                                } while (cardsAssignedToDuplicateCursor.moveToNext());
-                            }
-                            database.execSQL("DELETE FROM Label where localId = ?", new Object[]{idToReplace});
-                        } while (singleDuplicateCursor.moveToNext());
-                    }
-                } while (duplucatesCursor.moveToNext());
-            }
-//            database.execSQL("DELETE FROM Label WHERE id IS NULL AND EXISTS(SELECT 1 FROM Label il WHERE il.boardId = boardId AND il.title = title AND id IS NOT NULL)");
-            database.execSQL("CREATE UNIQUE INDEX idx_label_title_unique ON Label(boardId, title)");
-        }
-    };
-
-    private static final Migration MIGRATION_11_12 = new Migration(11, 12) {
-        @Override
-        public void migrate(SupportSQLiteDatabase database) {
-            database.execSQL("CREATE TABLE `SingleCardWidgetModel` (`widgetId` INTEGER PRIMARY KEY, `accountId` INTEGER, `boardId` INTEGER, `cardId` INTEGER, FOREIGN KEY(`accountId`) REFERENCES `Account`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE, FOREIGN KEY(`boardId`) REFERENCES `Board`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE, FOREIGN KEY(`cardId`) REFERENCES `Card`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE )");
-            database.execSQL("CREATE INDEX `index_SingleCardWidgetModel_cardId` ON `SingleCardWidgetModel` (`cardId`)");
-        }
-    };
-
-    private static final Migration MIGRATION_12_13 = new Migration(12, 13) {
-        @Override
-        public void migrate(SupportSQLiteDatabase database) {
-            database.execSQL("CREATE INDEX `idx_cardWidgetModel_accountId` ON `SingleCardWidgetModel` (`accountId`)");
-            database.execSQL("CREATE INDEX `idx_cardWidgetModel_boardId` ON `SingleCardWidgetModel` (`boardId`)");
-        }
-    };
-
-    private static final Migration MIGRATION_13_14 = new Migration(13, 14) {
-        @Override
-        public void migrate(SupportSQLiteDatabase database) {
-            database.execSQL("ALTER TABLE `DeckComment` ADD `parentId` INTEGER REFERENCES DeckComment(localId) ON DELETE CASCADE");
-            database.execSQL("CREATE INDEX `idx_comment_parentID` ON DeckComment(parentId)");
-        }
-    };
-
-    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);
-            DeckLog.log("onCreate triggered!!!");
+            DeckLog.info("Database", DECK_DB_NAME, "created.");
             LastSyncUtil.resetAll();
         }
     };
@@ -415,45 +162,28 @@ public abstract class DeckDatabase extends RoomDatabase {
                 context,
                 DeckDatabase.class,
                 DECK_DB_NAME)
-                .addMigrations(MIGRATION_8_9)
-                .addMigrations(MIGRATION_9_10)
-                .addMigrations(MIGRATION_10_11)
-                .addMigrations(MIGRATION_11_12)
-                .addMigrations(MIGRATION_12_13)
-                .addMigrations(MIGRATION_13_14)
-                .addMigrations(new Migration(14, 15) {
-                    @Override
-                    public void migrate(@NonNull SupportSQLiteDatabase database) {
-                        // https://github.com/stefan-niedermann/nextcloud-deck/issues/570
-                        SyncWorker.update(context);
-                        // https://github.com/stefan-niedermann/nextcloud-deck/issues/525
-                        PreferenceManager
-                                .getDefaultSharedPreferences(context)
-                                .edit()
-                                .remove("it.niedermann.nextcloud.deck.theme_text")
-                                .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)
+                .addMigrations(new Migration_8_9())
+                .addMigrations(new Migration_9_10())
+                .addMigrations(new Migration_10_11())
+                .addMigrations(new Migration_11_12())
+                .addMigrations(new Migration_12_13())
+                .addMigrations(new Migration_13_14())
+                .addMigrations(new Migration_14_15(context))
+                .addMigrations(new Migration_15_16())
+                .addMigrations(new Migration_16_17())
+                .addMigrations(new Migration_17_18())
+                .addMigrations(new Migration_18_19())
+                .addMigrations(new Migration_19_20())
+                .addMigrations(new Migration_20_21())
+                .addMigrations(new Migration_21_22(context))
+                .addMigrations(new Migration_22_23())
+                .addMigrations(new Migration_23_24(context))
+                .addMigrations(new Migration_24_25())
+                .addMigrations(new Migration_25_26())
+                .addMigrations(new Migration_26_27())
+                .addMigrations(new Migration_27_28())
+                .addMigrations(new Migration_28_29())
+                .addMigrations(new Migration_29_30(context))
                 .fallbackToDestructiveMigration()
                 .addCallback(ON_CREATE_CALLBACK)
                 .build();
@@ -495,8 +225,6 @@ public abstract class DeckDatabase extends RoomDatabase {
 
     public abstract SingleCardWidgetModelDao getSingleCardWidgetModelDao();
 
-    public abstract StackWidgetModelDao getStackWidgetModelDao();
-
     public abstract OcsProjectDao getOcsProjectDao();
 
     public abstract OcsProjectResourceDao getOcsProjectResourceDao();
@@ -506,4 +234,21 @@ public abstract class DeckDatabase extends RoomDatabase {
     public abstract UserInGroupDao getUserInGroupDao();
 
     public abstract UserInBoardDao getUserInBoardDao();
+
+    public abstract FilterWidgetDao getFilterWidgetDao();
+
+    public abstract FilterWidgetAccountDao getFilterWidgetAccountDao();
+
+    public abstract FilterWidgetBoardDao getFilterWidgetBoardDao();
+
+    public abstract FilterWidgetStackDao getFilterWidgetStackDao();
+
+    public abstract FilterWidgetLabelDao getFilterWidgetLabelDao();
+
+    public abstract FilterWidgetUserDao getFilterWidgetUserDao();
+
+    public abstract FilterWidgetProjectDao getFilterWidgetProjectDao();
+
+    public abstract FilterWidgetSortDao getFilterWidgetSortDao();
+
 }
\ No newline at end of file
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/converter/DateTypeConverter.java
index f6811e033..a39a4a665 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/converter/DateTypeConverter.java
@@ -1,4 +1,4 @@
-package it.niedermann.nextcloud.deck.persistence.sync.adapters.db;
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.converter;
 
 import androidx.room.TypeConverter;
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/converter/EnumConverter.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/converter/EnumConverter.java
new file mode 100644
index 000000000..2cafaa8fe
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/converter/EnumConverter.java
@@ -0,0 +1,67 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.converter;
+
+import androidx.annotation.Nullable;
+import androidx.room.TypeConverter;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.model.enums.EAttachmentType;
+import it.niedermann.nextcloud.deck.model.enums.EDueType;
+import it.niedermann.nextcloud.deck.model.enums.ESortCriteria;
+import it.niedermann.nextcloud.deck.model.widget.filter.EWidgetType;
+
+public class EnumConverter {
+    // #### EWidgetType
+    @TypeConverter
+    public static EWidgetType toWidgetTypeEnum(Integer value) {
+        try {
+            return value == null ? null : EWidgetType.findById(value);
+        } catch (IllegalArgumentException e) {
+            DeckLog.error(EWidgetType.class.getSimpleName(), value, "not found. Falling back to generic", EWidgetType.FILTER_WIDGET);
+            return EWidgetType.FILTER_WIDGET;
+        }
+    }
+
+    @TypeConverter
+    public static Integer fromWidgetTypeEnum(EWidgetType value) {
+        return value == null ? null : value.getId();
+    }
+
+    // #### EDueType
+    @TypeConverter
+    @Nullable
+    public static EDueType toDueTypeEnum(@Nullable Integer value) {
+        return value == null ? null : EDueType.findById(value);
+    }
+
+    @TypeConverter
+    @Nullable
+    public static Integer fromDueTypeEnum(@Nullable EDueType value) {
+        return value == null ? null : value.getId();
+    }
+
+    // #### ESortCriteria
+    @TypeConverter
+    @Nullable
+    public static ESortCriteria toSortCriteriaEnum(@Nullable Integer value) {
+        return value == null ? null : ESortCriteria.findById(value);
+    }
+
+    @TypeConverter
+    @Nullable
+    public static Integer fromSortCriteriaEnum(@Nullable ESortCriteria value) {
+        return value == null ? null : value.getId();
+    }
+
+    // #### EAttachmentType
+    @TypeConverter
+    @Nullable
+    public static EAttachmentType toEAttachmentType(@Nullable String value) {
+        return value == null ? null : EAttachmentType.findByValue(value);
+    }
+
+    @TypeConverter
+    @Nullable
+    public static String fromEAttachmentType(@Nullable EAttachmentType value) {
+        return value == null ? null : value.getValue();
+    }
+}
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 6cb322aa3..89ada6e18 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
@@ -33,7 +33,7 @@ public interface BoardDao extends GenericDao<Board> {
     Board getBoardByRemoteIdDirectly(long accountId, long remoteId);
 
     @Query("SELECT * FROM board WHERE localId = :localId")
-    Board getBoardByIdDirectly(long localId);
+    Board getBoardByLocalIdDirectly(long localId);
 
     @Transaction
     @Query("SELECT * FROM board WHERE accountId = :accountId and id = :remoteId")
@@ -51,10 +51,12 @@ public interface BoardDao extends GenericDao<Board> {
     @Query("SELECT * FROM board WHERE accountId = :accountId and localId = :localId")
     LiveData<FullBoard> getFullBoardById(final long accountId, final long localId);
 
-
-    @Query("SELECT b.* FROM board b JOIN stack s ON s.boardId = b.localId JOIN card c ON c.localId = :localCardId")
+    @Query("SELECT b.* FROM board b JOIN stack s ON s.boardId = b.localId JOIN card c ON s.localId = c.stackId where c.localId = :localCardId")
     Board getBoardByLocalCardIdDirectly(long localCardId);
 
+    @Query("SELECT b.localId FROM board b JOIN stack s ON s.boardId = b.localId JOIN card c ON s.localId = c.stackId where c.localId = :localCardId")
+    Long getBoardLocalIdByLocalCardIdDirectly(long 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);
@@ -66,7 +68,6 @@ public interface BoardDao extends GenericDao<Board> {
     @Query("SELECT * FROM board WHERE accountId = :accountId and archived = 0 and permissionEdit = 1 and (deletedAt = 0 or deletedAt is null) and status <> 3 order by title asc")
     LiveData<List<Board>> getBoardsWithEditPermissionsForAccount(long accountId);
 
-
     @Query("SELECT b.localId " +
             "FROM card c " +
             "inner join stack s on s.localId = c.stackId " +
@@ -79,4 +80,7 @@ public interface BoardDao extends GenericDao<Board> {
 
     @Query("SELECT * FROM board WHERE accountId = :accountId and title = :title")
     Board getBoardForAccountByNameDirectly(long accountId, String title);
+
+    @Query("SELECT b.color FROM board b where b.localId = :localBoardId and b.accountId = :accountId")
+    Integer getBoardColorByLocalIdDirectly(long accountId, long localBoardId);
 }
\ 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 82bdf1b8d..51fbc0d89 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
@@ -85,4 +85,17 @@ public interface CardDao extends GenericDao<Card> {
 
     @Query("SELECT c.stackId FROM card c WHERE  localId = :localCardId")
     Long getLocalStackIdByLocalCardId(Long localCardId);
+
+    @Transaction
+    @Query("SELECT * FROM card c WHERE " +
+            "exists(select 1 from Stack s join Board b on s.boardId = b.localId where s.localId = c.stackId " +
+            "and b.archived = 0 " +
+            "and not exists(select 1 from AccessControl ac where ac.boardId = b.localId and status <> 3)) " +
+            "and dueDate is not null " +
+            "and (coalesce(:accountIds, null) is null or accountId in (:accountIds)) " +
+            "and status <> 3 " +
+            "and archived = 0")
+    List<FullCard> getFullCardsForNonSharedBoardsWithDueDateForUpcomingCardsWidgetDirectly(List<Long> accountIds);
+
+
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/GenericDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/GenericDao.java
index 97e62226d..f6a57a67a 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/GenericDao.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/GenericDao.java
@@ -9,12 +9,15 @@ public interface GenericDao<T> {
     @Insert
     long insert(T entity);
 
+    @SuppressWarnings("unchecked")
     @Insert
     long[] insert(T... entity);
 
+    @SuppressWarnings("unchecked")
     @Update
     void update(T... entity);
 
+    @SuppressWarnings("unchecked")
     @Delete
     void delete(T... entity);
 }
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 feb7e453b..1d2649488 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
@@ -38,6 +38,12 @@ public interface StackDao extends GenericDao<Stack> {
     @Query("SELECT * FROM stack WHERE accountId = :accountId and localId = :localId")
     LiveData<FullStack> getFullStack(long accountId, long localId);
 
+    @Query("SELECT localId FROM stack WHERE accountId = :accountId")
+    List<Long> getLocalStackIdsByAccountIdDirectly(long accountId);
+
+    @Query("SELECT localId FROM stack WHERE boardId = :localBoardId")
+    List<Long> getLocalStackIdsByLocalBoardIdDirectly(long localBoardId);
+
     @Transaction
     @Query("SELECT * FROM stack WHERE accountId = :accountId and boardId = :localBoardId and (status<>1 or id is null or lastModified <> lastModifiedLocal)")
     List<FullStack> getLocallyChangedStacksForBoardDirectly(long accountId, long localBoardId);
@@ -55,4 +61,10 @@ public interface StackDao extends GenericDao<Stack> {
 
     @Query("SELECT coalesce(MAX(`order`), -1) FROM stack s WHERE boardId = :localBoardId")
     Integer getHighestStackOrderInBoard(long localBoardId);
+
+    @Query("SELECT exists(select 1 from Stack s join Board b on s.boardId = b.localId where s.localId = :localStackId and exists(select 1 from AccessControl ac where ac.boardId = b.localId and status <> 3))")
+    boolean isStackOnSharedBoardDirectly(Long localStackId);
+
+    @Query("SELECT s.localId FROM stack s join Board b on s.boardId = b.localId where b.archived <> 0 and b.accountId in (:accountIds)")
+    List<Long> getLocalStackIdsInArchivedBoardsByAccountIdsDirectly(List<Long> accountIds);
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetAccountDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetAccountDao.java
new file mode 100644
index 000000000..9133aa4bc
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetAccountDao.java
@@ -0,0 +1,18 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetAccount;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface FilterWidgetAccountDao extends GenericDao<FilterWidgetAccount> {
+    @Query("DELETE FROM FilterWidgetAccount WHERE filterWidgetId = :filterWidgetId")
+    void deleteByFilterWidgetId (Integer filterWidgetId);
+
+    @Query("select * FROM FilterWidgetAccount WHERE filterWidgetId = :filterWidgetId")
+    List<FilterWidgetAccount> getFilterWidgetAccountsByFilterWidgetIdDirectly(Integer filterWidgetId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetBoardDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetBoardDao.java
new file mode 100644
index 000000000..e71c1b51e
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetBoardDao.java
@@ -0,0 +1,15 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetBoard;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface FilterWidgetBoardDao extends GenericDao<FilterWidgetBoard> {
+    @Query("SELECT * FROM FilterWidgetBoard where filterAccountId = :filterWidgetAccountId")
+    List<FilterWidgetBoard> getFilterWidgetBoardsByFilterWidgetAccountIdDirectly(Long filterWidgetAccountId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetDao.java
new file mode 100644
index 000000000..23dcbea0f
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetDao.java
@@ -0,0 +1,44 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+import androidx.room.Transaction;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.widget.filter.EWidgetType;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidget;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface FilterWidgetDao extends GenericDao<FilterWidget> {
+    @Query("DELETE FROM filterwidget WHERE id = :filterWidgetId")
+    void delete (Integer filterWidgetId);
+
+    @Query("SELECT * FROM FilterWidget where id = :filterWidgetId")
+    FilterWidget getFilterWidgetByIdDirectly(Integer filterWidgetId);
+
+    @Query("SELECT EXISTS (SELECT 1 FROM FilterWidget WHERE id = :filterWidgetId)")
+    boolean filterWidgetExists(int filterWidgetId);
+
+    @Query("SELECT id FROM FilterWidget WHERE widgetType = :type")
+    List<Integer> getFilterWidgetIdsByType(int type);
+
+    @Transaction
+    @Query("SELECT DISTINCT w.widgetType " +
+            "FROM FilterWidget w " +
+            "LEFT JOIN FilterWidgetAccount a ON w.id = a.filterWidgetId " +
+            "LEFT JOIN FilterWidgetBoard b ON a.id = b.filterAccountId " +
+            "LEFT JOIN FilterWidgetStack s ON b.id = s.filterBoardId " +
+            "LEFT JOIN FilterWidgetUser u ON a.id = u.filterAccountId " +
+            "LEFT JOIN FilterWidgetProject p ON a.id = p.filterAccountId " +
+            "LEFT JOIN FilterWidgetLabel l ON b.id = l.filterBoardId " +
+            "WHERE (:changedEntityType = 'ACCOUNT' AND (a.accountId = :localIdOfChangedEntity OR a.accountId IS NULL)) " +
+            "OR (:changedEntityType = 'BOARD' AND (b.boardId = :localIdOfChangedEntity OR b.boardId IS NULL)) " +
+            "OR (:changedEntityType = 'STACK' AND (s.stackId = :localIdOfChangedEntity OR s.stackId IS NULL)) " +
+            "OR (:changedEntityType = 'USER' AND (u.userId = :localIdOfChangedEntity OR u.userId IS NULL)) " +
+            "OR (:changedEntityType = 'PROJECT' AND (p.projectId = :localIdOfChangedEntity OR p.projectId IS NULL)) " +
+            "OR (:changedEntityType = 'LABEL' AND (l.labelId = :localIdOfChangedEntity OR l.labelId IS NULL)) "
+    )
+    List<EWidgetType> getChangedListTypesByEntity(String changedEntityType, Long localIdOfChangedEntity);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetLabelDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetLabelDao.java
new file mode 100644
index 000000000..61ed01545
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetLabelDao.java
@@ -0,0 +1,15 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetLabel;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface FilterWidgetLabelDao extends GenericDao<FilterWidgetLabel> {
+    @Query("SELECT * FROM FilterWidgetLabel where filterBoardId = :filterWidgetBoardId")
+    List<FilterWidgetLabel> getFilterWidgetLabelsByFilterWidgetBoardIdDirectly(Long filterWidgetBoardId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetProjectDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetProjectDao.java
new file mode 100644
index 000000000..4e49684e3
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetProjectDao.java
@@ -0,0 +1,15 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetProject;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface FilterWidgetProjectDao extends GenericDao<FilterWidgetProject> {
+    @Query("SELECT * FROM FilterWidgetProject where filterAccountId = :filterWidgetAccountId")
+    List<FilterWidgetProject> getFilterWidgetProjectsByFilterWidgetAccountIdDirectly(Long filterWidgetAccountId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetSortDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetSortDao.java
new file mode 100644
index 000000000..6aa86a4a3
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetSortDao.java
@@ -0,0 +1,18 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetSort;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface FilterWidgetSortDao extends GenericDao<FilterWidgetSort> {
+    @Query("DELETE FROM FilterWidgetSort WHERE filterWidgetId = :filterWidgetId")
+    void deleteByFilterWidgetId (Integer filterWidgetId);
+
+    @Query("select * FROM FilterWidgetSort WHERE filterWidgetId = :filterWidgetId order by ruleOrder asc")
+    List<FilterWidgetSort> getFilterWidgetSortByFilterWidgetIdDirectly(Integer filterWidgetId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetStackDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetStackDao.java
new file mode 100644
index 000000000..fd79a3ba9
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetStackDao.java
@@ -0,0 +1,15 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetStack;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface FilterWidgetStackDao extends GenericDao<FilterWidgetStack> {
+    @Query("SELECT * FROM FilterWidgetStack where filterBoardId = :filterWidgetBoardId")
+    List<FilterWidgetStack> getFilterWidgetStacksByFilterWidgetBoardIdDirectly(Long filterWidgetBoardId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetUserDao.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetUserDao.java
new file mode 100644
index 000000000..6b44103e9
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/dao/widgets/filter/FilterWidgetUserDao.java
@@ -0,0 +1,15 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.widgets.filter;
+
+import androidx.room.Dao;
+import androidx.room.Query;
+
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetUser;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.dao.GenericDao;
+
+@Dao
+public interface FilterWidgetUserDao extends GenericDao<FilterWidgetUser> {
+    @Query("SELECT * FROM FilterWidgetUser where filterAccountId = :filterWidgetAccountId")
+    List<FilterWidgetUser> getFilterWidgetUsersByFilterWidgetAccountIdDirectly(Long filterWidgetAccountId);
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_10_11.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_10_11.java
new file mode 100644
index 000000000..e50c8a62e
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_10_11.java
@@ -0,0 +1,59 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import android.database.Cursor;
+
+import androidx.annotation.NonNull;
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+import it.niedermann.nextcloud.deck.model.enums.DBStatus;
+
+/**
+ * Removes duplicate labels and ensures uniqueness
+ */
+public class Migration_10_11 extends Migration {
+
+    public Migration_10_11() {
+        super(10, 11);
+    }
+
+    @Override
+    public void migrate(@NonNull SupportSQLiteDatabase database) {
+        // replace duplicates with the server-known ones
+        Cursor duplucatesCursor = database.query("SELECT boardId, title, count(*) FROM Label group by boardid, title having count(*) > 1");
+        if (duplucatesCursor != null && duplucatesCursor.moveToFirst()) {
+            do {
+                long boardId = duplucatesCursor.getLong(0);
+                String title = duplucatesCursor.getString(1);
+                Cursor singleDuplicateCursor = database.query("select localId from Label where boardId = ? and title = ? order by id desc", new Object[]{boardId, title});
+                if (singleDuplicateCursor != null && singleDuplicateCursor.moveToFirst()) {
+                    long idToUse = -1;
+                    do {
+                        if (idToUse < 0) {
+                            // desc order -> first one is the one with remote ID or a random one. keep this one.
+                            idToUse = singleDuplicateCursor.getLong(0);
+                            continue;
+                        }
+                        long idToReplace = singleDuplicateCursor.getLong(0);
+                        Cursor cardsAssignedToDuplicateCursor = database.query("select cardId, exists(select 1 from JoinCardWithLabel ij where ij.labelId = ? and ij.cardId = cardId) " +
+                                "from JoinCardWithLabel where labelId = ?", new Object[]{idToUse, idToReplace});
+                        if (cardsAssignedToDuplicateCursor != null && cardsAssignedToDuplicateCursor.moveToFirst()) {
+                            do {
+                                long cardId = cardsAssignedToDuplicateCursor.getLong(0);
+                                boolean hasDestinationLabelAssigned = cardsAssignedToDuplicateCursor.getInt(1) > 0;
+                                database.execSQL("DELETE FROM JoinCardWithLabel where labelId = ? and cardId = ?", new Object[]{idToReplace, cardId});
+
+                                if (!hasDestinationLabelAssigned) {
+                                    database.execSQL("INSERT INTO JoinCardWithLabel (status,labelId,cardId) VALUES (?, ?, ?)", new Object[]{DBStatus.LOCAL_EDITED.getId(), idToUse, cardId});
+                                }
+                            } while (cardsAssignedToDuplicateCursor.moveToNext());
+                        }
+                        database.execSQL("DELETE FROM Label where localId = ?", new Object[]{idToReplace});
+                    } while (singleDuplicateCursor.moveToNext());
+                }
+            } while (duplucatesCursor.moveToNext());
+        }
+        // database.execSQL("DELETE FROM Label WHERE id IS NULL AND EXISTS(SELECT 1 FROM Label il WHERE il.boardId = boardId AND il.title = title AND id IS NOT NULL)");
+        database.execSQL("CREATE UNIQUE INDEX idx_label_title_unique ON Label(boardId, title)");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_11_12.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_11_12.java
new file mode 100644
index 000000000..acd646f63
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_11_12.java
@@ -0,0 +1,20 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Adds support for the Single note widget
+ */
+public class Migration_11_12 extends Migration {
+
+    public Migration_11_12() {
+        super(11, 12);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("CREATE TABLE `SingleCardWidgetModel` (`widgetId` INTEGER PRIMARY KEY, `accountId` INTEGER, `boardId` INTEGER, `cardId` INTEGER, FOREIGN KEY(`accountId`) REFERENCES `Account`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE, FOREIGN KEY(`boardId`) REFERENCES `Board`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE, FOREIGN KEY(`cardId`) REFERENCES `Card`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE INDEX `index_SingleCardWidgetModel_cardId` ON `SingleCardWidgetModel` (`cardId`)");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_12_13.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_12_13.java
new file mode 100644
index 000000000..8a85f1651
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_12_13.java
@@ -0,0 +1,17 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+public class Migration_12_13 extends Migration {
+
+    public Migration_12_13() {
+        super(12, 13);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("CREATE INDEX `idx_cardWidgetModel_accountId` ON `SingleCardWidgetModel` (`accountId`)");
+        database.execSQL("CREATE INDEX `idx_cardWidgetModel_boardId` ON `SingleCardWidgetModel` (`boardId`)");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_13_14.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_13_14.java
new file mode 100644
index 000000000..dfb8994e8
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_13_14.java
@@ -0,0 +1,20 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Adds support for comment responses
+ */
+public class Migration_13_14 extends Migration {
+
+    public Migration_13_14() {
+        super(13, 14);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("ALTER TABLE `DeckComment` ADD `parentId` INTEGER REFERENCES DeckComment(localId) ON DELETE CASCADE");
+        database.execSQL("CREATE INDEX `idx_comment_parentID` ON DeckComment(parentId)");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_14_15.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_14_15.java
new file mode 100644
index 000000000..dc07a12dd
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_14_15.java
@@ -0,0 +1,35 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import android.content.Context;
+
+import androidx.annotation.NonNull;
+import androidx.preference.PreferenceManager;
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+import it.niedermann.nextcloud.deck.persistence.sync.SyncWorker;
+
+/**
+ * @see <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/570">Reinitializes the background synchronization</a> and
+ * <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/525">cleans up old shared preferences</a>
+ */
+public class Migration_14_15 extends Migration {
+
+    @NonNull
+    private final Context context;
+
+    public Migration_14_15(@NonNull Context context) {
+        super(14, 15);
+        this.context = context;
+    }
+
+    @Override
+    public void migrate(@NonNull SupportSQLiteDatabase database) {
+        SyncWorker.update(context);
+        PreferenceManager
+                .getDefaultSharedPreferences(context)
+                .edit()
+                .remove("it.niedermann.nextcloud.deck.theme_text")
+                .apply();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_15_16.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_15_16.java
new file mode 100644
index 000000000..3dd1a3d61
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_15_16.java
@@ -0,0 +1,23 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Adds support for Stack widget
+ */
+public class Migration_15_16 extends Migration {
+
+    public Migration_15_16() {
+        super(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`)");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_16_17.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_16_17.java
new file mode 100644
index 000000000..f276fe879
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_16_17.java
@@ -0,0 +1,34 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * @see <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/573">Adds support for projects</a>
+ */
+public class Migration_16_17 extends Migration {
+
+    public Migration_16_17() {
+        super(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`)");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_17_18.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_17_18.java
new file mode 100644
index 000000000..f42be42af
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_17_18.java
@@ -0,0 +1,19 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/435">Implement ETags for Capabilities endpoint</a>
+ */
+public class Migration_17_18 extends Migration {
+
+    public Migration_17_18() {
+        super(17, 18);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("ALTER TABLE `Account` ADD `etag` TEXT");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_18_19.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_18_19.java
new file mode 100644
index 000000000..072a11541
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_18_19.java
@@ -0,0 +1,21 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * @see <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/619">Handle unknown project types</a>
+ */
+public class Migration_18_19 extends Migration {
+
+    public Migration_18_19() {
+        super(18, 19);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        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`)");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_19_20.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_19_20.java
new file mode 100644
index 000000000..f6667ec02
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_19_20.java
@@ -0,0 +1,35 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Fixes issues with LDAP users when filtering
+ * https://github.com/stefan-niedermann/nextcloud-deck/issues/492
+ * https://github.com/stefan-niedermann/nextcloud-deck/issues/631
+ */
+public class Migration_19_20 extends Migration {
+
+    public Migration_19_20() {
+        super(19, 20);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        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`)");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_20_21.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_20_21.java
new file mode 100644
index 000000000..36a907b20
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_20_21.java
@@ -0,0 +1,123 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import android.database.Cursor;
+import android.graphics.Color;
+
+import androidx.annotation.ColorInt;
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+import it.niedermann.android.util.ColorUtil;
+
+/**
+ * @see <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/556">Store colors as integer in database</a>
+ */
+public class Migration_20_21 extends Migration {
+
+    public Migration_20_21() {
+        super(20, 21);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        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 int color1;
+                @ColorInt int color2;
+                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 int color1;
+                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 int color1;
+                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});
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_21_22.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_21_22.java
new file mode 100644
index 000000000..768de3c5d
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_21_22.java
@@ -0,0 +1,34 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.database.Cursor;
+
+import androidx.annotation.NonNull;
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * @see <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/715">Migrate from java.util.Date and java.util.Calendar to java.time.*</a>
+ */
+public class Migration_21_22 extends Migration {
+
+    @NonNull
+    private final Context context;
+
+    public Migration_21_22(@NonNull Context context) {
+        super(21, 22);
+        this.context = context;
+    }
+
+    @Override
+    public void migrate(@NonNull SupportSQLiteDatabase database) {
+        final SharedPreferences.Editor lastSyncPref = context.getApplicationContext().getSharedPreferences("it.niedermann.nextcloud.deck.last_sync", Context.MODE_PRIVATE).edit();
+        final Cursor cursor = database.query("select id from `Account`");
+        while (cursor.moveToNext()) {
+            lastSyncPref.remove("lS_" + cursor.getLong(0));
+        }
+        cursor.close();
+        lastSyncPref.apply();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_22_23.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_22_23.java
new file mode 100644
index 000000000..240f14ac1
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_22_23.java
@@ -0,0 +1,30 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * @see <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/359">Implement ETags for synchronization Speed-Up</a>
+ */
+public class Migration_22_23 extends Migration {
+
+    public Migration_22_23() {
+        super(22, 23);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        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");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_23_24.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_23_24.java
new file mode 100644
index 000000000..cd0eb094e
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_23_24.java
@@ -0,0 +1,39 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+
+import androidx.annotation.NonNull;
+import androidx.preference.PreferenceManager;
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+import it.niedermann.nextcloud.deck.R;
+
+/**
+ * <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/392">Dark mode following system default</a>
+ */
+public class Migration_23_24 extends Migration {
+
+    @NonNull
+    private final Context context;
+
+    public Migration_23_24(@NonNull Context context) {
+        super(23, 24);
+        this.context = context;
+    }
+
+    @Override
+    public void migrate(@NonNull SupportSQLiteDatabase database) {
+        final SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
+        final String themePref = context.getString(R.string.pref_key_dark_theme);
+
+        if (sharedPreferences.contains(themePref)) {
+            SharedPreferences.Editor editor = sharedPreferences.edit();
+            final boolean darkTheme = sharedPreferences.getBoolean(themePref, false);
+            editor.remove(themePref);
+            editor.putString(themePref, darkTheme ? context.getString(R.string.pref_value_theme_dark) : context.getString(R.string.pref_value_theme_light));
+            editor.apply();
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_24_25.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_24_25.java
new file mode 100644
index 000000000..6d2bff544
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_24_25.java
@@ -0,0 +1,22 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Reset ETags (comments weren't loading due to bug)
+ */
+public class Migration_24_25 extends Migration {
+
+    public Migration_24_25() {
+        super(24, 25);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("UPDATE `Account` SET `boardsEtag` = NULL");
+        database.execSQL("UPDATE `Board` SET `etag` = NULL");
+        database.execSQL("UPDATE `Stack` SET `etag` = NULL");
+        database.execSQL("UPDATE `Card` SET `etag` = NULL");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_25_26.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_25_26.java
new file mode 100644
index 000000000..37c648d00
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_25_26.java
@@ -0,0 +1,42 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Implement <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/597">Filter widget</a>
+ */
+public class Migration_25_26 extends Migration {
+
+    public Migration_25_26() {
+        super(25, 26);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("CREATE TABLE `FilterWidget` (`id` INTEGER PRIMARY KEY NOT NULL, `title` TEXT, `dueType` INTEGER, `widgetType` INTEGER NOT NULL)");
+        database.execSQL("CREATE TABLE `FilterWidgetAccount` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `filterWidgetId` INTEGER, `accountId` INTEGER, `includeNoUser` INTEGER NOT NULL, `includeNoProject` INTEGER NOT NULL, FOREIGN KEY(`accountId`) REFERENCES `Account`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE , FOREIGN KEY(`filterWidgetId`) REFERENCES `FilterWidget`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE TABLE `FilterWidgetBoard` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `filterAccountId` INTEGER, `boardId` INTEGER, `includeNoLabel` INTEGER NOT NULL, FOREIGN KEY(`boardId`) REFERENCES `Board`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE , FOREIGN KEY(`filterAccountId`) REFERENCES `FilterWidgetAccount`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE TABLE `FilterWidgetLabel` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `filterBoardId` INTEGER, `labelId` INTEGER, FOREIGN KEY(`labelId`) REFERENCES `Label`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE , FOREIGN KEY(`filterBoardId`) REFERENCES `FilterWidgetBoard`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE TABLE `FilterWidgetSort` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `filterWidgetId` INTEGER, `direction` INTEGER NOT NULL, `criteria` INTEGER NOT NULL, `ruleOrder` INTEGER NOT NULL, FOREIGN KEY(`filterWidgetId`) REFERENCES `FilterWidget`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE TABLE `FilterWidgetStack` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `filterBoardId` INTEGER, `stackId` INTEGER, FOREIGN KEY(`stackId`) REFERENCES `Stack`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE , FOREIGN KEY(`filterBoardId`) REFERENCES `FilterWidgetBoard`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE TABLE `FilterWidgetUser` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `filterAccountId` INTEGER, `userId` INTEGER, FOREIGN KEY(`userId`) REFERENCES `User`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE , FOREIGN KEY(`filterAccountId`) REFERENCES `FilterWidgetAccount`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE TABLE `FilterWidgetProject` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `filterAccountId` INTEGER, `projectId` INTEGER, FOREIGN KEY(`projectId`) REFERENCES `OcsProject`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE , FOREIGN KEY(`filterAccountId`) REFERENCES `FilterWidgetAccount`(`id`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE INDEX `index_FilterWidgetAccount_filterWidgetId` ON `FilterWidgetAccount` (`filterWidgetId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetAccount_accountId` ON `FilterWidgetAccount` (`accountId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetBoard_boardId` ON `FilterWidgetBoard` (`boardId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetBoard_filterAccountId` ON `FilterWidgetBoard` (`filterAccountId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetLabel_filterBoardId` ON `FilterWidgetLabel` (`filterBoardId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetLabel_labelId` ON `FilterWidgetLabel` (`labelId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetSort_filterWidgetId` ON `FilterWidgetSort` (`filterWidgetId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetStack_filterBoardId` ON `FilterWidgetStack` (`filterBoardId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetStack_stackId` ON `FilterWidgetStack` (`stackId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetUser_filterAccountId` ON `FilterWidgetUser` (`filterAccountId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetUser_userId` ON `FilterWidgetUser` (`userId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetProject_filterAccountId` ON `FilterWidgetProject` (`filterAccountId`)");
+        database.execSQL("CREATE INDEX `idx_FilterWidgetProject_projectId` ON `FilterWidgetProject` (`projectId`)");
+        database.execSQL("CREATE INDEX `unique_idx_FilterWidgetSort_filterWidgetId_criteria` ON `FilterWidgetSort` (`filterWidgetId`, `criteria`)");
+        database.execSQL("CREATE INDEX `unique_idx_FilterWidgetSort_filterWidgetId_ruleOrder` ON `FilterWidgetSort` (`filterWidgetId`, `ruleOrder`)");
+
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_26_27.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_26_27.java
new file mode 100644
index 000000000..f8e27ec6b
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_26_27.java
@@ -0,0 +1,62 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import android.content.ContentValues;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+import it.niedermann.nextcloud.deck.model.widget.filter.EWidgetType;
+
+/**
+ * @see <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/767">Migrate Stack Widget to Filter Widget infrastructure</a>
+ */
+public class Migration_26_27 extends Migration {
+
+    public Migration_26_27() {
+        super(26, 27);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+
+        Cursor cursor = database.query("select s.localId, s.boardId, s.accountId, w.appWidgetId from `StackWidgetModel` w inner join `Stack` s on s.localId = w.stackId");
+        while (cursor.moveToNext()) {
+            Long localStackId = cursor.getLong(0);
+            Long localBoardId = cursor.getLong(1);
+            Long accountId = cursor.getLong(2);
+            Long filterWidgetId = cursor.getLong(3);
+
+            // widget
+            ContentValues values = new ContentValues();
+            values.put("widgetType", EWidgetType.STACK_WIDGET.getId());
+            values.put("id", filterWidgetId);
+            database.insert("FilterWidget", SQLiteDatabase.CONFLICT_NONE, values);
+
+            // account
+            values = new ContentValues();
+            values.put("filterWidgetId", filterWidgetId);
+            values.put("accountId", accountId);
+            values.put("includeNoUser", false);
+            values.put("includeNoProject", false);
+            long filterWidgetAccountId = database.insert("FilterWidgetAccount", SQLiteDatabase.CONFLICT_NONE, values);
+
+            // board
+            values = new ContentValues();
+            values.put("filterAccountId", filterWidgetAccountId);
+            values.put("boardId", localBoardId);
+            values.put("includeNoLabel", false);
+            long filterWidgetBoardId = database.insert("FilterWidgetBoard", SQLiteDatabase.CONFLICT_NONE, values);
+
+            // stack
+            values = new ContentValues();
+            values.put("filterBoardId", filterWidgetBoardId);
+            values.put("stackId", localStackId);
+            database.insert("FilterWidgetStack", SQLiteDatabase.CONFLICT_NONE, values);
+        }
+
+        // cleanup
+        database.execSQL("DROP TABLE `StackWidgetModel`");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_27_28.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_27_28.java
new file mode 100644
index 000000000..3f588e4f4
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_27_28.java
@@ -0,0 +1,19 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Adds support for new attachment types with Deck server <code>1.3.0</code>
+ */
+public class Migration_27_28 extends Migration {
+
+    public Migration_27_28() {
+        super(27, 28);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("ALTER TABLE `Attachment` ADD COLUMN `fileId` INTEGER");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_28_29.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_28_29.java
new file mode 100644
index 000000000..69c163639
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_28_29.java
@@ -0,0 +1,22 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Reset ETags for cards because <a href="https://github.com/nextcloud/deck/issues/2874">the attachments for this card might not be complete</a>.
+ */
+public class Migration_28_29 extends Migration {
+
+    public Migration_28_29() {
+        super(28, 29);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("UPDATE `Account` SET `boardsEtag` = NULL");
+        database.execSQL("UPDATE `Board` SET `etag` = NULL");
+        database.execSQL("UPDATE `Stack` SET `etag` = NULL");
+        database.execSQL("UPDATE `Card` SET `etag` = NULL");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_29_30.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_29_30.java
new file mode 100644
index 000000000..665fedeb4
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_29_30.java
@@ -0,0 +1,30 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import android.content.Context;
+
+import androidx.annotation.NonNull;
+import androidx.preference.PreferenceManager;
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * <a href="https://github.com/stefan-niedermann/nextcloud-deck/issues/392">Dark mode following system default</a>
+ */
+public class Migration_29_30 extends Migration {
+
+    @NonNull
+    private final Context context;
+
+    public Migration_29_30(@NonNull Context context) {
+        super(29, 30);
+        this.context = context;
+    }
+
+    @Override
+    public void migrate(@NonNull SupportSQLiteDatabase database) {
+        PreferenceManager.getDefaultSharedPreferences(context)
+                .edit()
+                .remove("branding")
+                .apply();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_8_9.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_8_9.java
new file mode 100644
index 000000000..4840dc050
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_8_9.java
@@ -0,0 +1,27 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Adds support for comments
+ */
+public class Migration_8_9 extends Migration {
+
+    public Migration_8_9() {
+        super(8, 9);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("CREATE TABLE `DeckComment` (`localId` INTEGER PRIMARY KEY AUTOINCREMENT, `accountId` INTEGER NOT NULL, `id` INTEGER, `status` INTEGER NOT NULL, `lastModified` INTEGER, `lastModifiedLocal` INTEGER, `objectId` INTEGER, `actorType` TEXT, `creationDateTime` INTEGER, `actorId` TEXT, `actorDisplayName` TEXT, `message` TEXT, FOREIGN KEY(`objectId`) REFERENCES `Card`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE TABLE `Mention` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `commentId` INTEGER, `mentionId` TEXT, `mentionType` TEXT, `mentionDisplayName` TEXT, FOREIGN KEY(`commentId`) REFERENCES `DeckComment`(`localId`) ON UPDATE NO ACTION ON DELETE CASCADE )");
+        database.execSQL("CREATE INDEX `index_DeckComment_accountId` ON `DeckComment` (`accountId`)");
+        database.execSQL("CREATE INDEX `comment_accID` ON `DeckComment` (`accountId`)");
+        database.execSQL("CREATE UNIQUE INDEX `index_DeckComment_accountId_id` ON `DeckComment` (`accountId`, `id`)");
+        database.execSQL("CREATE INDEX `index_DeckComment_id` ON `DeckComment` (`id`)");
+        database.execSQL("CREATE INDEX `index_DeckComment_lastModifiedLocal` ON `DeckComment` (`lastModifiedLocal`)");
+        database.execSQL("CREATE INDEX `index_DeckComment_objectId` ON `DeckComment` (`objectId`)");
+        database.execSQL("CREATE INDEX `index_Mention_commentId` ON `Mention` (`commentId`)");
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_9_10.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_9_10.java
new file mode 100644
index 000000000..59e9200f4
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/adapters/db/migration/Migration_9_10.java
@@ -0,0 +1,22 @@
+package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.migration;
+
+import androidx.room.migration.Migration;
+import androidx.sqlite.db.SupportSQLiteDatabase;
+
+/**
+ * Adds support for account colors, deck server versions and Nextcloud maintenance mode
+ */
+public class Migration_9_10 extends Migration {
+
+    public Migration_9_10() {
+        super(9, 10);
+    }
+
+    @Override
+    public void migrate(SupportSQLiteDatabase database) {
+        database.execSQL("ALTER TABLE `Account` ADD `color` TEXT NOT NULL DEFAULT '#0082c9'");
+        database.execSQL("ALTER TABLE `Account` ADD `textColor` TEXT NOT NULL DEFAULT '#ffffff'");
+        database.execSQL("ALTER TABLE `Account` ADD `serverDeckVersion` TEXT NOT NULL DEFAULT '0.6.4'");
+        database.execSQL("ALTER TABLE `Account` ADD `maintenanceEnabled` INTEGER NOT NULL DEFAULT 0");
+    }
+}
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 003bceb26..df2eac222 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
@@ -1,11 +1,8 @@
 package it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util;
 
-import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.lifecycle.MutableLiveData;
 
-import it.niedermann.nextcloud.deck.DeckLog;
-
 /**
  * Extends a {@link MutableLiveData} with an error state
  *
@@ -29,13 +26,7 @@ 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(locallyCreatedEntity);
+        postValue(null);
     }
 }
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 782b6d951..fa5483b26 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
@@ -35,7 +35,7 @@ public class DataPropagationHelper {
         boolean connected = serverAdapter.hasInternetConnection();
         if (connected) {
             try {
-                provider.createOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(new Account(accountId)) {
+                provider.createOnServer(serverAdapter, dataBaseAdapter, accountId, new IResponseCallback<T>(callback.getAccount()) {
                     @Override
                     public void onResponse(T response) {
                         new Thread(() -> {
@@ -53,11 +53,11 @@ public class DataPropagationHelper {
                     @Override
                     public void onError(Throwable throwable) {
                         super.onError(throwable);
-                        new Thread(() -> callback.onError(throwable, entity)).start();
+                        new Thread(() -> callback.onError(throwable)).start();
                     }
                 }, entity);
             } catch (Throwable t) {
-                callback.onError(t, entity);
+                callback.onError(t);
             }
         } else {
             callback.onResponse(entity);
@@ -90,12 +90,12 @@ public class DataPropagationHelper {
                     public void onError(Throwable throwable) {
                         super.onError(throwable);
                         new Thread(() -> {
-                            callback.onError(throwable, entity);
+                            callback.onError(throwable);
                         }).start();
                     }
                 }, entity);
             } catch (Throwable t) {
-                callback.onError(t, entity);
+                callback.onError(t);
             }
         } else {
             callback.onResponse(entity);
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 17c0de2cf..20421ff1a 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
@@ -27,11 +27,14 @@ public class SyncHelper {
     private long accountId;
     private IResponseCallback<Boolean> responseCallback;
     private final Instant lastSync;
+    private final boolean etagsEnabled;
 
     public SyncHelper(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, Instant lastSync) {
         this.serverAdapter = serverAdapter;
         this.dataBaseAdapter = dataBaseAdapter;
         this.lastSync = lastSync;
+        // check only once per sync
+        this.etagsEnabled = serverAdapter.isEtagsEnabled();
     }
 
     // Sync Server -> App
@@ -45,7 +48,7 @@ public class SyncHelper {
                     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());
+                            DeckLog.error("Skipped null value from server for DataProvider:", provider.getClass().getSimpleName());
                             continue;
                         }
                         entityFromServer.setAccountId(accountId);
@@ -56,10 +59,10 @@ public class SyncHelper {
                         } else {
                             //TODO: how to handle deletes? what about archived?
                             if (existingEntity.getStatus() != DBStatus.UP_TO_DATE.getId()) {
-                                DeckLog.warn("Conflicting changes on entity: " + existingEntity);
+                                DeckLog.warn("Conflicting changes on entity:", existingEntity);
                                 // TODO: what to do?
                             } else {
-                                if (entityFromServer.getEtag() != null && entityFromServer.getEtag().equals(existingEntity.getEtag())) {
+                                if (etagsEnabled && 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;
                                 }
@@ -80,7 +83,6 @@ 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()){
@@ -90,7 +92,8 @@ public class SyncHelper {
                         return;
                     }
                 }
-                provider.onError(throwable, responseCallback);
+                super.onError(throwable);
+                provider.onError(responseCallback);
                 responseCallback.onError(throwable);
             }
         }, lastSync);
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 11fb38a66..8e8104692 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
@@ -129,12 +129,10 @@ public abstract class AbstractSyncDataProvider<T extends IRemoteEntity> {
         //do nothing
     }
 
-    public void onError(Throwable error, IResponseCallback<Boolean> responseCallback) {
+    public void onError(IResponseCallback<Boolean> responseCallback) {
         if (parent != null) {
             parent.childDone(this, responseCallback, false);
         }
-        //TODO: what to do? what side effect would the following have:
-//        responseCallback.onError(error);
     }
 
     public T applyUpdatesFromRemote(T localEntity, T remoteEntity, Long accountId) {
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 6dde6b45c..6f908af1a 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
@@ -65,7 +65,7 @@ public class AccessControlDataProvider extends AbstractSyncDataProvider<AccessCo
                 serverAdapter.getSingleUserData(uid, new IResponseCallback<OcsUser>(account) {
                     @Override
                     public void onResponse(OcsUser response) {
-                        DeckLog.log(response.toString());
+                        DeckLog.log(response);
                         User user = new User();
                         user.setUid(response.getId());
                         user.setPrimaryKey(response.getId());
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 781f7b1f4..9442085cb 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
@@ -1,5 +1,6 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import android.annotation.SuppressLint;
 import android.net.Uri;
 
 import java.io.File;
@@ -67,7 +68,7 @@ public class AttachmentDataProvider extends AbstractSyncDataProvider<Attachment>
     @Override
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<Attachment> responder, Attachment entity) {
         File file = new File(entity.getLocalPath());
-        serverAdapter.uploadAttachment(board.getId(), stack.getId(), card.getId(), entity.getType(), file, new IResponseCallback<Attachment>(responder.getAccount()) {
+        serverAdapter.uploadAttachment(board.getId(), stack.getId(), card.getId(), file, new IResponseCallback<Attachment>(responder.getAccount()) {
             @Override
             public void onResponse(Attachment response) {
                 if (file.delete()) {
@@ -77,10 +78,11 @@ public class AttachmentDataProvider extends AbstractSyncDataProvider<Attachment>
                 }
             }
 
+            @SuppressLint("MissingSuperCall")
             @Override
             public void onError(Throwable throwable) {
                 if (!file.delete()) {
-                    DeckLog.error("Could not delete local file: " + file.getAbsolutePath());
+                    DeckLog.error("Could not delete local file:", file.getAbsolutePath());
                 }
                 // if (HandledServerErrors.ATTACHMENTS_FILE_ALREADY_EXISTS == HandledServerErrors.fromThrowable(throwable)) {
                 dataBaseAdapter.deleteAttachment(accountId, entity, false);
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 0ceac2cd8..ddb34937f 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
@@ -2,6 +2,8 @@ package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
 import android.annotation.SuppressLint;
 
+import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
+
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -22,7 +24,6 @@ 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.model.ocs.Version;
 import it.niedermann.nextcloud.deck.model.propagation.CardUpdate;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.ServerAdapter;
 import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.DataBaseAdapter;
@@ -30,6 +31,7 @@ import it.niedermann.nextcloud.deck.persistence.sync.helpers.SyncHelper;
 
 public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
 
+    private static final String ALREADY_ARCHIVED_INDICATOR = "Operation not allowed. This card is archived.";
     protected Board board;
     protected FullStack stack;
 
@@ -42,11 +44,12 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     @Override
     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()) {
-            responder.onResponse(result);
+            responder.onResponse(new ArrayList<>());
             return;
         }
+        List<FullCard> result = Collections.synchronizedList(new ArrayList<>());
         for (Card card : stack.getCards()) {
             serverAdapter.getCard(board.getId(), stack.getId(), card.getId(), new IResponseCallback<FullCard>(responder.getAccount()) {
                 @Override
@@ -142,7 +145,7 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
         }
         syncHelper.doSyncFor(new AttachmentDataProvider(this, board, stack.getStack(), existingEntity, attachments));
 
-        if (callback.getAccount().getServerDeckVersionAsObject().isGreaterOrEqualTo(new Version("1.0.0", 1, 0, 0))) {
+        if (callback.getAccount().getServerDeckVersionAsObject().supportsComments()) {
             DeckLog.verbose("Comments - Version is OK, SYNC");
             syncHelper.doSyncFor(new DeckCommentsDataProvider(this, existingEntity.getCard()));
         } else {
@@ -167,7 +170,27 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
     public void updateOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<FullCard> callback, FullCard entity) {
         CardUpdate update = toCardUpdate(entity);
         update.setStackId(stack.getId());
-        serverAdapter.updateCard(board.getId(), stack.getId(), update, callback);
+        // https://github.com/stefan-niedermann/nextcloud-deck/issues/787 resolve archiving-conflict
+        serverAdapter.updateCard(board.getId(), stack.getId(), update, new IResponseCallback<FullCard>(callback.getAccount()) {
+            @Override
+            public void onResponse(FullCard response) {
+                callback.onResponse(response);
+            }
+
+            @SuppressLint("MissingSuperCall")
+            @Override
+            public void onError(Throwable throwable) {
+                if (throwable.getClass() == NextcloudHttpRequestFailedException.class &&
+                        throwable.getCause() != null &&
+                        throwable.getCause().getClass() == IllegalStateException.class &&
+                        throwable.getCause().getMessage() != null &&
+                        throwable.getCause().getMessage().contains(ALREADY_ARCHIVED_INDICATOR)) {
+                    callback.onResponse(entity);
+                } else {
+                    callback.onError(throwable);
+                }
+            }
+        });
     }
 
     @Override
@@ -205,6 +228,10 @@ public class CardDataProvider extends AbstractSyncDataProvider<FullCard> {
         Account account = callback.getAccount();
         for (JoinCardWithLabel changedLabelLocal : changedLabels) {
             Card card = dataBaseAdapter.getCardByLocalIdDirectly(account.getId(), changedLabelLocal.getCardId());
+            if (card == null) {
+                // https://github.com/stefan-niedermann/nextcloud-deck/issues/683#issuecomment-759116820
+                continue;
+            }
             if (this.stack == null) {
                 stack = dataBaseAdapter.getFullStackByLocalIdDirectly(card.getStackId());
             } else {
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardPropagationDataProvider.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardPropagationDataProvider.java
index 422a11caa..aa5da8558 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardPropagationDataProvider.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/sync/helpers/providers/CardPropagationDataProvider.java
@@ -1,8 +1,11 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import android.annotation.SuppressLint;
+
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.model.Board;
 import it.niedermann.nextcloud.deck.model.Card;
+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.propagation.CardUpdate;
@@ -17,9 +20,42 @@ public class CardPropagationDataProvider extends CardDataProvider {
 
     @Override
     public void createOnServer(ServerAdapter serverAdapter, DataBaseAdapter dataBaseAdapter, long accountId, IResponseCallback<FullCard> responder, FullCard entity) {
-        Card card = entity.getCard();
-        card.setStackId(stack.getId());
-        serverAdapter.createCard(board.getId(), stack.getId(), card, responder);
+        // make sure, all ancestors are synced properly
+        if (board.getId() == null) {
+            serverAdapter.createBoard(board, new IResponseCallback<FullBoard>(responder.getAccount()) {
+                @Override
+                public void onResponse(FullBoard response) {
+                    board.setId(response.getId());
+                    board.setEtag(response.getEtag());
+                    createOnServer(serverAdapter, dataBaseAdapter, accountId, responder, entity);
+                }
+
+                @SuppressLint("MissingSuperCall")
+                @Override
+                public void onError(Throwable throwable) {
+                    responder.onError(throwable);
+                }
+            });
+        } else  if (stack.getId() == null) {
+            serverAdapter.createStack(board, stack.getStack(), new IResponseCallback<FullStack>(responder.getAccount()) {
+                @Override
+                public void onResponse(FullStack response) {
+                    stack.setId(response.getId());
+                    stack.setEtag(response.getEtag());
+                    createOnServer(serverAdapter, dataBaseAdapter, accountId, responder, entity);
+                }
+
+                @SuppressLint("MissingSuperCall")
+                @Override
+                public void onError(Throwable throwable) {
+                    responder.onError(throwable);
+                }
+            });
+        } else {
+            Card card = entity.getCard();
+            card.setStackId(stack.getId());
+            serverAdapter.createCard(board.getId(), stack.getId(), card, responder);
+        }
     }
 
 
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 caa7c68e6..62354d1cf 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
@@ -1,5 +1,7 @@
 package it.niedermann.nextcloud.deck.persistence.sync.helpers.providers;
 
+import android.annotation.SuppressLint;
+
 import java.time.Instant;
 import java.util.List;
 
@@ -61,10 +63,11 @@ public class LabelDataProvider extends AbstractSyncDataProvider<Label> {
                 responder.onResponse(response);
             }
 
+            @SuppressLint("MissingSuperCall")
             @Override
             public void onError(Throwable throwable) {
                 if (HandledServerErrors.LABELS_TITLE_MUST_BE_UNIQUE == HandledServerErrors.fromThrowable(throwable)) {
-                    DeckLog.log(throwable.getCause().getMessage() + ": " + entitiy.toString());
+                    DeckLog.log(throwable.getCause().getMessage() + ":", entitiy);
                     dataBaseAdapter.deleteLabelPhysically(entitiy);
                     responder.onResponse(entitiy);
                 } else {
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
index b9bfb8b31..5379be6d9 100644
--- 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
@@ -33,6 +33,7 @@ public class OcsProjectDataProvider extends AbstractSyncDataProvider<OcsProject>
             public void onError(Throwable throwable) {
                 super.onError(throwable);
                 // dont break the sync!
+                // TODO i got here HTTP 404 once, maybe this should be considered?
                 DeckLog.logError(throwable);
                 responder.onResponse(Collections.emptyList());
             }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/util/RealPathUtils.java b/app/src/main/java/it/niedermann/nextcloud/deck/persistence/util/RealPathUtils.java
deleted file mode 100644
index f45226ebd..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/persistence/util/RealPathUtils.java
+++ /dev/null
@@ -1,94 +0,0 @@
-package it.niedermann.nextcloud.deck.persistence.util;
-
-import android.annotation.SuppressLint;
-import android.content.Context;
-import android.database.Cursor;
-import android.net.Uri;
-import android.os.Build;
-import android.provider.DocumentsContract;
-import android.provider.MediaStore;
-
-import androidx.loader.content.CursorLoader;
-
-import java.io.File;
-
-import it.niedermann.nextcloud.deck.DeckLog;
-
-public class RealPathUtils {
-
-    public static File getRealPath(Context context, Uri uri){
-        String path = null;
-        if (Build.VERSION.SDK_INT < 11)
-            path = RealPathUtils.getRealPathFromURI_BelowAPI11(context, uri);
-
-            // SDK >= 11 && SDK < 19
-        else if (Build.VERSION.SDK_INT < 19)
-            path = RealPathUtils.getRealPathFromURI_API11to18(context, uri);
-
-            // SDK > 19 (Android 4.4)
-        else
-            path = RealPathUtils.getRealPathFromURI_API19(context, uri);
-        DeckLog.log("File Path: " + path);
-        // Get the file instance
-        return new File(path);
-    }
-
-@SuppressLint("NewApi")
-public static String getRealPathFromURI_API19(Context context, Uri uri){
-    String filePath = "";
-    String wholeID = DocumentsContract.getDocumentId(uri);
-
-    // Split at colon, use second item in the array
-    String id;
-    if (wholeID.contains(":")){
-        id = wholeID.split(":")[1];
-    } else {
-        id = wholeID;
-    }
-
-    String[] column = { MediaStore.Images.Media.DATA };
-
-    // where id is equal to
-    String sel = MediaStore.Images.Media._ID + "=?";
-
-    Cursor cursor = context.getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
-            column, sel, new String[]{ id }, null);
-
-    int columnIndex = cursor.getColumnIndex(column[0]);
-
-    if (cursor.moveToFirst()) {
-        filePath = cursor.getString(columnIndex);
-    }
-    cursor.close();
-    return filePath;
-}
-
-
-@SuppressLint("NewApi")
-public static String getRealPathFromURI_API11to18(Context context, Uri contentUri) {
-    String[] proj = { MediaStore.Images.Media.DATA };
-    String result = null;
-
-    CursorLoader cursorLoader = new CursorLoader(
-            context,
-            contentUri, proj, null, null, null);
-    Cursor cursor = cursorLoader.loadInBackground();
-
-    if(cursor != null){
-        int column_index =
-                cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
-        cursor.moveToFirst();
-        result = cursor.getString(column_index);
-    }
-    return result;
-}
-
-public static String getRealPathFromURI_BelowAPI11(Context context, Uri contentUri){
-    String[] proj = { MediaStore.Images.Media.DATA };
-    Cursor cursor = context.getContentResolver().query(contentUri, proj, null, null, null);
-    int column_index
-            = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
-    cursor.moveToFirst();
-    return cursor.getString(column_index);
-}
-}
\ No newline at end of file
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 3ded31bb7..bcf5340d8 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
@@ -1,20 +1,17 @@
 package it.niedermann.nextcloud.deck.ui;
 
 import android.annotation.SuppressLint;
+import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.database.sqlite.SQLiteConstraintException;
-import android.graphics.drawable.Drawable;
 import android.net.Uri;
-import android.os.Build;
 import android.os.Bundle;
 import android.view.View;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.StringRes;
 import androidx.appcompat.app.AppCompatActivity;
-import androidx.core.content.ContextCompat;
-import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.preference.PreferenceManager;
 
 import com.nextcloud.android.sso.AccountImporter;
@@ -89,12 +86,6 @@ public class ImportAccountActivity extends AppCompatActivity {
                 AccountImporter.requestAndroidAccountPermissionsAndPickAccount(this);
             }
         });
-
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
-            Drawable wrapDrawable = DrawableCompat.wrap(binding.progressCircular.getIndeterminateDrawable());
-            DrawableCompat.setTint(wrapDrawable, ContextCompat.getColor(this, R.color.defaultBrand));
-            binding.progressCircular.setIndeterminateDrawable(DrawableCompat.unwrap(wrapDrawable));
-        }
     }
 
     @Override
@@ -137,7 +128,7 @@ public class ImportAccountActivity extends AppCompatActivity {
                             } else {
                                 // Remember last account - THIS HAS TO BE DONE SYNCHRONOUSLY
                                 SharedPreferences.Editor editor = sharedPreferences.edit();
-                                DeckLog.log("--- Write: shared_preference_last_account" + " | " + createdAccount.getId());
+                                DeckLog.log("--- Write: shared_preference_last_account | ", createdAccount.getId());
                                 editor.putLong(sharedPreferenceLastAccount, createdAccount.getId());
                                 editor.commit();
 
@@ -145,7 +136,7 @@ public class ImportAccountActivity extends AppCompatActivity {
                                     @Override
                                     public void onResponse(Capabilities response) {
                                         if (!response.isMaintenanceEnabled()) {
-                                            if (response.getDeckVersion().isSupported(getApplicationContext())) {
+                                            if (response.getDeckVersion().isSupported()) {
                                                 syncManager.synchronize(new IResponseCallback<Boolean>(account) {
                                                     @Override
                                                     public void onResponse(Boolean response) {
@@ -216,7 +207,7 @@ public class ImportAccountActivity extends AppCompatActivity {
         DeckLog.log("Rolling back account creation for " + accountId);
         syncManager.deleteAccount(accountId);
         SharedPreferences.Editor editor = sharedPreferences.edit();
-        DeckLog.log("--- Remove: shared_preference_last_account" + " | " + accountId);
+        DeckLog.log("--- Remove: shared_preference_last_account |", accountId);
         editor.remove(sharedPreferenceLastAccount);
         editor.commit(); // Has to be done synchronously
         runOnUiThread(() -> binding.addButton.setEnabled(true));
@@ -251,4 +242,8 @@ public class ImportAccountActivity extends AppCompatActivity {
         editor.putBoolean(prefKeyWifiOnly, originalWifiOnlyValue);
         editor.apply();
     }
+
+    public static Intent createIntent(@NonNull Context context) {
+        return new Intent(context, ImportAccountActivity.class);
+    }
 }
\ No newline at end of file
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 d7e726a7d..58f08237e 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
@@ -11,9 +11,7 @@ import android.net.Network;
 import android.net.NetworkInfo;
 import android.net.NetworkRequest;
 import android.net.Uri;
-import android.os.Build;
 import android.os.Bundle;
-import android.preference.PreferenceManager;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -22,10 +20,10 @@ import android.widget.PopupMenu;
 import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.annotation.RequiresApi;
 import androidx.annotation.UiThread;
 import androidx.appcompat.app.ActionBarDrawerToggle;
 import androidx.appcompat.app.AppCompatDelegate;
+import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
 import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.core.util.Pair;
@@ -34,6 +32,7 @@ import androidx.core.view.ViewCompat;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.Observer;
 import androidx.lifecycle.ViewModelProvider;
+import androidx.preference.PreferenceManager;
 import androidx.viewpager2.widget.ViewPager2;
 
 import com.bumptech.glide.Glide;
@@ -58,6 +57,7 @@ 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;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.databinding.ActivityMainBinding;
 import it.niedermann.nextcloud.deck.databinding.NavHeaderMainBinding;
 import it.niedermann.nextcloud.deck.exceptions.OfflineException;
@@ -107,7 +107,7 @@ import static it.niedermann.nextcloud.deck.DeckApplication.NO_STACK_ID;
 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.saveCurrentAccount;
 import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentBoardId;
 import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentStackId;
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
@@ -132,9 +132,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
     private FilterViewModel filterViewModel;
     private PickStackViewModel pickStackViewModel;
 
-    protected static final int ACTIVITY_ABOUT = 1;
     protected static final int ACTIVITY_SETTINGS = 2;
-    public static final int ACTIVITY_MANAGE_ACCOUNTS = 4;
 
     @NonNull
     protected List<Account> accountsList = new ArrayList<>();
@@ -158,8 +156,6 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
     private boolean firstAccountAdded = false;
     private ConnectivityManager.NetworkCallback networkCallback;
 
-    private String accountAlreadyAdded;
-    private String urlFragmentUpdateDeck;
     private String addList;
     private String addBoard;
     @Nullable
@@ -186,8 +182,6 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
         addList = getString(R.string.add_list);
         addBoard = getString(R.string.add_board);
-        accountAlreadyAdded = getString(R.string.account_already_added);
-        urlFragmentUpdateDeck = getString(R.string.url_fragment_update_deck);
 
         setSupportActionBar(binding.toolbar);
 
@@ -198,11 +192,26 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
         binding.navigationView.setNavigationItemSelectedListener(this);
         sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
 
+        DeckApplication.readCurrentAccountColor().observe(this, (accountColor) -> {
+            headerBinding.headerView.setBackgroundColor(accountColor);
+            @ColorInt final int headerTextColor = contrastRatioIsSufficientBigAreas(accountColor, Color.WHITE) ? Color.WHITE : Color.BLACK;
+            DrawableCompat.setTint(headerBinding.logo.getDrawable(), headerTextColor);
+            DrawableCompat.setTint(headerBinding.copyDebugLogs.getDrawable(), headerTextColor);
+        });
+
+        mainViewModel.isDebugModeEnabled().observe(this, (enabled) -> headerBinding.copyDebugLogs.setVisibility(enabled ? View.VISIBLE : View.GONE));
+        headerBinding.copyDebugLogs.setOnClickListener((v) -> {
+            try {
+                DeckLog.shareLogAsFile(this);
+            } catch (Exception e) {
+                ExceptionDialogFragment.newInstance(e, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
         switchMap(mainViewModel.hasAccounts(), hasAccounts -> {
             if (hasAccounts) {
                 return mainViewModel.readAccounts();
             } else {
-                startActivityForResult(new Intent(this, ImportAccountActivity.class), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
+                startActivityForResult(ImportAccountActivity.createIntent(this), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
                 return null;
             }
         }).observe(this, (List<Account> accounts) -> {
@@ -221,21 +230,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                     mainViewModel.setCurrentAccount(account);
                     if (!firstAccountAdded) {
                         DeckLog.info("Syncing the current account on app start");
-                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
-                            registerAutoSyncOnNetworkAvailable();
-                        } else {
-                            mainViewModel.synchronize(new IResponseCallback<Boolean>(mainViewModel.getCurrentAccount()) {
-                                @Override
-                                public void onResponse(Boolean response) {
-                                }
-
-                                @Override
-                                public void onError(Throwable throwable) {
-                                    super.onError(throwable);
-                                    showSyncFailedSnackbar(throwable);
-                                }
-                            });
-                        }
+                        registerAutoSyncOnNetworkAvailable();
                         firstAccountAdded = false;
                     }
                     break;
@@ -246,7 +241,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                 SingleAccountHelper.setCurrentAccount(getApplicationContext(), mainViewModel.getCurrentAccount().getName());
                 mainViewModel.recreateSyncManager();
 
-                saveCurrentAccountId(this, mainViewModel.getCurrentAccount().getId());
+                saveCurrentAccount(this, mainViewModel.getCurrentAccount());
                 if (mainViewModel.getCurrentAccount().isMaintenanceEnabled()) {
                     refreshCapabilities(mainViewModel.getCurrentAccount());
                 }
@@ -264,18 +259,21 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                     }
 
                     boardsList = boards;
+                    Board currentBoard = null;
 
                     if (boardsList.size() > 0) {
                         boolean currentBoardIdWasInList = false;
                         for (int i = 0; i < boardsList.size(); i++) {
                             if (lastBoardId == boardsList.get(i).getLocalId() || lastBoardId == NO_BOARD_ID) {
-                                setCurrentBoard(boardsList.get(i));
+                                currentBoard = boardsList.get(i);
+                                setCurrentBoard(currentBoard);
                                 currentBoardIdWasInList = true;
                                 break;
                             }
                         }
                         if (!currentBoardIdWasInList) {
-                            setCurrentBoard(boardsList.get(0));
+                            currentBoard = boardsList.get(0);
+                            setCurrentBoard(currentBoard);
                         }
 
                         binding.filter.setOnClickListener((v) -> FilterDialogFragment.newInstance().show(getSupportFragmentManager(), EditStackDialogFragment.class.getCanonicalName()));
@@ -286,13 +284,14 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                         binding.filter.setOnClickListener(null);
                     }
 
+                    final Board finalCurrentBoard = currentBoard;
                     if (hasArchivedBoardsLiveData != null && hasArchivedBoardsLiveDataObserver != null) {
                         hasArchivedBoardsLiveData.removeObserver(hasArchivedBoardsLiveDataObserver);
                     }
                     hasArchivedBoardsLiveData = mainViewModel.hasArchivedBoards(currentAccount.getId());
                     hasArchivedBoardsLiveDataObserver = (hasArchivedBoards) -> {
                         mainViewModel.setCurrentAccountHasArchivedBoards(Boolean.TRUE.equals(hasArchivedBoards));
-                        inflateBoardMenu();
+                        inflateBoardMenu(finalCurrentBoard);
                     };
                     hasArchivedBoardsLiveData.observe(this, hasArchivedBoardsLiveDataObserver);
                 };
@@ -300,21 +299,21 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
                 Glide
                         .with(binding.accountSwitcher.getContext())
-                        .load(currentAccount.getAvatarUrl(64))
+                        .load(currentAccount.getAvatarUrl(binding.accountSwitcher.getWidth()))
                         .placeholder(R.drawable.ic_baseline_account_circle_24)
                         .error(R.drawable.ic_baseline_account_circle_24)
                         .apply(RequestOptions.circleCropTransform())
                         .into(binding.accountSwitcher);
 
-                DeckLog.verbose("Displaying maintenance mode info for " + mainViewModel.getCurrentAccount().getName() + ": " + mainViewModel.getCurrentAccount().isMaintenanceEnabled());
+                DeckLog.verbose("Displaying maintenance mode info for", mainViewModel.getCurrentAccount().getName() + ":" + mainViewModel.getCurrentAccount().isMaintenanceEnabled());
                 binding.infoBox.setVisibility(mainViewModel.getCurrentAccount().isMaintenanceEnabled() ? View.VISIBLE : View.GONE);
                 if (mainViewModel.isCurrentAccountIsSupportedVersion()) {
                     binding.infoBoxVersionNotSupported.setVisibility(View.GONE);
                 } else {
-                    binding.infoBoxVersionNotSupportedText.setText(getString(R.string.info_box_version_not_supported, mainViewModel.getCurrentAccount().getServerDeckVersion(), Version.minimumSupported(this).getOriginalVersion()));
+                    binding.infoBoxVersionNotSupportedText.setText(getString(R.string.info_box_version_not_supported, mainViewModel.getCurrentAccount().getServerDeckVersion(), Version.minimumSupported().getOriginalVersion()));
                     binding.infoBoxVersionNotSupportedText.setOnClickListener((v) -> {
                         Intent openURL = new Intent(Intent.ACTION_VIEW);
-                        openURL.setData(Uri.parse(mainViewModel.getCurrentAccount().getUrl() + urlFragmentUpdateDeck));
+                        openURL.setData(Uri.parse(mainViewModel.getCurrentAccount().getUrl() + getString(R.string.url_fragment_update_deck)));
                         startActivity(openURL);
                     });
                     binding.infoBoxVersionNotSupported.setVisibility(View.VISIBLE);
@@ -329,7 +328,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
             dragAndDrop.register(binding.viewPager, binding.stackTitles, getSupportFragmentManager());
             dragAndDrop.addItemMovedByDragListener((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);
+                DeckLog.info("Card", movedCard.getCard().getTitle(), "was moved to Stack", stackId, "on position", position);
             });
 
 
@@ -429,10 +428,6 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
         applyBrandToFAB(mainColor, binding.fab);
         // TODO We assume, that the background of the spinner is always white
         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);
-        headerBinding.appName.setTextColor(headerTextColor);
         DrawableCompat.setTint(binding.filterIndicator.getDrawable(), getSecondaryForegroundColorDependingOnTheme(this, mainColor));
     }
 
@@ -446,27 +441,35 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
     @Override
     public void onCreateStack(String stackName) {
-        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)
+        DeckLog.info("Create Stack in account", mainViewModel.getCurrentAccount().getName(), "on board", mainViewModel.getCurrentBoardLocalId());
+        mainViewModel.createStack(mainViewModel.getCurrentAccount().getId(), stackName, mainViewModel.getCurrentBoardLocalId(), new ResponseCallback<FullStack>() {
+            @Override
+            public void onResponse(FullStack response) {
+                runOnUiThread(() -> binding.viewPager.setCurrentItem(stackAdapter.getItemCount()));
+            }
+
+            @Override
+            public void onError(Throwable error) {
+                ResponseCallback.super.onError(error);
+                runOnUiThread(() -> 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());
+                        .show());
             }
         });
     }
 
     @Override
     public void onUpdateStack(long localStackId, String stackName) {
-        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());
+        mainViewModel.updateStackTitle(localStackId, stackName, new ResponseCallback<FullStack>() {
+            @Override
+            public void onResponse(FullStack response) {
+                DeckLog.info("Successfully updated", Stack.class.getSimpleName(), "to", stackName);
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                ResponseCallback.super.onError(throwable);
+                runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
             }
         });
     }
@@ -481,30 +484,42 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
         boardToCreate.setPermissionEdit(true);
         boardToCreate.setPermissionManage(true);
 
-        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();
+        mainViewModel.createBoard(mainViewModel.getCurrentAccount().getId(), boardToCreate, new ResponseCallback<FullBoard>() {
+            @Override
+            public void onResponse(FullBoard response) {
+                runOnUiThread(() -> {
+                    if (response != null) {
+                        boardsList.add(response.getBoard());
+                        setCurrentBoard(response.getBoard());
+                        inflateBoardMenu(response.getBoard());
+                        EditStackDialogFragment.newInstance(NO_STACK_ID).show(getSupportFragmentManager(), addList);
+                    }
+                    boardsLiveData.observe(MainActivity.this, boardsLiveDataObserver);
+                });
             }
-            if (createdBoard != null && !createLiveData.hasError()) {
-                boardsList.add(createdBoard.getBoard());
-                setCurrentBoard(createdBoard.getBoard());
 
-                inflateBoardMenu();
-                EditStackDialogFragment.newInstance(NO_STACK_ID).show(getSupportFragmentManager(), addList);
+            @Override
+            public void onError(Throwable throwable) {
+                ResponseCallback.super.onError(throwable);
+                runOnUiThread(() -> BrandedSnackbar.make(binding.coordinatorLayout, R.string.synchronization_failed, Snackbar.LENGTH_LONG)
+                        .setAction(R.string.simple_more, v -> ExceptionDialogFragment.newInstance(throwable, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()))
+                        .show());
             }
-            boardsLiveData.observe(this, boardsLiveDataObserver);
         });
     }
 
     @Override
     public void onUpdateBoard(FullBoard 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());
+        mainViewModel.updateBoard(fullBoard, new ResponseCallback<FullBoard>() {
+            @Override
+            public void onResponse(FullBoard response) {
+                DeckLog.info("Successfully updated board", fullBoard.getBoard().getTitle());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                ResponseCallback.super.onError(throwable);
+                runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
             }
         });
     }
@@ -517,18 +532,20 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                     binding.swipeRefreshLayout.setRefreshing(false);
                 } else {
                     // If we notice after updating the capabilities, that the new version is not supported, but it was previously, recreate the activity to make sure all elements are disabled properly
-                    if (mainViewModel.getCurrentAccount().getServerDeckVersionAsObject().isSupported(MainActivity.this) && !response.getDeckVersion().isSupported(MainActivity.this)) {
-                        recreate();
+                    if (mainViewModel.getCurrentAccount().getServerDeckVersionAsObject().isSupported() && !response.getDeckVersion().isSupported()) {
+                        ActivityCompat.recreate(MainActivity.this);
                     }
                 }
             }
 
             @Override
             public void onError(Throwable throwable) {
+                binding.swipeRefreshLayout.setRefreshing(false);
                 if (throwable instanceof OfflineException) {
                     DeckLog.info("Cannot refresh capabilities because device is offline.");
                 } else {
                     super.onError(throwable);
+                    ExceptionDialogFragment.newInstance(throwable, account).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
                 }
             }
         });
@@ -552,6 +569,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
         lastBoardId = board.getLocalId();
         saveCurrentBoardId(this, mainViewModel.getCurrentAccount().getId(), mainViewModel.getCurrentBoardLocalId());
+        binding.navigationView.setCheckedItem(boardsList.indexOf(board));
 
         binding.toolbar.setTitle(board.getTitle());
 
@@ -637,21 +655,22 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
     }
 
     @UiThread
-    protected void inflateBoardMenu() {
+    protected void inflateBoardMenu(@Nullable Board currentBoard) {
         binding.navigationView.setItemIconTintList(null);
         Menu menu = binding.navigationView.getMenu();
         menu.clear();
-        DrawerMenuUtil.inflateBoards(this, menu, this.boardsList, mainViewModel.currentAccountHasArchivedBoards(), mainViewModel.getCurrentAccount().getServerDeckVersionAsObject().isSupported(this));
+        DrawerMenuUtil.inflateBoards(this, menu, this.boardsList, mainViewModel.currentAccountHasArchivedBoards(), mainViewModel.getCurrentAccount().getServerDeckVersionAsObject().isSupported());
+        binding.navigationView.setCheckedItem(boardsList.indexOf(currentBoard));
     }
 
     @Override
     public boolean onNavigationItemSelected(@NonNull MenuItem item) {
         switch (item.getItemId()) {
             case MENU_ID_ABOUT:
-                startActivityForResult(AboutActivity.createIntent(this, mainViewModel.getCurrentAccount()), MainActivity.ACTIVITY_ABOUT);
+                startActivity(AboutActivity.createIntent(this, mainViewModel.getCurrentAccount()));
                 break;
             case MENU_ID_SETTINGS:
-                startActivityForResult(new Intent(this, SettingsActivity.class), MainActivity.ACTIVITY_SETTINGS);
+                startActivityForResult(SettingsActivity.createIntent(this), MainActivity.ACTIVITY_SETTINGS);
                 break;
             case MENU_ID_ADD_BOARD:
                 EditBoardDialogFragment.newInstance().show(getSupportFragmentManager(), addBoard);
@@ -681,10 +700,18 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                                 : 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());
+                            mainViewModel.archiveCardsInStack(mainViewModel.getCurrentAccount().getId(), stackLocalId, filterInformation == null ? new FilterInformation() : filterInformation, new ResponseCallback<Void>() {
+                                @Override
+                                public void onResponse(Void response) {
+                                    DeckLog.info("Successfully archived all cards in stack local id", stackLocalId);
+                                }
+
+                                @Override
+                                public void onError(Throwable throwable) {
+                                    if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                                        ResponseCallback.super.onError(throwable);
+                                        runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
+                                    }
                                 }
                             });
                         })
@@ -761,7 +788,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
         switch (requestCode) {
             case MainActivity.ACTIVITY_SETTINGS:
                 if (resultCode == RESULT_OK) {
-                    recreate();
+                    ActivityCompat.recreate(this);
                 }
                 break;
             case ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT:
@@ -787,17 +814,19 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                                     @Override
                                     public void onResponse(Capabilities response) {
                                         if (!response.isMaintenanceEnabled()) {
-                                            if (response.getDeckVersion().isSupported(getApplicationContext())) {
+                                            if (response.getDeckVersion().isSupported()) {
                                                 runOnUiThread(() -> {
                                                     mainViewModel.setSyncManager(importSyncManager);
-                                                    mainViewModel.setCurrentAccount(account);
 
                                                     final Snackbar importSnackbar = BrandedSnackbar.make(binding.coordinatorLayout, R.string.account_is_getting_imported, Snackbar.LENGTH_INDEFINITE);
                                                     importSnackbar.show();
-                                                    importSyncManager.synchronize(new IResponseCallback<Boolean>(mainViewModel.getCurrentAccount()) {
+                                                    importSyncManager.synchronize(new IResponseCallback<Boolean>(createdAccount) {
                                                         @Override
                                                         public void onResponse(Boolean response) {
                                                             importSnackbar.dismiss();
+                                                            runOnUiThread(() -> BrandedSnackbar.make(binding.coordinatorLayout, getString(R.string.account_imported), Snackbar.LENGTH_LONG)
+                                                                    .setAction(R.string.simple_switch, (a) -> mainViewModel.setCurrentAccount(createdAccount))
+                                                                    .show());
                                                         }
 
                                                         @Override
@@ -811,14 +840,14 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                                                     });
                                                 });
                                             } else {
-                                                DeckLog.warn("Cannot import account because server version is too low (" + response.getDeckVersion() + "). Minimum server version is currently " + Version.minimumSupported(getApplicationContext()));
+                                                DeckLog.warn("Cannot import account because server version is too low (" + response.getDeckVersion() + "). Minimum server version is currently", Version.minimumSupported());
                                                 runOnUiThread(() -> new BrandedAlertDialogBuilder(MainActivity.this)
                                                         .setTitle(R.string.update_deck)
                                                         .setMessage(getString(R.string.deck_outdated_please_update, response.getDeckVersion().getOriginalVersion()))
                                                         .setNegativeButton(R.string.simple_discard, null)
                                                         .setPositiveButton(R.string.simple_update, (dialog, whichButton) -> {
                                                             final Intent openURL = new Intent(Intent.ACTION_VIEW);
-                                                            openURL.setData(Uri.parse(createdAccount.getUrl() + urlFragmentUpdateDeck));
+                                                            openURL.setData(Uri.parse(createdAccount.getUrl() + getString(R.string.url_fragment_update_deck)));
                                                             startActivity(openURL);
                                                             finish();
                                                         }).show());
@@ -855,7 +884,7 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                                 final Throwable error = accountLiveData.getError();
                                 if (error instanceof SQLiteConstraintException) {
                                     DeckLog.warn("Account already added");
-                                    BrandedSnackbar.make(binding.coordinatorLayout, accountAlreadyAdded, Snackbar.LENGTH_LONG).show();
+                                    BrandedSnackbar.make(binding.coordinatorLayout, R.string.account_already_added, Snackbar.LENGTH_LONG).show();
                                 } else {
                                     ExceptionDialogFragment.newInstance(error, createdAccount).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
                                 }
@@ -877,7 +906,6 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
         }
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
     private void registerAutoSyncOnNetworkAvailable() {
         final ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
         NetworkRequest.Builder builder = new NetworkRequest.Builder();
@@ -919,10 +947,18 @@ 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 = mainViewModel.deleteStack(mainViewModel.getCurrentAccount().getId(), stackId, mainViewModel.getCurrentBoardLocalId());
-        observeOnce(deleteStackLiveData, this, (v) -> {
-            if (deleteStackLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteStackLiveData.getError())) {
-                ExceptionDialogFragment.newInstance(deleteStackLiveData.getError(), mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+        mainViewModel.deleteStack(mainViewModel.getCurrentAccount().getId(), stackId, mainViewModel.getCurrentBoardLocalId(), new ResponseCallback<Void>() {
+            @Override
+            public void onResponse(Void response) {
+                DeckLog.info("Successfully deleted stack with local id", stackLocalId, "and remote id", stackId);
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                    ResponseCallback.super.onError(throwable);
+                    runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
+                }
             }
         });
     }
@@ -942,10 +978,18 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
             }
         }
 
-        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());
+        mainViewModel.deleteBoard(board, new ResponseCallback<Void>() {
+            @Override
+            public void onResponse(Void response) {
+                DeckLog.info("Successfully deleted board", board.getTitle());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                    ResponseCallback.super.onError(throwable);
+                    runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
+                }
             }
         });
 
@@ -968,10 +1012,16 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
 
     @Override
     public void onArchive(@NonNull Board 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());
+        mainViewModel.archiveBoard(board, new ResponseCallback<FullBoard>() {
+            @Override
+            public void onResponse(FullBoard response) {
+                DeckLog.info("Successfully archived board", board.getTitle());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                ResponseCallback.super.onError(throwable);
+                runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
             }
         });
     }
@@ -987,18 +1037,27 @@ public class MainActivity extends BrandedActivity implements DeleteStackListener
                     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();
+                    mainViewModel.cloneBoard(board.getAccountId(), board.getLocalId(), board.getAccountId(), board.getColor(), checkedItems[0], new ResponseCallback<FullBoard>() {
+                        @Override
+                        public void onResponse(FullBoard response) {
+                            runOnUiThread(() -> {
+                                snackbar.dismiss();
+                                setCurrentBoard(response.getBoard());
+                                BrandedSnackbar.make(binding.coordinatorLayout, getString(R.string.successfully_cloned_board, response.getBoard().getTitle()), Snackbar.LENGTH_LONG)
+                                        .setAction(R.string.edit, v -> EditBoardDialogFragment.newInstance(response.getLocalId()).show(getSupportFragmentManager(), EditBoardDialogFragment.class.getSimpleName()))
+                                        .show();
+                            });
                         }
-                    }));
+
+                        @Override
+                        public void onError(Throwable throwable) {
+                            ResponseCallback.super.onError(throwable);
+                            runOnUiThread(() -> {
+                                snackbar.dismiss();
+                                ExceptionDialogFragment.newInstance(throwable, mainViewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                            });
+                        }
+                    });
                 })
                 .setNeutralButton(android.R.string.cancel, null)
                 .show();
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 ac244b88e..53443d07c 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
@@ -9,11 +9,15 @@ import androidx.core.util.Pair;
 import androidx.lifecycle.AndroidViewModel;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
+import androidx.preference.PreferenceManager;
 
 import java.io.File;
 import java.util.List;
 
+import it.niedermann.android.sharedpreferences.SharedPreferenceBooleanLiveData;
+import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.model.AccessControl;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
@@ -48,6 +52,10 @@ public class MainViewModel extends AndroidViewModel {
         this.syncManager = new SyncManager(application);
     }
 
+    public LiveData<Boolean> isDebugModeEnabled() {
+        return new SharedPreferenceBooleanLiveData(PreferenceManager.getDefaultSharedPreferences(getApplication()), getApplication().getString(R.string.pref_key_debugging), false);
+    }
+
     public Account getCurrentAccount() {
         return currentAccount.getValue();
     }
@@ -58,7 +66,7 @@ public class MainViewModel extends AndroidViewModel {
 
     public void setCurrentAccount(Account currentAccount) {
         this.currentAccount.setValue(currentAccount);
-        this.currentAccountIsSupportedVersion = currentAccount.getServerDeckVersionAsObject().isSupported(getApplication().getApplicationContext());
+        this.currentAccountIsSupportedVersion = currentAccount.getServerDeckVersionAsObject().isSupported();
     }
 
     public void setCurrentBoard(@NonNull Board currentBoard) {
@@ -127,12 +135,12 @@ public class MainViewModel extends AndroidViewModel {
         return syncManager.readAccounts();
     }
 
-    public WrappedLiveData<FullBoard> createBoard(long accountId, @NonNull Board board) {
-        return syncManager.createBoard(accountId, board);
+    public void createBoard(long accountId, @NonNull Board board, @NonNull ResponseCallback<FullBoard> callback) {
+        syncManager.createBoard(accountId, board, callback);
     }
 
-    public WrappedLiveData<FullBoard> updateBoard(@NonNull FullBoard board) {
-        return syncManager.updateBoard(board);
+    public void updateBoard(@NonNull FullBoard board, @NonNull ResponseCallback<FullBoard> callback) {
+        syncManager.updateBoard(board, callback);
     }
 
     public LiveData<List<Board>> getBoards(long accountId, boolean archived) {
@@ -143,64 +151,64 @@ public class MainViewModel extends AndroidViewModel {
         return syncManager.getFullBoardById(accountId, localId);
     }
 
-    public WrappedLiveData<FullBoard> archiveBoard(@NonNull Board board) {
-        return syncManager.archiveBoard(board);
+    public void archiveBoard(@NonNull Board board, @NonNull ResponseCallback<FullBoard> callback) {
+        syncManager.archiveBoard(board, callback);
     }
 
-    public WrappedLiveData<FullBoard> dearchiveBoard(@NonNull Board board) {
-        return syncManager.dearchiveBoard(board);
+    public void dearchiveBoard(@NonNull Board board, @NonNull ResponseCallback<FullBoard> callback) {
+        syncManager.dearchiveBoard(board, callback);
     }
 
-    public WrappedLiveData<FullBoard> cloneBoard(long originAccountId, long originBoardLocalId, long targetAccountId, @ColorInt int targetBoardColor, boolean cloneCards) {
-        return syncManager.cloneBoard(originAccountId, originBoardLocalId, targetAccountId, targetBoardColor, cloneCards);
+    public void cloneBoard(long originAccountId, long originBoardLocalId, long targetAccountId, @ColorInt int targetBoardColor, boolean cloneCards, @NonNull ResponseCallback<FullBoard> callback) {
+        syncManager.cloneBoard(originAccountId, originBoardLocalId, targetAccountId, targetBoardColor, cloneCards, callback);
     }
 
-    public WrappedLiveData<Void> deleteBoard(@NonNull Board board) {
-        return syncManager.deleteBoard(board);
+    public void deleteBoard(@NonNull Board board, @NonNull ResponseCallback<Void> callback) {
+        syncManager.deleteBoard(board, callback);
     }
 
     public LiveData<Boolean> hasArchivedBoards(long accountId) {
         return syncManager.hasArchivedBoards(accountId);
     }
 
-    public WrappedLiveData<AccessControl> createAccessControl(long accountId, AccessControl entity) {
-        return syncManager.createAccessControl(accountId, entity);
+    public void createAccessControl(long accountId, @NonNull AccessControl entity, @NonNull ResponseCallback<AccessControl> callback) {
+        syncManager.createAccessControl(accountId, entity, callback);
     }
 
-    public WrappedLiveData<AccessControl> updateAccessControl(@NonNull AccessControl entity) {
-        return syncManager.updateAccessControl(entity);
+    public void updateAccessControl(@NonNull AccessControl entity, @NonNull ResponseCallback<AccessControl> callback) {
+        syncManager.updateAccessControl(entity, callback);
     }
 
     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 void deleteAccessControl(@NonNull AccessControl entity, @NonNull ResponseCallback<Void> callback) {
+        syncManager.deleteAccessControl(entity, callback);
     }
 
-    public WrappedLiveData<Label> createLabel(long accountId, Label label, long localBoardId) {
-        return syncManager.createLabel(accountId, label, localBoardId);
+    public void createLabel(long accountId, Label label, long localBoardId, @NonNull ResponseCallback<Label> callback) {
+        syncManager.createLabel(accountId, label, localBoardId, callback);
     }
 
     public LiveData<Integer> countCardsWithLabel(long localLabelId) {
         return syncManager.countCardsWithLabel(localLabelId);
     }
 
-    public WrappedLiveData<Label> updateLabel(@NonNull Label label) {
-        return syncManager.updateLabel(label);
+    public void updateLabel(@NonNull Label label, @NonNull ResponseCallback<Label> callback) {
+        syncManager.updateLabel(label, callback);
     }
 
-    public WrappedLiveData<Void> deleteLabel(@NonNull Label label) {
-        return syncManager.deleteLabel(label);
+    public void deleteLabel(@NonNull Label label, @NonNull ResponseCallback<Void> callback) {
+        syncManager.deleteLabel(label, callback);
     }
 
     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 void createStack(long accountId, @NonNull String title, long boardLocalId, @NonNull ResponseCallback<FullStack> callback) {
+        syncManager.createStack(accountId, title, boardLocalId, callback);
     }
 
     public LiveData<FullStack> getStack(long accountId, long localStackId) {
@@ -211,12 +219,12 @@ public class MainViewModel extends AndroidViewModel {
         syncManager.swapStackOrder(accountId, boardLocalId, stackLocalIds);
     }
 
-    public WrappedLiveData<FullStack> updateStackTitle(long localStackId, @NonNull String newTitle) {
-        return syncManager.updateStackTitle(localStackId, newTitle);
+    public void updateStackTitle(long localStackId, @NonNull String newTitle, @NonNull ResponseCallback<FullStack> callback) {
+        syncManager.updateStackTitle(localStackId, newTitle, callback);
     }
 
-    public WrappedLiveData<Void> deleteStack(long accountId, long stackLocalId, long boardLocalId) {
-        return syncManager.deleteStack(accountId, stackLocalId, boardLocalId);
+    public void deleteStack(long accountId, long stackLocalId, long boardLocalId, @NonNull ResponseCallback<Void> callback) {
+        syncManager.deleteStack(accountId, stackLocalId, boardLocalId, callback);
     }
 
     public void reorder(long accountId, @NonNull FullCard movedCard, long newStackId, int newIndex) {
@@ -227,8 +235,8 @@ public class MainViewModel extends AndroidViewModel {
         return syncManager.countCardsInStack(accountId, localStackId);
     }
 
-    public WrappedLiveData<Void> archiveCardsInStack(long accountId, long stackLocalId, @NonNull FilterInformation filterInformation) {
-        return syncManager.archiveCardsInStack(accountId, stackLocalId, filterInformation);
+    public void archiveCardsInStack(long accountId, long stackLocalId, @NonNull FilterInformation filterInformation, @NonNull ResponseCallback<Void> callback) {
+        syncManager.archiveCardsInStack(accountId, stackLocalId, filterInformation, callback);
     }
 
     public WrappedLiveData<FullCard> updateCard(@NonNull FullCard fullCard) {
@@ -239,8 +247,8 @@ public class MainViewModel extends AndroidViewModel {
         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 addAttachmentToCard(long accountId, long localCardId, @NonNull String mimeType, @NonNull File file, @NonNull ResponseCallback<Attachment> callback) {
+        syncManager.addAttachmentToCard(accountId, localCardId, mimeType, file, callback);
     }
 
     public void addOrUpdateSingleCardWidget(int widgetId, long accountId, long boardId, long localCardId) {
@@ -271,15 +279,15 @@ public class MainViewModel extends AndroidViewModel {
         return syncManager.getUserByUidDirectly(accountId, uid);
     }
 
-    public WrappedLiveData<FullCard> archiveCard(@NonNull FullCard card) {
-        return syncManager.archiveCard(card);
+    public void archiveCard(@NonNull FullCard card, @NonNull ResponseCallback<FullCard> callback) {
+        syncManager.archiveCard(card, callback);
     }
 
-    public WrappedLiveData<FullCard> dearchiveCard(@NonNull FullCard card) {
-        return syncManager.dearchiveCard(card);
+    public void dearchiveCard(@NonNull FullCard card, @NonNull ResponseCallback<FullCard> callback) {
+        syncManager.dearchiveCard(card, callback);
     }
 
-    public WrappedLiveData<Void> deleteCard(@NonNull Card card) {
-        return syncManager.deleteCard(card);
+    public void deleteCard(@NonNull Card card, @NonNull ResponseCallback<Void> callback) {
+        syncManager.deleteCard(card, callback);
     }
 }
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
index 2339a8783..d60ce4002 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/PickStackActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/PickStackActivity.java
@@ -1,6 +1,5 @@
 package it.niedermann.nextcloud.deck.ui;
 
-import android.content.Intent;
 import android.content.res.ColorStateList;
 import android.graphics.Color;
 import android.os.Bundle;
@@ -31,7 +30,6 @@ 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 {
@@ -39,8 +37,6 @@ public abstract class PickStackActivity extends AppCompatActivity implements Bra
     protected ActivityPickStackBinding binding;
     protected PickStackViewModel viewModel;
 
-    private boolean brandingEnabled;
-
     private Account selectedAccount;
     private Board selectedBoard;
     private Stack selectedStack;
@@ -52,8 +48,6 @@ public abstract class PickStackActivity extends AppCompatActivity implements Bra
 
         Thread.setDefaultUncaughtExceptionHandler(new ExceptionHandler(this));
 
-        brandingEnabled = isBrandingEnabled(this);
-
         binding = ActivityPickStackBinding.inflate(getLayoutInflater());
         viewModel = new ViewModelProvider(this).get(PickStackViewModel.class);
 
@@ -64,7 +58,7 @@ public abstract class PickStackActivity extends AppCompatActivity implements Bra
             if (hasAccounts) {
                 return viewModel.readAccounts();
             } else {
-                startActivityForResult(new Intent(this, ImportAccountActivity.class), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
+                startActivityForResult(ImportAccountActivity.createIntent(this), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
                 return null;
             }
         }).observe(this, (List<Account> accounts) -> {
@@ -96,20 +90,18 @@ public abstract class PickStackActivity extends AppCompatActivity implements Bra
     @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));
-            }
+            @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 void onSubmit(Account account, long boardLocalId, 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 cdc20ed50..280ecebd8 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
@@ -18,6 +18,7 @@ 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.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.ProjectUtil;
 
@@ -40,8 +41,9 @@ public class PushNotificationActivity extends AppCompatActivity {
         super.onResume();
 
         Thread.currentThread().setUncaughtExceptionHandler(new ExceptionHandler(this));
+        final Intent intent = getIntent();
 
-        if (getIntent() == null) {
+        if (intent == null) {
             throw new IllegalArgumentException("Could not retrieve intent");
         }
 
@@ -51,101 +53,113 @@ public class PushNotificationActivity extends AppCompatActivity {
         setContentView(binding.getRoot());
         setSupportActionBar(binding.toolbar);
 
-        binding.subject.setText(getIntent().getStringExtra(KEY_SUBJECT));
+        binding.subject.setText(intent.getStringExtra(KEY_SUBJECT));
 
-        final String message = getIntent().getStringExtra(KEY_MESSAGE);
+        final String message = intent.getStringExtra(KEY_MESSAGE);
         if (!TextUtils.isEmpty(message)) {
             binding.message.setText(message);
             binding.message.setVisibility(View.VISIBLE);
         }
 
-        final String link = getIntent().getStringExtra(KEY_LINK);
-        long[] ids = ProjectUtil.extractBoardIdAndCardIdFromUrl(link);
-
-        binding.cancel.setOnClickListener((v) -> finish());
-
-        final String cardRemoteIdString = getIntent().getStringExtra(KEY_CARD_REMOTE_ID);
-        final String accountString = getIntent().getStringExtra(KEY_ACCOUNT);
-
-        DeckLog.verbose("cardRemoteIdString = " + cardRemoteIdString);
-        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);
+        final String link = intent.getStringExtra(KEY_LINK);
+        final long[] ids;
+        try {
+            ids = ProjectUtil.extractBoardIdAndCardIdFromUrl(link);
+
+            binding.cancel.setOnClickListener((v) -> finish());
+
+            final String cardRemoteIdString = intent.getStringExtra(KEY_CARD_REMOTE_ID);
+            final String accountString = intent.getStringExtra(KEY_ACCOUNT);
+
+            DeckLog.verbose("cardRemoteIdString = ", cardRemoteIdString);
+            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);
             }
-        } else {
-            DeckLog.warn("Link does not contain two IDs (expected one board id and one card id): " + link);
-            fallbackToBrowser(link);
+        } catch (Throwable t) {
+            final String params = "Error while receiving push notification:\n"
+                    + KEY_SUBJECT + ": [" + intent.getStringExtra(KEY_SUBJECT) + "]\n"
+                    + KEY_MESSAGE + ": [" + intent.getStringExtra(KEY_MESSAGE) + "]\n"
+                    + KEY_LINK + ": [" + intent.getStringExtra(KEY_LINK) + "]\n"
+                    + KEY_CARD_REMOTE_ID + ": [" + intent.getStringExtra(KEY_CARD_REMOTE_ID) + "]\n"
+                    + KEY_ACCOUNT + ": [" + intent.getStringExtra(KEY_ACCOUNT) + "]";
+            ExceptionDialogFragment.newInstance(new Exception(params, t), null).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            DeckLog.logError(t);
         }
     }
 
@@ -182,7 +196,7 @@ public class PushNotificationActivity extends AppCompatActivity {
 
     @UiThread
     private void launchEditActivity(@NonNull Account account, Long boardId, Long cardId) {
-        DeckLog.info("starting " + EditActivity.class.getSimpleName() + " with [" + account + ", " + boardId + ", " + cardId + "]");
+        DeckLog.info("starting", EditActivity.class.getSimpleName(), "with [" + account + ", " + boardId + ", " + cardId + "]");
         startActivity(EditActivity.createEditCardIntent(this, account, boardId, cardId));
         finish();
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutActivity.java
index bf3734b72..c37d0bc46 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutActivity.java
@@ -6,22 +6,22 @@ import android.os.Bundle;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.appcompat.app.AppCompatActivity;
 import androidx.fragment.app.Fragment;
-import androidx.fragment.app.FragmentManager;
-import androidx.lifecycle.Lifecycle;
+import androidx.fragment.app.FragmentActivity;
 import androidx.viewpager2.adapter.FragmentStateAdapter;
 
 import com.google.android.material.tabs.TabLayoutMediator;
 
+import it.niedermann.nextcloud.deck.DeckApplication;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ActivityAboutBinding;
 import it.niedermann.nextcloud.deck.model.Account;
-import it.niedermann.nextcloud.deck.ui.branding.BrandedActivity;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
 
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.applyBrandToPrimaryTabLayout;
 
-public class AboutActivity extends BrandedActivity {
+public class AboutActivity extends AppCompatActivity {
     private static final String BUNDLE_KEY_ACCOUNT = "account";
 
     private ActivityAboutBinding binding;
@@ -39,11 +39,11 @@ public class AboutActivity extends BrandedActivity {
         binding = ActivityAboutBinding.inflate(getLayoutInflater());
         setContentView(binding.getRoot());
 
+        DeckApplication.readCurrentAccountColor().observe(this, (mainColor) -> applyBrandToPrimaryTabLayout(mainColor, binding.tabLayout));
+
         setSupportActionBar(binding.toolbar);
-        binding.viewPager.setAdapter(new TabsPagerAdapter(getSupportFragmentManager(), getLifecycle(), (Account) getIntent().getSerializableExtra(BUNDLE_KEY_ACCOUNT)));
+        binding.viewPager.setAdapter(new TabsPagerAdapter(this, (Account) getIntent().getSerializableExtra(BUNDLE_KEY_ACCOUNT)));
         new TabLayoutMediator(binding.tabLayout, binding.viewPager, (tab, position) -> tab.setText(tabTitles[position])).attach();
-
-        setResult(RESULT_OK);
     }
 
     private static class TabsPagerAdapter extends FragmentStateAdapter {
@@ -51,8 +51,8 @@ public class AboutActivity extends BrandedActivity {
         @Nullable
         private final Account account;
 
-        TabsPagerAdapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle, @Nullable Account account) {
-            super(fragmentManager, lifecycle);
+        TabsPagerAdapter(final FragmentActivity fa, @Nullable Account account) {
+            super(fa);
             this.account = account;
         }
 
@@ -83,11 +83,6 @@ public class AboutActivity extends BrandedActivity {
         return true;
     }
 
-    @Override
-    public void applyBrand(int mainColor) {
-        applyBrandToPrimaryTabLayout(mainColor, binding.tabLayout);
-    }
-
     @NonNull
     public static Intent createIntent(@NonNull Context context, @NonNull Account account) {
         return new Intent(context, AboutActivity.class)
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutFragmentCreditsTab.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutFragmentCreditsTab.java
index 0b0f26e63..6dac2a2a1 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutFragmentCreditsTab.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/about/AboutFragmentCreditsTab.java
@@ -55,7 +55,7 @@ public class AboutFragmentCreditsTab extends Fragment {
         binding.lastBackgroundSync.setText(
                 lastBackgroundSync == BACKGROUND_SYNC_NEVER_EXECUTED || settingsBackgroundSync.equals(backgroundSyncOffValue)
                         ? disabled(getString(R.string.simple_disabled), requireContext())
-                        : strong(DateUtil.getRelativeDateTimeString(getContext(), lastBackgroundSync))
+                        : strong(DateUtil.getRelativeDateTimeString(requireContext(), lastBackgroundSync))
         );
         binding.aboutMaintainer.setText(url(getString(R.string.about_maintainer), getString(R.string.url_maintainer)));
         binding.aboutMaintainer.setMovementMethod(new LinkMovementMethod());
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 0bd92bc78..5e7b7a1ec 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
@@ -11,19 +11,21 @@ import android.view.ViewGroup;
 
 import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.core.content.ContextCompat;
 import androidx.core.graphics.drawable.DrawableCompat;
+import androidx.fragment.app.Fragment;
 
 import it.niedermann.android.util.ColorUtil;
+import it.niedermann.nextcloud.deck.DeckApplication;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.FragmentAboutLicenseTabBinding;
-import it.niedermann.nextcloud.deck.ui.branding.BrandedFragment;
 
 import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
 import static it.niedermann.nextcloud.deck.util.DeckColorUtil.contrastRatioIsSufficientBigAreas;
 import static it.niedermann.nextcloud.deck.util.SpannableUtil.setTextWithURL;
 
-public class AboutFragmentLicenseTab extends BrandedFragment {
+public class AboutFragmentLicenseTab extends Fragment {
 
     private FragmentAboutLicenseTabBinding binding;
 
@@ -37,11 +39,14 @@ public class AboutFragmentLicenseTab extends BrandedFragment {
     }
 
     @Override
-    public void applyBrand(int mainColor) {
-        @ColorInt final int finalMainColor = contrastRatioIsSufficientBigAreas(mainColor, ContextCompat.getColor(requireContext(), R.color.primary))
-                ? mainColor
-                : isDarkTheme(requireContext()) ? Color.WHITE : Color.BLACK;
-        DrawableCompat.setTintList(binding.aboutAppLicenseButton.getBackground(), ColorStateList.valueOf(finalMainColor));
-        binding.aboutAppLicenseButton.setTextColor(ColorUtil.INSTANCE.getForegroundColorForBackgroundColor(finalMainColor));
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+        DeckApplication.readCurrentAccountColor().observe(getViewLifecycleOwner(), (mainColor) -> {
+            @ColorInt final int finalMainColor = contrastRatioIsSufficientBigAreas(mainColor, ContextCompat.getColor(requireContext(), R.color.primary))
+                    ? mainColor
+                    : isDarkTheme(requireContext()) ? Color.WHITE : Color.BLACK;
+            DrawableCompat.setTintList(binding.aboutAppLicenseButton.getBackground(), ColorStateList.valueOf(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 744498c4a..8a70cf12d 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.Intent;
 import android.net.Uri;
 import android.os.Bundle;
 
@@ -26,7 +25,6 @@ import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
 import it.niedermann.nextcloud.deck.ui.manageaccounts.ManageAccountsActivity;
 
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
-import static it.niedermann.nextcloud.deck.ui.MainActivity.ACTIVITY_MANAGE_ACCOUNTS;
 
 public class AccountSwitcherDialog extends BrandedDialogFragment {
 
@@ -80,7 +78,7 @@ public class AccountSwitcherDialog extends BrandedDialogFragment {
         });
 
         binding.manageAccounts.setOnClickListener((v) -> {
-            requireActivity().startActivityForResult(new Intent(requireContext(), ManageAccountsActivity.class), ACTIVITY_MANAGE_ACCOUNTS);
+            requireActivity().startActivity(ManageAccountsActivity.createIntent(requireContext()));
             dismiss();
         });
 
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 d6d9cac1e..5a198dec3 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
@@ -10,12 +10,13 @@ import androidx.lifecycle.ViewModelProvider;
 
 import java.util.Collections;
 
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.databinding.ActivityArchivedBinding;
 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;
@@ -24,8 +25,6 @@ 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";
@@ -58,14 +57,7 @@ public class ArchivedBoardsActvitiy extends BrandedActivity implements DeleteBoa
         viewModel = new ViewModelProvider(this).get(MainViewModel.class);
         viewModel.setCurrentAccount(account);
 
-        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());
-                }
-            });
-        });
+        adapter = new ArchivedBoardsAdapter(viewModel.isCurrentAccountIsSupportedVersion(), getSupportFragmentManager(), this::onArchive);
         binding.recyclerView.setAdapter(adapter);
 
         viewModel.getBoards(account.getId(), true).observe(this, (boards) -> {
@@ -89,36 +81,62 @@ public class ArchivedBoardsActvitiy extends BrandedActivity implements DeleteBoa
 
     @Override
     public void onBoardDeleted(Board 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());
+        viewModel.deleteBoard(board, new ResponseCallback<Void>() {
+            @Override
+            public void onResponse(Void response) {
+                DeckLog.info("Successfully deleted board", board.getTitle());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                    ResponseCallback.super.onError(throwable);
+                    runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, viewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
+                }
             }
         });
     }
 
     @Override
     public void onUpdateBoard(FullBoard 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());
+        viewModel.updateBoard(fullBoard, new ResponseCallback<FullBoard>() {
+            @Override
+            public void onResponse(FullBoard response) {
+                DeckLog.info("Successfully updated board", fullBoard.getBoard().getTitle());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                ResponseCallback.super.onError(throwable);
+                runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, viewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
             }
         });
     }
 
     @Override
     public void onArchive(Board 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());
+        viewModel.dearchiveBoard(board, new ResponseCallback<FullBoard>() {
+            @Override
+            public void onResponse(FullBoard response) {
+                DeckLog.info("Successfully dearchived board", response.getBoard().getTitle());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                ResponseCallback.super.onError(throwable);
+                runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, viewModel.getCurrentAccount()).show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
             }
         });
     }
 
     @Override
     public void onClone(Board board) {
+        throw new IllegalStateException("Cloning boards is not available at " + ArchivedBoardsActvitiy.class.getSimpleName());
+    }
 
+    @Override
+    public boolean onSupportNavigateUp() {
+        finish(); // close this activity as oppose to navigating up
+        return true;
     }
 }
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 b5034ebfa..8968cbd72 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
@@ -1,28 +1,28 @@
 package it.niedermann.nextcloud.deck.ui.archivedcards;
 
-import android.content.Context;
+import android.app.Activity;
 import android.view.MenuItem;
 
 import androidx.annotation.NonNull;
 import androidx.fragment.app.FragmentManager;
 import androidx.lifecycle.LifecycleOwner;
 
+import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
+import it.niedermann.nextcloud.deck.model.Card;
 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.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 MainViewModel viewModel, @NonNull LifecycleOwner lifecycleOwner) {
-        super(context, fragmentManager, 0L, viewModel, lifecycleOwner, null);
+    public ArchivedCardsAdapter(@NonNull Activity activity, @NonNull FragmentManager fragmentManager, @NonNull MainViewModel viewModel, @NonNull LifecycleOwner lifecycleOwner) {
+        super(activity, fragmentManager, 0L, viewModel, lifecycleOwner, null);
     }
 
     @Override
@@ -34,18 +34,32 @@ public class ArchivedCardsAdapter extends CardAdapter {
     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());
+            mainViewModel.dearchiveCard(fullCard, new ResponseCallback<FullCard>() {
+                @Override
+                public void onResponse(FullCard response) {
+                    DeckLog.info("Successfully dearchived", Card.class.getSimpleName(), fullCard.getCard().getTitle());
+                }
+
+                @Override
+                public void onError(Throwable throwable) {
+                    ResponseCallback.super.onError(throwable);
+                    activity.runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, 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());
+            mainViewModel.deleteCard(fullCard.getCard(), new ResponseCallback<Void>() {
+                @Override
+                public void onResponse(Void response) {
+                    DeckLog.info("Successfully deleted card", fullCard.getCard().getTitle());
+                }
+
+                @Override
+                public void onError(Throwable throwable) {
+                    if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                        ResponseCallback.super.onError(throwable);
+                        activity.runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, mainViewModel.getCurrentAccount()).show(fragmentManager, ExceptionDialogFragment.class.getSimpleName()));
+                    }
                 }
             });
             return true;
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 6f4fe3c74..336e085d7 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
@@ -2,7 +2,6 @@ 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;
@@ -37,12 +36,10 @@ public class AttachmentViewHolder extends RecyclerView.ViewHolder {
 
     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.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());
+                final String uri = AttachmentUtil.getThumbnailUrl(account, cardRemoteId, attachment, binding.preview.getWidth(), binding.preview.getHeight());
                 Glide.with(parentContext)
                         .load(uri)
                         .listener(new RequestListener<Drawable>() {
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 6618f7f72..b65b727aa 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
@@ -50,7 +50,7 @@ public class AttachmentsActivity extends AppCompatActivity {
         supportPostponeEnterTransition();
 
         setSupportActionBar(binding.toolbar);
-        final Drawable navigationIcon = getResources().getDrawable(R.drawable.ic_arrow_back_white_24dp);
+        final Drawable navigationIcon = ContextCompat.getDrawable(this, R.drawable.ic_arrow_back_white_24dp);
         DrawableCompat.setTint(navigationIcon, ContextCompat.getColor(this, android.R.color.white));
         binding.toolbar.setNavigationIcon(navigationIcon);
 
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 0a1281fae..e120c665c 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
@@ -28,7 +28,6 @@ import it.niedermann.nextcloud.deck.ui.branding.Branded;
 import it.niedermann.nextcloud.deck.util.ViewUtil;
 
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
 
 public class AccessControlAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> implements Branded {
 
@@ -93,7 +92,8 @@ public class AccessControlAdapter extends RecyclerView.Adapter<RecyclerView.View
                 ViewUtil.addAvatar(acHolder.binding.avatar, account.getUrl(), ac.getUser().getUid(), R.drawable.ic_person_grey600_24dp);
 
                 acHolder.binding.username.setText(ac.getUser().getDisplayname());
-                acHolder.binding.username.setCompoundDrawables(null, null, ac.getStatus() == DBStatus.LOCAL_EDITED.getId() ? context.getResources().getDrawable(R.drawable.ic_sync_blue_24dp) : null, null);
+                acHolder.binding.username.setCompoundDrawables(null, null, ac.getStatus() == DBStatus.LOCAL_EDITED.getId()
+                        ? ContextCompat.getDrawable(context, R.drawable.ic_sync_blue_24dp) : null, null);
                 acHolder.binding.delete.setOnClickListener((v) -> accessControlChangedListener.deleteAccessControl(ac));
 
                 if (hasManagePermission) {
@@ -122,13 +122,11 @@ public class AccessControlAdapter extends RecyclerView.Adapter<RecyclerView.View
                     accessControlChangedListener.updateAccessControl(ac);
                 });
 
-                if (isBrandingEnabled(context)) {
-                    if (hasManagePermission) {
-                        brandSwitch(context, acHolder.binding.permissionEdit, mainColor);
-                        brandSwitch(context, acHolder.binding.permissionManage, mainColor);
-                    }
-                    brandSwitch(context, acHolder.binding.permissionShare, mainColor);
+                if (hasManagePermission) {
+                    brandSwitch(context, acHolder.binding.permissionEdit, mainColor);
+                    brandSwitch(context, acHolder.binding.permissionManage, mainColor);
                 }
+                brandSwitch(context, acHolder.binding.permissionShare, mainColor);
                 break;
             }
         }
@@ -160,10 +158,8 @@ public class AccessControlAdapter extends RecyclerView.Adapter<RecyclerView.View
 
     @Override
     public void applyBrand(int mainColor) {
-        if (isBrandingEnabled(context)) {
-            this.mainColor = getSecondaryForegroundColorDependingOnTheme(context, mainColor);
-            notifyDataSetChanged();
-        }
+        this.mainColor = getSecondaryForegroundColorDependingOnTheme(context, mainColor);
+        notifyDataSetChanged();
     }
 
     /**
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 78ccd5333..44bbcfe19 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
@@ -18,12 +18,12 @@ import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.databinding.DialogBoardShareBinding;
 import it.niedermann.nextcloud.deck.model.AccessControl;
 import it.niedermann.nextcloud.deck.model.User;
 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.branding.BrandedAlertDialogBuilder;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedDialogFragment;
@@ -31,7 +31,6 @@ import it.niedermann.nextcloud.deck.ui.branding.BrandedSnackbar;
 import it.niedermann.nextcloud.deck.ui.card.UserAutoCompleteAdapter;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 
-import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
 import static it.niedermann.nextcloud.deck.ui.board.accesscontrol.AccessControlAdapter.HEADER_ITEM_LOCAL_ID;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.applyBrandToEditText;
 
@@ -101,26 +100,39 @@ public class AccessControlDialogFragment extends BrandedDialogFragment implement
 
     @Override
     public void updateAccessControl(AccessControl 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());
+        viewModel.updateAccessControl(accessControl, new ResponseCallback<AccessControl>() {
+            @Override
+            public void onResponse(AccessControl response) {
+                DeckLog.info("Successfully updated", AccessControl.class.getSimpleName(), "for user", accessControl.getUser().getDisplayname());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                ResponseCallback.super.onError(throwable);
+                requireActivity().runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, viewModel.getCurrentAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
             }
         });
     }
 
     @Override
     public void deleteAccessControl(AccessControl ac) {
-        final WrappedLiveData<Void> wrappedDeleteLiveData = viewModel.deleteAccessControl(ac);
-        adapter.remove(ac);
-        observeOnce(wrappedDeleteLiveData, this, (ignored) -> {
-            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()))
-                        .show();
+        viewModel.deleteAccessControl(ac, new ResponseCallback<Void>() {
+            @Override
+            public void onResponse(Void response) {
+                DeckLog.info("Successfully deleted access control for user", ac.getUser().getDisplayname());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                    ResponseCallback.super.onError(throwable);
+                    requireActivity().runOnUiThread(() -> BrandedSnackbar.make(requireView(), getString(R.string.error_revoking_ac, ac.getUser().getDisplayname()), Snackbar.LENGTH_LONG)
+                            .setAction(R.string.simple_more, v -> ExceptionDialogFragment.newInstance(throwable, viewModel.getCurrentAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName()))
+                            .show());
+                }
             }
         });
+        adapter.remove(ac);
     }
 
     @Override
@@ -132,10 +144,16 @@ 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);
-        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());
+        viewModel.createAccessControl(viewModel.getCurrentAccount().getId(), ac, new ResponseCallback<AccessControl>() {
+            @Override
+            public void onResponse(AccessControl response) {
+                DeckLog.info("Successfully created", AccessControl.class.getSimpleName(), "for user", user.getDisplayname());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                ResponseCallback.super.onError(throwable);
+                requireActivity().runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, viewModel.getCurrentAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
             }
         });
         binding.people.setText("");
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsAdapter.java
index d8bb57a11..d6b097d89 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/board/managelabels/ManageLabelsAdapter.java
@@ -5,6 +5,7 @@ import android.view.LayoutInflater;
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
+import androidx.core.content.ContextCompat;
 import androidx.recyclerview.widget.RecyclerView;
 
 import java.util.LinkedList;
@@ -17,7 +18,6 @@ import it.niedermann.nextcloud.deck.model.Label;
 import it.niedermann.nextcloud.deck.ui.branding.Branded;
 
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
 
 public class ManageLabelsAdapter extends RecyclerView.Adapter<ManageLabelsViewHolder> implements Branded {
 
@@ -33,7 +33,7 @@ public class ManageLabelsAdapter extends RecyclerView.Adapter<ManageLabelsViewHo
     ManageLabelsAdapter(@NonNull ManageLabelListener listener, @NonNull Context context) {
         this.listener = listener;
         this.context = context;
-        this.mainColor = context.getResources().getColor(R.color.primary);
+        this.mainColor = ContextCompat.getColor(context, R.color.primary);
         setHasStableIds(true);
     }
 
@@ -76,9 +76,7 @@ public class ManageLabelsAdapter extends RecyclerView.Adapter<ManageLabelsViewHo
 
     @Override
     public void applyBrand(int mainColor) {
-        if (isBrandingEnabled(context)) {
-            this.mainColor = getSecondaryForegroundColorDependingOnTheme(context, mainColor);
-            notifyDataSetChanged();
-        }
+        this.mainColor = getSecondaryForegroundColorDependingOnTheme(context, mainColor);
+        notifyDataSetChanged();
     }
 }
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 bc0d98ca3..51ba42dd6 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
@@ -15,10 +15,10 @@ import java.util.Random;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.databinding.DialogBoardManageLabelsBinding;
 import it.niedermann.nextcloud.deck.model.Label;
 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.BrandedAlertDialogBuilder;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedDeleteAlertDialogBuilder;
@@ -80,22 +80,26 @@ public class ManageLabelsDialogFragment extends BrandedDialogFragment implements
             label.setTitle(binding.addLabelTitle.getText().toString());
             label.setColor(colors[new Random().nextInt(colors.length)]);
 
-            WrappedLiveData<Label> createLiveData = viewModel.createLabel(viewModel.getCurrentAccount().getId(), label, boardId);
-            observeOnce(createLiveData, this, (createdLabel) -> {
-                if (createLiveData.hasError()) {
-                    final Throwable error = createLiveData.getError();
-                    assert error != null;
-                    if (error instanceof SQLiteConstraintException) {
+            viewModel.createLabel(viewModel.getCurrentAccount().getId(), label, boardId, new ResponseCallback<Label>() {
+                @Override
+                public void onResponse(Label response) {
+                    Toast.makeText(requireContext(), getString(R.string.tag_successfully_added, label.getTitle()), Toast.LENGTH_LONG).show();
+                    requireActivity().runOnUiThread(() -> {
+                        binding.fab.setEnabled(true);
+                        binding.addLabelTitle.setText(null);
+                    });
+                }
+
+                @Override
+                public void onError(Throwable throwable) {
+                    requireActivity().runOnUiThread(() -> binding.fab.setEnabled(true));
+                    if (throwable instanceof SQLiteConstraintException) {
                         Toast.makeText(requireContext(), getString(R.string.tag_already_exists, label.getTitle()), Toast.LENGTH_LONG).show();
                     } else {
-                        Toast.makeText(requireContext(), error.getLocalizedMessage(), Toast.LENGTH_LONG).show();
-                        DeckLog.logError(error);
+                        Toast.makeText(requireContext(), throwable.getLocalizedMessage(), Toast.LENGTH_LONG).show();
+                        ResponseCallback.super.onError(throwable);
                     }
-                } else {
-                    binding.addLabelTitle.setText(null);
-                    Toast.makeText(requireContext(), getString(R.string.tag_successfully_added, label.getTitle()), Toast.LENGTH_LONG).show();
                 }
-                binding.fab.setEnabled(true);
             });
         });
         binding.addLabelTitle.setOnEditorActionListener((v, actionId, event) -> binding.fab.performClick());
@@ -139,13 +143,18 @@ public class ManageLabelsDialogFragment extends BrandedDialogFragment implements
     }
 
     private void deleteLabel(@NonNull Label label) {
-        final WrappedLiveData<Void> deleteLiveData = viewModel.deleteLabel(label);
-        observeOnce(deleteLiveData, this, (v) -> {
-            if (deleteLiveData.hasError() && !SyncManager.ignoreExceptionOnVoidError(deleteLiveData.getError())) {
-                final Throwable error = deleteLiveData.getError();
-                assert error != null;
-                Toast.makeText(requireContext(), error.getLocalizedMessage(), Toast.LENGTH_LONG).show();
-                DeckLog.logError(deleteLiveData.getError());
+        viewModel.deleteLabel(label, new ResponseCallback<Void>() {
+            @Override
+            public void onResponse(Void response) {
+                DeckLog.info("Successfully deleted label", label.getTitle());
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                    ResponseCallback.super.onError(throwable);
+                    Toast.makeText(requireContext(), throwable.getLocalizedMessage(), Toast.LENGTH_LONG).show();
+                }
             }
         });
     }
@@ -157,16 +166,19 @@ public class ManageLabelsDialogFragment extends BrandedDialogFragment implements
 
     @Override
     public void onLabelUpdated(@NonNull Label label) {
-        WrappedLiveData<Label> updateLiveData = viewModel.updateLabel(label);
-        observeOnce(updateLiveData, this, (updatedLabel) -> {
-            if (updateLiveData.hasError()) {
-                final Throwable error = updateLiveData.getError();
-                assert error != null;
+        viewModel.updateLabel(label, new ResponseCallback<Label>() {
+            @Override
+            public void onResponse(Label label) {
+                DeckLog.verbose("Successfully update label", label.getTitle());
+            }
+
+            @Override
+            public void onError(Throwable error) {
                 if (error instanceof SQLiteConstraintException) {
                     Toast.makeText(requireContext(), getString(R.string.tag_already_exists, label.getTitle()), Toast.LENGTH_LONG).show();
                 } else {
+                    ResponseCallback.super.onError(error);
                     Toast.makeText(requireContext(), error.getLocalizedMessage(), Toast.LENGTH_LONG).show();
-                    DeckLog.logError(updateLiveData.getError());
                 }
             }
         });
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedActivity.java
index 3420e888b..03c45305e 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedActivity.java
@@ -8,7 +8,6 @@ import androidx.appcompat.app.AppCompatActivity;
 
 import it.niedermann.nextcloud.deck.R;
 
-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.branding.BrandingUtil.tintMenuIcon;
 
@@ -25,10 +24,8 @@ public abstract class BrandedActivity extends AppCompatActivity implements Brand
         getTheme().resolveAttribute(R.attr.colorAccent, typedValue, true);
         colorAccent = typedValue.data;
 
-        if (isBrandingEnabled(this)) {
-            @ColorInt final int mainColor = readBrandMainColor(this);
-            applyBrand(mainColor);
-        }
+        @ColorInt final int mainColor = readBrandMainColor(this);
+        applyBrand(mainColor);
     }
 
     @Override
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 319df7f79..c84ac8274 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
@@ -21,7 +21,6 @@ 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;
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMainColor;
 
 public class BrandedDatePickerDialog extends DatePickerDialog implements Branded {
@@ -31,9 +30,7 @@ public class BrandedDatePickerDialog extends DatePickerDialog implements Branded
         @Nullable Context context = getContext();
         if (context != null) {
             setThemeDark(isDarkTheme(context));
-            if (isBrandingEnabled(context)) {
-                applyBrand(readBrandMainColor(context));
-            }
+            applyBrand(readBrandMainColor(context));
         }
         return super.onCreateView(inflater, container, savedInstanceState);
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDialogFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDialogFragment.java
index adf3844e9..28d4da9ee 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDialogFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedDialogFragment.java
@@ -5,7 +5,6 @@ import android.content.Context;
 import androidx.annotation.Nullable;
 import androidx.fragment.app.DialogFragment;
 
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMainColor;
 
 public abstract class BrandedDialogFragment extends DialogFragment implements Branded {
@@ -16,9 +15,7 @@ public abstract class BrandedDialogFragment extends DialogFragment implements Br
 
         @Nullable Context context = getContext();
         if (context != null) {
-            if (isBrandingEnabled(context)) {
-                applyBrand(readBrandMainColor(context));
-            }
+            applyBrand(readBrandMainColor(context));
         }
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedFragment.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedFragment.java
index fe202f48c..87cee2317 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedFragment.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedFragment.java
@@ -5,7 +5,6 @@ import android.content.Context;
 import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
 
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMainColor;
 
 public abstract class BrandedFragment extends Fragment implements Branded {
@@ -15,8 +14,6 @@ public abstract class BrandedFragment extends Fragment implements Branded {
         super.onStart();
 
         @Nullable Context context = getContext();
-        if (context != null && isBrandingEnabled(context)) {
-            applyBrand(readBrandMainColor(context));
-        }
+        applyBrand(readBrandMainColor(context));
     }
 }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedPreferenceCategory.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedPreferenceCategory.java
index e01c523c6..70db03aa0 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedPreferenceCategory.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedPreferenceCategory.java
@@ -10,9 +10,8 @@ import androidx.annotation.Nullable;
 import androidx.preference.PreferenceCategory;
 import androidx.preference.PreferenceViewHolder;
 
+import static it.niedermann.nextcloud.deck.DeckApplication.readCurrentAccountColor;
 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.ui.branding.BrandingUtil.readBrandMainColor;
 
 public class BrandedPreferenceCategory extends PreferenceCategory {
 
@@ -20,13 +19,11 @@ public class BrandedPreferenceCategory extends PreferenceCategory {
     public void onBindViewHolder(PreferenceViewHolder holder) {
         super.onBindViewHolder(holder);
 
-        if (isBrandingEnabled(getContext())) {
-            final View v = holder.itemView.findViewById(android.R.id.title);
-            @Nullable final Context context = getContext();
-            if (context != null && v instanceof TextView) {
-                @ColorInt final int mainColor = getSecondaryForegroundColorDependingOnTheme(context, readBrandMainColor(context));
-                ((TextView) v).setTextColor(mainColor);
-            }
+        final View v = holder.itemView.findViewById(android.R.id.title);
+        @Nullable final Context context = getContext();
+        if (context != null && v instanceof TextView) {
+            @ColorInt final int mainColor = getSecondaryForegroundColorDependingOnTheme(context, readCurrentAccountColor(context));
+            ((TextView) v).setTextColor(mainColor);
         }
     }
 
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 0159a59dc..8b4cf2f5a 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
@@ -6,15 +6,12 @@ import android.view.View;
 import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.StringRes;
-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 static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMainColor;
 
 public class BrandedSnackbar {
@@ -23,12 +20,8 @@ public class BrandedSnackbar {
     public static Snackbar make(
             @NonNull View view, @NonNull CharSequence text, @BaseTransientBottomBar.Duration int duration) {
         final Snackbar snackbar = Snackbar.make(view, text, duration);
-        if (isBrandingEnabled(view.getContext())) {
-            @ColorInt final int color = readBrandMainColor(view.getContext());
-            snackbar.setActionTextColor(ColorUtil.INSTANCE.isColorDark(color) ? Color.WHITE : color);
-        } else {
-            snackbar.setActionTextColor(ContextCompat.getColor(view.getContext(), R.color.defaultBrand));
-        }
+        @ColorInt final int color = readBrandMainColor(view.getContext());
+        snackbar.setActionTextColor(ColorUtil.INSTANCE.isColorDark(color) ? Color.WHITE : color);
         return snackbar;
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedSwitchPreference.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedSwitchPreference.java
index 463800a0a..607beba03 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedSwitchPreference.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/branding/BrandedSwitchPreference.java
@@ -16,7 +16,6 @@ import androidx.preference.SwitchPreference;
 import it.niedermann.nextcloud.deck.R;
 
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.getSecondaryForegroundColorDependingOnTheme;
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
 
 public class BrandedSwitchPreference extends SwitchPreference implements Branded {
 
@@ -46,7 +45,7 @@ public class BrandedSwitchPreference extends SwitchPreference implements Branded
     public void onBindViewHolder(PreferenceViewHolder holder) {
         super.onBindViewHolder(holder);
 
-        if (isBrandingEnabled(getContext()) && holder.itemView instanceof ViewGroup) {
+        if (holder.itemView instanceof ViewGroup) {
             switchView = findSwitchWidget(holder.itemView);
             if (mainColor != null) {
                 applyBrand();
@@ -58,9 +57,7 @@ public class BrandedSwitchPreference extends SwitchPreference implements Branded
     public void applyBrand(@ColorInt int mainColor) {
         this.mainColor = mainColor;
         // onBindViewHolder is called after applyBrand, therefore we have to store the given values and apply them later.
-        if (isBrandingEnabled(getContext())) {
-            applyBrand();
-        }
+        applyBrand();
     }
 
     private void applyBrand() {
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 2e0c4d3b8..02e09e3c8 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
@@ -21,7 +21,6 @@ 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;
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.isBrandingEnabled;
 import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMainColor;
 
 public class BrandedTimePickerDialog extends TimePickerDialog implements Branded {
@@ -31,9 +30,7 @@ public class BrandedTimePickerDialog extends TimePickerDialog implements Branded
         @Nullable Context context = getContext();
         if (context != null) {
             setThemeDark(isDarkTheme(context));
-            if (isBrandingEnabled(context)) {
-                applyBrand(readBrandMainColor(context));
-            }
+            applyBrand(readBrandMainColor(context));
         }
         return super.onCreateView(inflater, container, savedInstanceState);
     }
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 b780efec5..863375ae5 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
@@ -31,40 +31,31 @@ public abstract class BrandingUtil {
         // Util class
     }
 
-    public static boolean isBrandingEnabled(@NonNull Context context) {
-        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
-        return prefs.getBoolean(context.getString(R.string.pref_key_branding), true);
-    }
-
     @ColorInt
     public static int readBrandMainColor(@NonNull Context context) {
-        if (isBrandingEnabled(context)) {
-            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context.getApplicationContext());
-            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 ContextCompat.getColor(context, R.color.defaultBrand);
-        }
+        final SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context.getApplicationContext());
+        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));
     }
 
     public static void saveBrandColors(@NonNull Context context, @ColorInt int mainColor) {
-        if (isBrandingEnabled(context) && context instanceof BrandedActivity) {
+        if (context instanceof BrandedActivity) {
             final BrandedActivity activity = (BrandedActivity) context;
             activity.applyBrand(mainColor);
         }
-        SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
-        DeckLog.log("--- Write: shared_preference_theme_main" + " | " + mainColor);
+        final SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
+        DeckLog.log("--- Write: shared_preference_theme_main |", mainColor);
         editor.putInt(context.getString(R.string.shared_preference_theme_main), mainColor);
         editor.apply();
     }
 
     public static void clearBrandColors(@NonNull Context context) {
-        if (isBrandingEnabled(context) && context instanceof BrandedActivity) {
+        if (context instanceof BrandedActivity) {
             final BrandedActivity activity = (BrandedActivity) context;
             activity.applyBrand(ContextCompat.getColor(context, R.color.defaultBrand));
         }
-        SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
-        DeckLog.log("--- Write: Remove: shared_preference_theme_main" + " | ");
+        final SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(context).edit();
+        DeckLog.log("--- Write: Remove: shared_preference_theme_main | ");
         editor.remove(context.getString(R.string.shared_preference_theme_main));
         editor.apply();
     }
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 87140e544..1e92eb1b3 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
@@ -1,7 +1,7 @@
 package it.niedermann.nextcloud.deck.ui.card;
 
+import android.app.Activity;
 import android.content.ClipData;
-import android.content.Context;
 import android.content.Intent;
 import android.view.LayoutInflater;
 import android.view.MenuItem;
@@ -24,6 +24,7 @@ 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.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.databinding.ItemCardCompactBinding;
 import it.niedermann.nextcloud.deck.databinding.ItemCardDefaultBinding;
 import it.niedermann.nextcloud.deck.databinding.ItemCardDefaultOnlyTitleBinding;
@@ -32,14 +33,13 @@ 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.Branded;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 import it.niedermann.nextcloud.deck.ui.movecard.MoveCardDialogFragment;
+import it.niedermann.nextcloud.deck.util.CardUtil;
 
 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;
 
@@ -52,7 +52,7 @@ public class CardAdapter extends RecyclerView.Adapter<AbstractCardViewHolder> im
     protected final FragmentManager fragmentManager;
     private final long stackId;
     @NonNull
-    private final Context context;
+    protected final Activity activity;
     @Nullable
     private final SelectCardListener selectCardListener;
     @NonNull
@@ -66,17 +66,17 @@ public class CardAdapter extends RecyclerView.Adapter<AbstractCardViewHolder> im
     @StringRes
     private final int shareLinkRes;
 
-    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);
+    public CardAdapter(@NonNull Activity activity, @NonNull FragmentManager fragmentManager, long stackId, @NonNull MainViewModel mainViewModel, @NonNull LifecycleOwner lifecycleOwner, @Nullable SelectCardListener selectCardListener) {
+        this.activity = activity;
+        this.counterMaxValue = this.activity.getString(R.string.counter_max_value);
         this.fragmentManager = fragmentManager;
         this.lifecycleOwner = lifecycleOwner;
         this.shareLinkRes = mainViewModel.getCurrentAccount().getServerDeckVersionAsObject().getShareLinkResource();
         this.stackId = stackId;
         this.mainViewModel = mainViewModel;
         this.selectCardListener = selectCardListener;
-        this.mainColor = ContextCompat.getColor(context, R.color.defaultBrand);
-        this.compactMode = getDefaultSharedPreferences(context).getBoolean(context.getString(R.string.pref_key_compact), false);
+        this.mainColor = ContextCompat.getColor(this.activity, R.color.defaultBrand);
+        this.compactMode = getDefaultSharedPreferences(this.activity).getBoolean(this.activity.getString(R.string.pref_key_compact), false);
         setHasStableIds(true);
     }
 
@@ -120,7 +120,7 @@ public class CardAdapter extends RecyclerView.Adapter<AbstractCardViewHolder> im
         // 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, mainViewModel.getCurrentAccount(), mainViewModel.getCurrentBoardLocalId(), fullCard.getLocalId()));
+                activity.startActivity(EditActivity.createEditCardIntent(activity, mainViewModel.getCurrentAccount(), mainViewModel.getCurrentBoardLocalId(), fullCard.getLocalId()));
             } else {
                 selectCardListener.onCardSelected(fullCard);
             }
@@ -176,7 +176,7 @@ public class CardAdapter extends RecyclerView.Adapter<AbstractCardViewHolder> im
 
     @Override
     public void applyBrand(int mainColor) {
-        this.mainColor = getSecondaryForegroundColorDependingOnTheme(context, mainColor);
+        this.mainColor = getSecondaryForegroundColorDependingOnTheme(activity, mainColor);
         notifyDataSetChanged();
     }
 
@@ -185,15 +185,22 @@ public class CardAdapter extends RecyclerView.Adapter<AbstractCardViewHolder> im
         int itemId = menuItem.getItemId();
         final Account account = mainViewModel.getCurrentAccount();
         if (itemId == R.id.share_link) {
-            Intent shareIntent = new Intent()
+            final 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();
+                    .putExtra(Intent.EXTRA_TEXT, account.getUrl() + activity.getString(shareLinkRes, mainViewModel.getCurrentBoardRemoteId(), fullCard.getCard().getId()));
+            activity.startActivity(Intent.createChooser(shareIntent, fullCard.getCard().getTitle()));
             return true;
+        } else if (itemId == R.id.share_content) {
+            final 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, CardUtil.getCardContentAsString(activity, fullCard));
+            activity.startActivity(Intent.createChooser(shareIntent, fullCard.getCard().getTitle()));
         } else if (itemId == R.id.action_card_assign) {
             new Thread(() -> mainViewModel.assignUserToCard(mainViewModel.getUserByUidDirectly(fullCard.getCard().getAccountId(), account.getUserName()), fullCard.getCard())).start();
             return true;
@@ -202,21 +209,37 @@ public class CardAdapter extends RecyclerView.Adapter<AbstractCardViewHolder> im
             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());
+            MoveCardDialogFragment
+                    .newInstance(fullCard.getAccountId(), mainViewModel.getCurrentBoardLocalId(), fullCard.getCard().getTitle(), fullCard.getLocalId(), CardUtil.cardHasCommentsOrAttachments(fullCard))
+                    .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());
+            mainViewModel.archiveCard(fullCard, new ResponseCallback<FullCard>() {
+                @Override
+                public void onResponse(FullCard response) {
+                    DeckLog.info("Successfully archived", Card.class.getSimpleName(), fullCard.getCard().getTitle());
+                }
+
+                @Override
+                public void onError(Throwable throwable) {
+                    ResponseCallback.super.onError(throwable);
+                    activity.runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, account).show(fragmentManager, ExceptionDialogFragment.class.getSimpleName()));
                 }
             });
             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());
+            mainViewModel.deleteCard(fullCard.getCard(), new ResponseCallback<Void>() {
+                @Override
+                public void onResponse(Void response) {
+                    DeckLog.info("Successfully deleted card", fullCard.getCard().getTitle());
+                }
+
+                @Override
+                public void onError(Throwable throwable) {
+                    if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                        ResponseCallback.super.onError(throwable);
+                        activity.runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, account).show(fragmentManager, ExceptionDialogFragment.class.getSimpleName()));
+                    }
                 }
             });
             return true;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardTabAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardTabAdapter.java
index c0ed29007..68c95bfb6 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardTabAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/CardTabAdapter.java
@@ -2,8 +2,7 @@ package it.niedermann.nextcloud.deck.ui.card;
 
 import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
-import androidx.fragment.app.FragmentManager;
-import androidx.lifecycle.Lifecycle;
+import androidx.fragment.app.FragmentActivity;
 import androidx.viewpager2.adapter.FragmentStateAdapter;
 
 import it.niedermann.nextcloud.deck.ui.card.activities.CardActivityFragment;
@@ -15,9 +14,8 @@ public class CardTabAdapter extends FragmentStateAdapter {
 
     private boolean hasCommentsAbility = false;
 
-    @SuppressWarnings("WeakerAccess")
-    public CardTabAdapter(@NonNull FragmentManager fm, @NonNull Lifecycle lifecycle) {
-        super(fm, lifecycle);
+    public CardTabAdapter(final FragmentActivity fa) {
+        super(fa);
     }
 
     @NonNull
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 2e1ff5e06..15a1a6fb7 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
@@ -14,6 +14,7 @@ import android.view.MenuItem;
 import android.view.WindowManager;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.lifecycle.ViewModelProvider;
@@ -25,7 +26,10 @@ 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.model.Card;
 import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.model.ocs.Version;
+import it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.WrappedLiveData;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedActivity;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedAlertDialogBuilder;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
@@ -33,7 +37,6 @@ import it.niedermann.nextcloud.deck.util.CardUtil;
 
 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;
 
 public class EditActivity extends BrandedActivity {
     private static final String BUNDLE_KEY_ACCOUNT = "account";
@@ -41,6 +44,7 @@ public class EditActivity extends BrandedActivity {
     private static final String BUNDLE_KEY_STACK_ID = "stackId";
     private static final String BUNDLE_KEY_CARD_ID = "cardId";
     private static final String BUNDLE_KEY_TITLE = "title";
+    private static final String BUNDLE_KEY_DESCRIPTION = "description";
 
     private ActivityEditBinding binding;
     private EditCardViewModel viewModel;
@@ -76,12 +80,13 @@ public class EditActivity extends BrandedActivity {
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         Thread.currentThread().setUncaughtExceptionHandler(new ExceptionHandler(this));
+
         binding = ActivityEditBinding.inflate(getLayoutInflater());
+        viewModel = new ViewModelProvider(this).get(EditCardViewModel.class);
+
         setContentView(binding.getRoot());
         setSupportActionBar(binding.toolbar);
 
-        viewModel = new ViewModelProvider(this).get(EditCardViewModel.class);
-
         loadDataFromIntent();
     }
 
@@ -122,16 +127,10 @@ public class EditActivity extends BrandedActivity {
             viewModel.setCanEdit(fullBoard.getBoard().isPermissionEdit());
             invalidateOptionsMenu();
             if (viewModel.isCreateMode()) {
-                viewModel.initializeNewCard(boardId, args.getLong(BUNDLE_KEY_STACK_ID), account.getServerDeckVersionAsObject().isSupported(this));
+                viewModel.initializeNewCard(boardId, args.getLong(BUNDLE_KEY_STACK_ID), account.getServerDeckVersionAsObject().isSupported());
                 invalidateOptionsMenu();
-                String title = args.getString(BUNDLE_KEY_TITLE);
-                if (!TextUtils.isEmpty(title)) {
-                    if (title.length() > viewModel.getAccount().getServerDeckVersionAsObject().getCardTitleMaxLength()) {
-                        viewModel.getFullCard().getCard().setDescription(title);
-                    } else {
-                        viewModel.getFullCard().getCard().setTitle(title);
-                    }
-                }
+                fillTitleAndDescription(viewModel.getFullCard().getCard(), viewModel.getAccount().getServerDeckVersionAsObject(),
+                        args.getString(BUNDLE_KEY_TITLE), args.getString(BUNDLE_KEY_DESCRIPTION));
                 setupViewPager();
                 setupTitle();
             } else {
@@ -143,7 +142,7 @@ public class EditActivity extends BrandedActivity {
                                 .setPositiveButton(R.string.simple_close, (a, b) -> super.finish())
                                 .show();
                     } else {
-                        viewModel.initializeExistingCard(boardId, fullCard, account.getServerDeckVersionAsObject().isSupported(this));
+                        viewModel.initializeExistingCard(boardId, fullCard, account.getServerDeckVersionAsObject().isSupported());
                         invalidateOptionsMenu();
                         setupViewPager();
                         setupTitle();
@@ -152,7 +151,35 @@ public class EditActivity extends BrandedActivity {
             }
         }));
 
-        DeckLog.verbose("Finished loading intent data: { accountId = " + viewModel.getAccount().getId() + " , cardId = " + cardId + " }");
+        DeckLog.verbose("Finished loading intent data: { accountId =", viewModel.getAccount().getId(), "cardId =", cardId, "}");
+    }
+
+    private static void fillTitleAndDescription(@NonNull Card card, @NonNull Version version, @Nullable String title, @Nullable String description) {
+        if (!TextUtils.isEmpty(title) && !TextUtils.isEmpty(description)) {
+            assert title != null;
+            if (title.length() > version.getCardTitleMaxLength()) {
+                card.setTitle(title.substring(0, version.getCardTitleMaxLength()));
+            } else {
+                card.setTitle(title);
+            }
+            card.setDescription(description);
+        } else if (!TextUtils.isEmpty(title)) {
+            assert title != null;
+            if (title.length() > version.getCardTitleMaxLength()) {
+                card.setDescription(title);
+                card.setTitle(title.substring(0, version.getCardTitleMaxLength()));
+            } else {
+                card.setTitle(title);
+            }
+        } else if (!TextUtils.isEmpty(description)) {
+            assert description != null;
+            if (description.length() > version.getCardTitleMaxLength()) {
+                card.setDescription(description);
+                card.setTitle(description.substring(0, version.getCardTitleMaxLength()));
+            } else {
+                card.setTitle(description);
+            }
+        }
     }
 
     @Override
@@ -169,16 +196,21 @@ public class EditActivity extends BrandedActivity {
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         if (item.getItemId() == R.id.action_card_save) {
-            saveAndRun(super::finish);
+            saveAndFinish();
         }
         return super.onOptionsItemSelected(item);
     }
 
+    @Override
+    public boolean onSupportNavigateUp() {
+        finish(); // close this activity as oppose to navigating up
+        return true;
+    }
+
     /**
-     * Tries to save the current {@link FullCard} from the {@link EditCardViewModel} and then runs the given {@link Runnable}
-     * @param runnable
+     * Tries to save the current {@link FullCard} from the {@link EditCardViewModel} and then finishes this activity.
      */
-    private void saveAndRun(@NonNull Runnable runnable) {
+    private void saveAndFinish() {
         if (!viewModel.isPendingCreation()) {
             viewModel.setPendingCreation(true);
             final String title = viewModel.getFullCard().getCard().getTitle();
@@ -195,11 +227,13 @@ public class EditActivity extends BrandedActivity {
                         .setOnDismissListener(dialog -> viewModel.setPendingCreation(false))
                         .show();
             } else {
-                if (viewModel.isCreateMode()) {
-                    observeOnce(viewModel.createFullCard(viewModel.getAccount().getId(), viewModel.getBoardId(), viewModel.getFullCard().getCard().getStackId(), viewModel.getFullCard()), EditActivity.this, (card) -> runnable.run());
-                } else {
-                    observeOnce(viewModel.updateCard(viewModel.getFullCard()), EditActivity.this, (card) -> runnable.run());
-                }
+                final WrappedLiveData<FullCard> save$ = viewModel.saveCard();
+                save$.observe(this, (fullCard) -> {
+                    if (save$.hasError()) {
+                        DeckLog.logError(save$.getError());
+                    }
+                });
+                super.finish();
             }
         }
     }
@@ -208,7 +242,7 @@ public class EditActivity extends BrandedActivity {
         binding.tabLayout.removeAllTabs();
         binding.tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
 
-        final CardTabAdapter adapter = new CardTabAdapter(getSupportFragmentManager(), getLifecycle());
+        final CardTabAdapter adapter = new CardTabAdapter(this);
         final TabLayoutMediator mediator = new TabLayoutMediator(binding.tabLayout, binding.pager, (tab, position) -> {
             tab.setIcon(!viewModel.isCreateMode() && viewModel.hasCommentsAbility()
                     ? tabIconsWithComments[position]
@@ -272,7 +306,7 @@ public class EditActivity extends BrandedActivity {
             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) -> saveAndRun(super::finish))
+                    .setPositiveButton(R.string.simple_save, (dialog, whichButton) -> saveAndFinish())
                     .setNegativeButton(R.string.simple_discard, (dialog, whichButton) -> super.finish()).show();
         } else {
             super.finish();
@@ -288,39 +322,43 @@ public class EditActivity extends BrandedActivity {
 
     @Override
     public void applyBrand(int mainColor) {
-        if (isBrandingEnabled(this)) {
-            final Drawable navigationIcon = binding.toolbar.getNavigationIcon();
-            if (navigationIcon == null) {
-                DeckLog.error("Expected navigationIcon to be present.");
-            } else {
-                DrawableCompat.setTint(binding.toolbar.getNavigationIcon(), colorAccent);
-            }
-            applyBrandToPrimaryTabLayout(mainColor, binding.tabLayout);
+        final Drawable navigationIcon = binding.toolbar.getNavigationIcon();
+        if (navigationIcon == null) {
+            DeckLog.error("Expected navigationIcon to be present.");
+        } else {
+            DrawableCompat.setTint(binding.toolbar.getNavigationIcon(), colorAccent);
         }
+        applyBrandToPrimaryTabLayout(mainColor, binding.tabLayout);
+    }
+
+    @NonNull
+    public static Intent createNewCardIntent(@NonNull Context context, @NonNull Account account, Long boardLocalId, Long stackId, @Nullable String title, @Nullable String description) {
+        return createNewCardIntent(context, account, boardLocalId, stackId, title)
+                .putExtra(BUNDLE_KEY_DESCRIPTION, description);
     }
 
     @NonNull
-    public static Intent createNewCardIntent(@NonNull Context context, @NonNull Account account, Long boardId, Long stackId, @NonNull String title) {
-        return createNewCardIntent(context, account, boardId, stackId)
+    public static Intent createNewCardIntent(@NonNull Context context, @NonNull Account account, Long boardLocalId, Long stackId, @Nullable String title) {
+        return createNewCardIntent(context, account, boardLocalId, stackId)
                 .putExtra(BUNDLE_KEY_TITLE, title);
     }
 
     @NonNull
-    public static Intent createNewCardIntent(@NonNull Context context, @NonNull Account account, Long boardId, Long stackId) {
-        return createBasicIntent(context, account, boardId)
+    public static Intent createNewCardIntent(@NonNull Context context, @NonNull Account account, Long boardLocalId, Long stackId) {
+        return createBasicIntent(context, account, boardLocalId)
                 .putExtra(BUNDLE_KEY_STACK_ID, stackId);
     }
 
     @NonNull
-    public static Intent createEditCardIntent(@NonNull Context context, @NonNull Account account, Long boardId, Long cardId) {
-        return createBasicIntent(context, account, boardId)
+    public static Intent createEditCardIntent(@NonNull Context context, @NonNull Account account, Long boardLocalId, Long cardId) {
+        return createBasicIntent(context, account, boardLocalId)
                 .putExtra(BUNDLE_KEY_CARD_ID, cardId);
     }
 
-    private static Intent createBasicIntent(@NonNull Context context, @NonNull Account account, Long boardId) {
+    private static Intent createBasicIntent(@NonNull Context context, @NonNull Account account, Long boardLocalId) {
         return new Intent(context, EditActivity.class)
                 .putExtra(BUNDLE_KEY_ACCOUNT, account)
-                .putExtra(BUNDLE_KEY_BOARD_ID, boardId)
+                .putExtra(BUNDLE_KEY_BOARD_ID, boardLocalId)
                 .setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
     }
 }
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 c754d0800..321f70984 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
@@ -11,6 +11,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
 import it.niedermann.nextcloud.deck.model.Board;
@@ -130,32 +131,33 @@ public class EditCardViewModel extends AndroidViewModel {
         return syncManager.getFullBoardById(accountId, localId);
     }
 
-    public WrappedLiveData<Label> createLabel(long accountId, Label label, long localBoardId) {
-        return syncManager.createLabel(accountId, label, localBoardId);
+    public void createLabel(long accountId, Label label, long localBoardId, @NonNull ResponseCallback<Label> callback) {
+        syncManager.createLabel(accountId, label, localBoardId, callback);
     }
 
     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);
+    /**
+     * Saves the current {@link #fullCard}. If it is a new card, it will be created, otherwise it will be updated.
+     */
+    public WrappedLiveData<FullCard> saveCard() {
+        return isCreateMode()
+                ? syncManager.createFullCard(getAccount().getId(), getBoardId(), getFullCard().getCard().getStackId(), getFullCard())
+                : syncManager.updateCard(getFullCard());
     }
 
     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 void addAttachmentToCard(long accountId, long localCardId, @NonNull String mimeType, @NonNull File file, @NonNull ResponseCallback<Attachment> callback) {
+        syncManager.addAttachmentToCard(accountId, localCardId, mimeType, file, callback);
     }
 
-    public WrappedLiveData<Void> deleteAttachmentOfCard(long accountId, long localCardId, long localAttachmentId) {
-        return syncManager.deleteAttachmentOfCard(accountId, localCardId, localAttachmentId);
+    public void deleteAttachmentOfCard(long accountId, long localCardId, long localAttachmentId, @NonNull ResponseCallback<Void> callback) {
+        syncManager.deleteAttachmentOfCard(accountId, localCardId, localAttachmentId, callback);
     }
 
     public LiveData<Card> getCardByRemoteID(long accountId, long remoteId) {
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 fe974f2a0..de9d23829 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
@@ -12,6 +12,7 @@ import androidx.activity.ComponentActivity;
 import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.core.content.ContextCompat;
 import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.lifecycle.LiveData;
 
@@ -68,7 +69,7 @@ public class LabelAutoCompleteAdapter extends AutoCompleteAdapter<Label> {
         binding.label.setTextColor(color);
 
         if (ITEM_CREATE == label.getLocalId()) {
-            final Drawable plusIcon = DrawableCompat.wrap(binding.label.getContext().getResources().getDrawable(R.drawable.ic_plus));
+            final Drawable plusIcon = DrawableCompat.wrap(ContextCompat.getDrawable(binding.label.getContext(), R.drawable.ic_plus));
             DrawableCompat.setTint(plusIcon, color);
             binding.label.setChipIcon(plusIcon);
         } else {
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
index 34d2eb3f3..b18f35de0 100644
--- 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
@@ -24,10 +24,13 @@ 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 it.niedermann.nextcloud.deck.ui.card.attachments.previewdialog.PreviewDialog;
 
 import static it.niedermann.nextcloud.deck.DeckApplication.isDarkTheme;
 
-@Deprecated
+/**
+ * TODO maybe this can be merged with {@link PreviewDialog}
+ */
 public class CardAssigneeDialog extends BrandedDialogFragment {
 
     private static final String KEY_USER = "user";
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 533bbe322..51087584e 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
@@ -17,6 +17,7 @@ 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.model.enums.EAttachmentType;
 import it.niedermann.nextcloud.deck.ui.branding.BrandingUtil;
 import it.niedermann.nextcloud.deck.util.AttachmentUtil;
 
@@ -26,7 +27,10 @@ public abstract class AttachmentViewHolder extends RecyclerView.ViewHolder {
     }
 
     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));
+        final String downloadUrl = (attachment.getId() == null || cardRemoteId == null)
+                ? attachment.getLocalPath()
+                : AttachmentUtil.getCopyDownloadUrl(account, cardRemoteId, attachment);
+        bind(menuInflater, fragmentManager, cardRemoteId, attachment, onClickListener, mainColor, downloadUrl);
     }
 
     @CallSuper
@@ -34,10 +38,15 @@ public abstract class AttachmentViewHolder extends RecyclerView.ViewHolder {
         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(EAttachmentType.DECK_FILE.equals(attachment.getType())) {
+                menu.findItem(R.id.delete).setOnMenuItemClickListener(item -> {
+                    DeleteAttachmentDialogFragment.newInstance(attachment).show(fragmentManager, DeleteAttachmentDialogFragment.class.getCanonicalName());
+                    return false;
+                });
+                menu.findItem(R.id.delete).setVisible(true);
+            } else {
+                menu.findItem(R.id.delete).setVisible(false);
+            }
             if (attachmentUri == null || attachment.getId() == null || cardRemoteId == null) {
                 menu.findItem(android.R.id.copyUrl).setVisible(false);
             } else {
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 d601f6bbd..16af8bb8f 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
@@ -3,7 +3,6 @@ package it.niedermann.nextcloud.deck.ui.card.attachments;
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
-import android.os.Build;
 import android.view.LayoutInflater;
 import android.view.MenuInflater;
 import android.view.View;
@@ -103,7 +102,7 @@ public class CardAttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHo
                 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) {
+                    if (context instanceof Activity) {
                         String transitionName = context.getString(R.string.transition_attachment_preview, String.valueOf(attachment.getLocalId()));
                         holder.getPreview().setTransitionName(transitionName);
                         context.startActivity(intent, ActivityOptionsCompat.makeSceneTransitionAnimation((Activity) context, holder.getPreview(), transitionName).toBundle());
@@ -115,7 +114,7 @@ public class CardAttachmentAdapter extends RecyclerView.Adapter<AttachmentViewHo
             }
             case VIEW_TYPE_DEFAULT:
             default: {
-                onClickListener = (event) -> openAttachmentInBrowser(context, account.getUrl(), cardRemoteId, attachment.getId());
+                onClickListener = (event) -> openAttachmentInBrowser(account, context, cardRemoteId, attachment);
                 break;
             }
         }
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 9cb3fb778..0cb59c006 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
@@ -45,12 +45,13 @@ import id.zelory.compressor.constraint.SizeConstraint;
 import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.databinding.FragmentCardEditTabAttachmentsBinding;
 import it.niedermann.nextcloud.deck.exceptions.UploadAttachmentFailedException;
 import it.niedermann.nextcloud.deck.model.Attachment;
+import it.niedermann.nextcloud.deck.model.Card;
 import it.niedermann.nextcloud.deck.model.enums.DBStatus;
 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.branding.BrandedSnackbar;
 import it.niedermann.nextcloud.deck.ui.card.EditCardViewModel;
@@ -74,7 +75,6 @@ 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;
@@ -84,11 +84,10 @@ import static com.google.android.material.bottomsheet.BottomSheetBehavior.STATE_
 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;
+import static it.niedermann.nextcloud.deck.util.FilesUtil.copyContentUriToTempFile;
 import static java.net.HttpURLConnection.HTTP_CONFLICT;
 
 public class CardAttachmentsFragment extends BrandedFragment implements AttachmentDeletedListener, AttachmentClickedListener {
@@ -214,15 +213,11 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
 
         if (editViewModel.canEdit()) {
             binding.fab.setOnClickListener(v -> {
-                if (SDK_INT < LOLLIPOP) {
-                    openNativeFilePicker();
-                } else {
-                    binding.bottomNavigation.setSelectedItemId(R.id.gallery);
-                    showGalleryPicker();
-                    mBottomSheetBehaviour.setState(STATE_COLLAPSED);
-                    backPressedCallback.setEnabled(true);
-                    requireActivity().getOnBackPressedDispatcher().addCallback(getViewLifecycleOwner(), backPressedCallback);
-                }
+                binding.bottomNavigation.setSelectedItemId(R.id.gallery);
+                showGalleryPicker();
+                mBottomSheetBehaviour.setState(STATE_COLLAPSED);
+                backPressedCallback.setEnabled(true);
+                requireActivity().getOnBackPressedDispatcher().addCallback(getViewLifecycleOwner(), backPressedCallback);
             });
             binding.fab.show();
             binding.attachmentsList.addOnScrollListener(new RecyclerView.OnScrollListener() {
@@ -239,9 +234,7 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
             binding.emptyContentView.hideDescription();
         }
         @Nullable Context context = requireContext();
-        applyBrand(isBrandingEnabled(context)
-                ? readBrandMainColor(context)
-                : ContextCompat.getColor(context, R.color.defaultBrand));
+        applyBrand(readBrandMainColor(context));
         return binding.getRoot();
     }
 
@@ -309,35 +302,29 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
                 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);
-                }
+//              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);
             }
         }
     }
 
     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());
-        }
+        startActivityForResult(TakePhotoActivity.createIntent(requireContext()), REQUEST_CODE_PICK_CAMERA);
     }
 
     private void openNativeContactPicker() {
@@ -412,28 +399,38 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
         super.onDestroy();
     }
 
-    private void uploadNewAttachmentFromUri(@NonNull Uri sourceUri, String mimeType) throws UploadAttachmentFailedException, IOException {
+    private void uploadNewAttachmentFromUri(@NonNull Uri sourceUri, String mimeType) throws UploadAttachmentFailedException {
         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 originalFile = copyContentUriToTempFile(requireContext(), sourceUri, editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId());
-                if (MimeTypeUtil.isImage(mimeType)) {
-                    JavaCompressor.compress(
-                            (AppCompatActivity) requireActivity(),
-                            originalFile,
-                            (status, file) -> uploadNewAttachmentFromFile(status ? file : originalFile, mimeType),
-                            new ResolutionConstraint(1920, 1920),
-                            new SizeConstraint(1_000_000, 10, 10, 10),
-                            new FormatConstraint(Bitmap.CompressFormat.JPEG),
-                            new QualityConstraint(80)
-                    );
-                } else {
-                    uploadNewAttachmentFromFile(originalFile, mimeType);
-                }
+                DeckLog.verbose("--- found content URL", sourceUri.getPath());
+                // Separate Thread required because picked file might not yet be locally available
+                // https://github.com/stefan-niedermann/nextcloud-deck/issues/814
+                new Thread(() -> {
+                    try {
+                        final File originalFile = copyContentUriToTempFile(requireContext(), sourceUri, editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId());
+                        requireActivity().runOnUiThread(() -> {
+                            if (MimeTypeUtil.isImage(mimeType)) {
+                                JavaCompressor.compress(
+                                        (AppCompatActivity) requireActivity(),
+                                        originalFile,
+                                        (status, file) -> uploadNewAttachmentFromFile(status ? file : originalFile, mimeType),
+                                        new ResolutionConstraint(1920, 1920),
+                                        new SizeConstraint(1_000_000, 10, 10, 10),
+                                        new FormatConstraint(Bitmap.CompressFormat.JPEG),
+                                        new QualityConstraint(80)
+                                );
+                            } else {
+                                uploadNewAttachmentFromFile(originalFile, mimeType);
+                            }
+                        });
+                    } catch (IOException e) {
+                        requireActivity().runOnUiThread(() -> ExceptionDialogFragment.newInstance(e, editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
+                    }
+                }).start();
                 break;
             }
             default: {
@@ -464,22 +461,29 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
         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.addAttachmentToCard(editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId(), a.getMimetype(), fileToUpload, new ResponseCallback<Attachment>() {
+                @Override
+                public void onResponse(Attachment response) {
+                    requireActivity().runOnUiThread(() -> {
                         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 {
-                    editViewModel.getFullCard().getAttachments().remove(a);
-                    editViewModel.getFullCard().getAttachments().add(0, next);
-                    adapter.replaceAttachment(a, next);
+                        editViewModel.getFullCard().getAttachments().add(0, response);
+                        adapter.replaceAttachment(a, response);
+                    });
+                }
+
+                @Override
+                public void onError(Throwable throwable) {
+                    requireActivity().runOnUiThread(() -> {
+                        if (throwable instanceof NextcloudHttpRequestFailedException && ((NextcloudHttpRequestFailedException) throwable).getStatusCode() == HTTP_CONFLICT) {
+                            ResponseCallback.super.onError(throwable);
+                            // 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", throwable), editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+                        }
+                    });
                 }
             });
         }
@@ -522,10 +526,18 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
         adapter.removeAttachment(attachment);
         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());
+            editViewModel.deleteAttachmentOfCard(editViewModel.getAccount().getId(), editViewModel.getFullCard().getLocalId(), attachment.getLocalId(), new ResponseCallback<Void>() {
+                @Override
+                public void onResponse(Void response) {
+                    DeckLog.info("Successfully delete", Attachment.class.getSimpleName(), attachment.getFilename(), "from", Card.class.getSimpleName(), editViewModel.getFullCard().getCard().getTitle());
+                }
+
+                @Override
+                public void onError(Throwable throwable) {
+                    if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                        ResponseCallback.super.onError(throwable);
+                        requireActivity().runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, editViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
+                    }
                 }
             });
         }
@@ -539,7 +551,6 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
     @Override
     public void applyBrand(int mainColor) {
         applyBrandToFAB(mainColor, binding.fab);
-        adapter.applyBrand(mainColor);
         @ColorInt final int finalMainColor = DeckColorUtil.contrastRatioIsSufficient(mainColor, primaryColor)
                 ? mainColor
                 : accentColor;
@@ -555,6 +566,13 @@ public class CardAttachmentsFragment extends BrandedFragment implements Attachme
         );
         binding.bottomNavigation.setItemIconTintList(list);
         binding.bottomNavigation.setItemTextColor(list);
+
+        // applyBrand() is also called onStart
+        // adapter might be null at this point
+        // https://github.com/stefan-niedermann/nextcloud-deck/issues/782
+        if (adapter != null) {
+            adapter.applyBrand(mainColor);
+        }
     }
 
     public static Fragment newInstance() {
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 2b5358eb9..b41a4e9d1 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
@@ -40,7 +40,7 @@ public class DefaultAttachmentViewHolder extends AttachmentViewHolder {
     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()));
+        itemView.setOnClickListener((event) -> openAttachmentInBrowser(account, itemView.getContext(), cardRemoteId, attachment));
         binding.filename.setText(attachment.getBasename());
         binding.filesize.setText(Formatter.formatFileSize(binding.filesize.getContext(), attachment.getFilesize()));
         if (attachment.getLastModifiedLocal() != null) {
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 3c95da1b7..b93b3d025 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
@@ -37,10 +37,13 @@ public class ImageAttachmentViewHolder extends AttachmentViewHolder {
     }
 
     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));
+        final String downloadUrl = (attachment.getId() == null || cardRemoteId == null)
+                ? attachment.getLocalPath()
+                : AttachmentUtil.getCopyDownloadUrl(account, cardRemoteId, attachment);
+        super.bind(menuInflater, fragmentManager, cardRemoteId, attachment, onClickListener, mainColor, downloadUrl);
 
         getPreview().post(() -> {
-            @Nullable final String uri = AttachmentUtil.getThumbnailUrl(account.getServerDeckVersionAsObject(), account.getUrl(), cardRemoteId, attachment, getPreview().getWidth());
+            @Nullable final String uri = AttachmentUtil.getThumbnailUrl(account, cardRemoteId, attachment, getPreview().getWidth());
             Glide.with(getPreview().getContext())
                     .load(uri)
                     .placeholder(R.drawable.ic_image_grey600_24dp)
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsAdapter.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsAdapter.java
index 169a37c79..4fde5a4e1 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsAdapter.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/card/comments/CardCommentsAdapter.java
@@ -11,7 +11,9 @@ import androidx.recyclerview.widget.RecyclerView;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
+import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.databinding.ItemCommentBinding;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.ocs.comment.full.FullDeckComment;
@@ -21,7 +23,7 @@ import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMai
 
 public class CardCommentsAdapter extends RecyclerView.Adapter<ItemCommentViewHolder> {
 
-    private int mainColor;
+    private final int mainColor;
     @NonNull
     private final List<FullDeckComment> comments = new ArrayList<>();
     @NonNull
@@ -34,13 +36,16 @@ public class CardCommentsAdapter extends RecyclerView.Adapter<ItemCommentViewHol
     private final CommentSelectAsReplyListener selectAsReplyListener;
     @NonNull
     private final FragmentManager fragmentManager;
+    @NonNull
+    private final CommentEditedListener editListener;
 
-    CardCommentsAdapter(@NonNull Context context, @NonNull Account account, @NonNull MenuInflater menuInflater, @NonNull CommentDeletedListener deletedListener, @NonNull CommentSelectAsReplyListener selectAsReplyListener, @NonNull FragmentManager fragmentManager) {
+    CardCommentsAdapter(@NonNull Context context, @NonNull Account account, @NonNull MenuInflater menuInflater, @NonNull CommentDeletedListener deletedListener, @NonNull CommentSelectAsReplyListener selectAsReplyListener, @NonNull FragmentManager fragmentManager, CommentEditedListener editListener) {
         this.account = account;
         this.menuInflater = menuInflater;
         this.deletedListener = deletedListener;
         this.selectAsReplyListener = selectAsReplyListener;
         this.fragmentManager = fragmentManager;
+        this.editListener = editListener;
         this.mainColor = getSecondaryForegroundColorDependingOnTheme(context, readBrandMainColor(context));
         setHasStableIds(true);
     }
@@ -58,7 +63,19 @@ public class CardCommentsAdapter extends RecyclerView.Adapter<ItemCommentViewHol
 
     @Override
     public void onBindViewHolder(@NonNull ItemCommentViewHolder holder, int position) {
-        holder.bind(comments.get(position), account, mainColor, menuInflater, deletedListener, selectAsReplyListener, fragmentManager);
+        final FullDeckComment comment = comments.get(position);
+        holder.bind(comment, account, mainColor, menuInflater, deletedListener, selectAsReplyListener, fragmentManager, (changedText) -> {
+            if (!Objects.equals(changedText, comment.getComment().getMessage())) {
+                DeckLog.info("Toggled checkbox in comment with localId", comment.getLocalId());
+                this.editListener.onCommentEdited(comment.getLocalId(), changedText.toString());
+            }
+        });
+    }
+
+    @Override
+    public void onViewRecycled(@NonNull ItemCommentViewHolder holder) {
+        super.onViewRecycled(holder);
+        holder.unbind();
     }
 
     @SuppressWarnings("WeakerAccess")
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 3fd536aa6..2f538f9bb 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
@@ -17,24 +17,24 @@ import androidx.lifecycle.ViewModelProvider;
 
 import java.time.Instant;
 
+import it.niedermann.android.util.DimensionUtil;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.databinding.FragmentCardEditTabCommentsBinding;
 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 it.niedermann.nextcloud.deck.util.ViewUtil;
 
 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;
 
 public class CardCommentsFragment extends BrandedFragment implements CommentEditedListener, CommentDeletedListener, CommentSelectAsReplyListener {
 
@@ -70,17 +70,18 @@ public class CardCommentsFragment extends BrandedFragment implements CommentEdit
 
         commentsViewModel = new ViewModelProvider(this).get(CommentsViewModel.class);
 
-        adapter = new CardCommentsAdapter(requireContext(), mainViewModel.getAccount(), requireActivity().getMenuInflater(), this, this, getChildFragmentManager());
+        adapter = new CardCommentsAdapter(requireContext(), mainViewModel.getAccount(), requireActivity().getMenuInflater(), this, this, getChildFragmentManager(), this);
         binding.comments.setAdapter(adapter);
-
         binding.replyCommentCancelButton.setOnClickListener((v) -> commentsViewModel.setReplyToComment(null));
+        ViewUtil.addAvatar(binding.avatar, mainViewModel.getAccount().getUrl(), mainViewModel.getAccount().getUserName(), DimensionUtil.INSTANCE.dpToPx(binding.avatar.getContext(), R.dimen.icon_size_details), R.drawable.ic_person_grey600_24dp);
+
         commentsViewModel.getReplyToComment().observe(getViewLifecycleOwner(), (comment) -> {
             if (comment == null) {
                 binding.replyComment.setVisibility(GONE);
             } else {
-                binding.replyCommentText.setText(comment.getComment().getMessage());
+                binding.replyCommentText.setMarkdownString(comment.getComment().getMessage());
                 binding.replyComment.setVisibility(VISIBLE);
-                setupMentions(mainViewModel.getAccount(), comment.getComment().getMentions(), binding.replyCommentText);
+//                setupMentions(mainViewModel.getAccount(), comment.getComment().getMentions(), binding.replyCommentText);
             }
         });
         commentsViewModel.getFullCommentsForLocalCardId(mainViewModel.getFullCard().getLocalId()).observe(getViewLifecycleOwner(),
@@ -140,10 +141,18 @@ public class CardCommentsFragment extends BrandedFragment implements CommentEdit
 
     @Override
     public void onCommentDeleted(Long 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());
+        commentsViewModel.deleteComment(mainViewModel.getAccount().getId(), mainViewModel.getFullCard().getLocalId(), localId, new ResponseCallback<Void>() {
+            @Override
+            public void onResponse(Void response) {
+                DeckLog.info("Successfully deleted comment with localId", localId);
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                if (!SyncManager.ignoreExceptionOnVoidError(throwable)) {
+                    ResponseCallback.super.onError(throwable);
+                    requireActivity().runOnUiThread(() -> ExceptionDialogFragment.newInstance(throwable, mainViewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName()));
+                }
             }
         });
     }
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 dada94d5b..7e29769cd 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
@@ -9,10 +9,12 @@ import androidx.lifecycle.MutableLiveData;
 
 import java.util.List;
 
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 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 static androidx.lifecycle.Transformations.distinctUntilChanged;
 
 @SuppressWarnings("WeakerAccess")
 public class CommentsViewModel extends AndroidViewModel {
@@ -35,7 +37,7 @@ public class CommentsViewModel extends AndroidViewModel {
     }
 
     public LiveData<List<FullDeckComment>> getFullCommentsForLocalCardId(long localCardId) {
-        return syncManager.getFullCommentsForLocalCardId(localCardId);
+        return distinctUntilChanged(syncManager.getFullCommentsForLocalCardId(localCardId));
     }
 
     public void addCommentToCard(long accountId, long cardId, @NonNull DeckComment comment) {
@@ -46,7 +48,7 @@ public class CommentsViewModel extends AndroidViewModel {
         syncManager.updateComment(accountId, localCardId, localCommentId, comment);
     }
 
-    public WrappedLiveData<Void> deleteComment(long accountId, long localCardId, long localCommentId) {
-        return syncManager.deleteComment(accountId, localCardId, localCommentId);
+    public void deleteComment(long accountId, long localCardId, long localCommentId, @NonNull ResponseCallback<Void> callback) {
+        syncManager.deleteComment(accountId, localCardId, localCommentId, callback);
     }
 }
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 3e540c95e..c85f9d7b5 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
@@ -1,5 +1,6 @@
 package it.niedermann.nextcloud.deck.ui.card.comments;
 
+import android.text.method.LinkMovementMethod;
 import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
@@ -14,6 +15,9 @@ import androidx.recyclerview.widget.RecyclerView;
 import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.time.format.FormatStyle;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Consumer;
 
 import it.niedermann.android.util.ClipboardUtil;
 import it.niedermann.android.util.DimensionUtil;
@@ -21,12 +25,11 @@ 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.Mention;
 import it.niedermann.nextcloud.deck.model.ocs.comment.full.FullDeckComment;
 import it.niedermann.nextcloud.deck.util.DateUtil;
 import it.niedermann.nextcloud.deck.util.ViewUtil;
 
-import static it.niedermann.nextcloud.deck.util.ViewUtil.setupMentions;
-
 public class ItemCommentViewHolder extends RecyclerView.ViewHolder {
     private final ItemCommentBinding binding;
     private final DateTimeFormatter dateFormatter = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM);
@@ -35,15 +38,22 @@ public class ItemCommentViewHolder extends RecyclerView.ViewHolder {
     public ItemCommentViewHolder(ItemCommentBinding binding) {
         super(binding.getRoot());
         this.binding = binding;
+        this.binding.message.setMovementMethod(LinkMovementMethod.getInstance());
     }
 
-    public void bind(@NonNull FullDeckComment comment, @NonNull Account account, @ColorInt int mainColor, @NonNull MenuInflater inflater, @NonNull CommentDeletedListener deletedListener, @NonNull CommentSelectAsReplyListener selectAsReplyListener, @NonNull FragmentManager fragmentManager) {
+    public void bind(@NonNull FullDeckComment comment, @NonNull Account account, @ColorInt int mainColor, @NonNull MenuInflater inflater, @NonNull CommentDeletedListener deletedListener, @NonNull CommentSelectAsReplyListener selectAsReplyListener, @NonNull FragmentManager fragmentManager, @NonNull Consumer<CharSequence> editListener) {
         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);
+        final Map<String, String> mentions = new HashMap<>(comment.getComment().getMentions().size());
+        for (Mention mention : comment.getComment().getMentions()) {
+            mentions.put(mention.getMentionId(), mention.getMentionDisplayName());
+        }
         binding.message.setText(comment.getComment().getMessage());
+        binding.message.setMarkdownString(comment.getComment().getMessage(), mentions);
+        binding.message.setMarkdownStringChangedListener(editListener);
         binding.actorDisplayName.setText(comment.getComment().getActorDisplayName());
         binding.creationDateTime.setText(DateUtil.getRelativeDateTimeString(binding.creationDateTime.getContext(), comment.getComment().getCreationDateTime().toEpochMilli()));
-        itemView.setOnClickListener(View::showContextMenu);
 
+        itemView.setOnClickListener(View::showContextMenu);
         itemView.setOnCreateContextMenuListener((menu, v, menuInfo) -> {
             inflater.inflate(R.menu.comment_menu, menu);
             menu.findItem(android.R.id.copy).setOnMenuItemClickListener(item -> ClipboardUtil.INSTANCE.copyToClipboard(itemView.getContext(), comment.getComment().getMessage()));
@@ -72,12 +82,10 @@ public class ItemCommentViewHolder extends RecyclerView.ViewHolder {
             }
         });
 
+        TooltipCompat.setTooltipText(binding.creationDateTime, comment.getComment().getCreationDateTime().atZone(ZoneId.systemDefault()).format(dateFormatter));
         DrawableCompat.setTint(binding.notSyncedYet.getDrawable(), mainColor);
         binding.notSyncedYet.setVisibility(DBStatus.LOCAL_EDITED.equals(comment.getStatusEnum()) ? View.VISIBLE : View.GONE);
 
-        TooltipCompat.setTooltipText(binding.creationDateTime, comment.getComment().getCreationDateTime().atZone(ZoneId.systemDefault()).format(dateFormatter));
-        setupMentions(account, comment.getComment().getMentions(), binding.message);
-
         if (comment.getParent() == null) {
             binding.parentContainer.setVisibility(View.GONE);
         } else {
@@ -95,4 +103,9 @@ public class ItemCommentViewHolder extends RecyclerView.ViewHolder {
             });
         }
     }
+
+    public void unbind() {
+        binding.message.setText("");
+        binding.message.setMarkdownStringChangedListener(null);
+    }
 }
\ No newline at end of file
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
index 5251291c8..8fa24988d 100644
--- 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
@@ -1,12 +1,14 @@
 package it.niedermann.nextcloud.deck.ui.card.comments.util;
 
 
+import androidx.annotation.Nullable;
 import androidx.core.util.Pair;
 
 public class CommentsUtil {
 
+    @Nullable
     public static Pair<String, Integer> getUserNameForMentionProposal(String text, int cursorPosition) {
-        Pair result = null;
+        Pair<String, Integer> result = null;
 
         if (text != null) {
             // find start of relevant substring
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 2c697de08..8376a6817 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
@@ -4,9 +4,8 @@ import android.content.Context;
 import android.content.res.ColorStateList;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
-import android.text.Editable;
 import android.text.TextUtils;
-import android.text.TextWatcher;
+import android.text.method.LinkMovementMethod;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -19,6 +18,7 @@ import androidx.core.content.ContextCompat;
 import androidx.core.graphics.ColorUtils;
 import androidx.core.graphics.drawable.DrawableCompat;
 import androidx.fragment.app.Fragment;
+import androidx.lifecycle.Observer;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.recyclerview.widget.GridLayoutManager;
 
@@ -28,8 +28,6 @@ import com.wdullaer.materialdatetimepicker.date.DatePickerDialog;
 import com.wdullaer.materialdatetimepicker.date.DatePickerDialog.OnDateSetListener;
 import com.wdullaer.materialdatetimepicker.time.TimePickerDialog;
 import com.wdullaer.materialdatetimepicker.time.TimePickerDialog.OnTimeSetListener;
-import com.yydcdut.markdown.MarkdownProcessor;
-import com.yydcdut.markdown.syntax.edit.EditFactory;
 
 import java.time.Instant;
 import java.time.LocalDate;
@@ -43,10 +41,11 @@ 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.api.ResponseCallback;
 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.adapters.db.util.WrappedLiveData;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedDatePickerDialog;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedFragment;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedSnackbar;
@@ -57,11 +56,9 @@ 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.MarkDownUtil;
 
 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;
 
 public class CardDetailsFragment extends BrandedFragment implements OnDateSetListener, OnTimeSetListener, CardAssigneeListener {
@@ -72,6 +69,7 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
     private final DateTimeFormatter dateFormatter = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM);
     private final DateTimeFormatter timeFormatter = DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT);
     private AppCompatActivity activity;
+    boolean editorActive = true;
 
     @Override
     public void onAttach(@NonNull Context context) {
@@ -110,7 +108,6 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
         setupDueDate();
         setupDescription();
         setupProjects();
-        binding.description.setText(viewModel.getFullCard().getCard().getDescription());
 
         return binding.getRoot();
     }
@@ -137,35 +134,48 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
         applyBrandToEditText(mainColor, binding.dueDateDate);
         applyBrandToEditText(mainColor, binding.dueDateTime);
         applyBrandToEditText(mainColor, binding.people);
-        applyBrandToEditText(mainColor, binding.description);
+        binding.descriptionEditor.setSearchColor(mainColor);
+        binding.descriptionViewer.setSearchColor(mainColor);
     }
 
     private void setupDescription() {
         if (viewModel.canEdit()) {
-            MarkdownProcessor markdownProcessor = new MarkdownProcessor(requireContext());
-            markdownProcessor.config(MarkDownUtil.getMarkDownConfiguration(binding.description.getContext()).build());
-            markdownProcessor.factory(EditFactory.create());
-            markdownProcessor.live(binding.description);
-            binding.description.addTextChangedListener(new TextWatcher() {
-                @Override
-                public void onTextChanged(CharSequence s, int start, int before, int count) {
-                    if (viewModel.getFullCard() != null) {
-                        viewModel.getFullCard().getCard().setDescription(binding.description.getText().toString());
-                    }
-                }
-
-                @Override
-                public void beforeTextChanged(CharSequence s, int start, int count, int after) {
-                    // Nothing to do
+            binding.descriptionViewer.setMovementMethod(LinkMovementMethod.getInstance());
+            binding.descriptionBar.setOnClickListener((v) -> binding.descriptionEditor.requestFocus());
+            binding.descriptionToggle.setOnClickListener((v) -> {
+                editorActive = !editorActive;
+                if (editorActive) {
+                    binding.descriptionEditor.setMarkdownString(viewModel.getFullCard().getCard().getDescription());
+                    binding.descriptionBar.setOnClickListener((view) -> binding.descriptionEditor.requestFocus());
+                    binding.descriptionEditor.setVisibility(VISIBLE);
+                    binding.descriptionViewer.setVisibility(GONE);
+                    binding.descriptionToggle.setImageResource(R.drawable.ic_baseline_eye_24);
+                } else {
+                    binding.descriptionViewer.setMarkdownString(viewModel.getFullCard().getCard().getDescription());
+                    binding.descriptionBar.setOnClickListener(null);
+                    binding.descriptionEditor.setVisibility(GONE);
+                    binding.descriptionViewer.setVisibility(VISIBLE);
+                    binding.descriptionToggle.setImageResource(R.drawable.ic_edit_grey600_24dp);
                 }
+            });
+            binding.descriptionEditor.setMarkdownString(viewModel.getFullCard().getCard().getDescription());
+            final Observer<CharSequence> descriptionObserver = (description) -> {
 
-                @Override
-                public void afterTextChanged(Editable s) {
-                    // Nothing to do
+                if (viewModel.getFullCard() != null) {
+                    viewModel.getFullCard().getCard().setDescription(description == null ? "" : description.toString());
+                } else {
+                    ExceptionDialogFragment.newInstance(new IllegalStateException(FullCard.class.getSimpleName() + " was empty when trying to setup description"), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
                 }
-            });
+                binding.descriptionToggle.setVisibility(TextUtils.isEmpty(description) ? GONE : VISIBLE);
+            };
+            binding.descriptionEditor.getMarkdownString().observe(getViewLifecycleOwner(), descriptionObserver);
+            binding.descriptionViewer.getMarkdownString().observe(getViewLifecycleOwner(), descriptionObserver);
         } else {
-            binding.description.setEnabled(false);
+            binding.descriptionEditor.setEnabled(false);
+            binding.descriptionEditor.setVisibility(VISIBLE);
+            binding.descriptionViewer.setEnabled(false);
+            binding.descriptionViewer.setVisibility(GONE);
+            binding.descriptionViewer.setMarkdownString(viewModel.getFullCard().getCard().getDescription());
         }
     }
 
@@ -233,18 +243,23 @@ public class CardDetailsFragment extends BrandedFragment implements OnDateSetLis
                     newLabel.setBoardId(boardId);
                     newLabel.setTitle(((LabelAutoCompleteAdapter) binding.labels.getAdapter()).getLastFilterText());
                     newLabel.setLocalId(null);
-                    WrappedLiveData<Label> createLabelLiveData = viewModel.createLabel(accountId, newLabel, boardId);
-                    observeOnce(createLabelLiveData, CardDetailsFragment.this, createdLabel -> {
-                        if (createLabelLiveData.hasError()) {
-                            DeckLog.logError(createLabelLiveData.getError());
-                            BrandedSnackbar.make(requireView(), getString(R.string.error_create_label, newLabel.getTitle()), Snackbar.LENGTH_LONG)
-                                    .setAction(R.string.simple_more, v -> ExceptionDialogFragment.newInstance(createLabelLiveData.getError(), viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName())).show();
-                        } else {
-                            newLabel.setLocalId(createdLabel.getLocalId());
-                            ((LabelAutoCompleteAdapter) binding.labels.getAdapter()).exclude(createdLabel);
-                            viewModel.getFullCard().getLabels().add(createdLabel);
-                            binding.labelsGroup.addView(createChipFromLabel(newLabel));
-                            binding.labelsGroup.setVisibility(VISIBLE);
+                    viewModel.createLabel(accountId, newLabel, boardId, new ResponseCallback<Label>() {
+                        @Override
+                        public void onResponse(Label response) {
+                            requireActivity().runOnUiThread(() -> {
+                                newLabel.setLocalId(response.getLocalId());
+                                ((LabelAutoCompleteAdapter) binding.labels.getAdapter()).exclude(response);
+                                viewModel.getFullCard().getLabels().add(response);
+                                binding.labelsGroup.addView(createChipFromLabel(newLabel));
+                                binding.labelsGroup.setVisibility(VISIBLE);
+                            });
+                        }
+
+                        @Override
+                        public void onError(Throwable throwable) {
+                            ResponseCallback.super.onError(throwable);
+                            requireActivity().runOnUiThread(() -> BrandedSnackbar.make(requireView(), getString(R.string.error_create_label, newLabel.getTitle()), Snackbar.LENGTH_LONG)
+                                    .setAction(R.string.simple_more, v -> ExceptionDialogFragment.newInstance(throwable, viewModel.getAccount()).show(getChildFragmentManager(), ExceptionDialogFragment.class.getSimpleName())).show());
                         }
                     });
                 } else {
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
index 272945e45..c398d9814 100644
--- 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
@@ -86,14 +86,14 @@ public class CardProjectResourceViewHolder extends RecyclerView.ViewHolder {
                     break;
                 }
                 default: {
-                    DeckLog.info("Unknown resource type for " + resource.getName() + ": " + resource.getType());
+                    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");
+            DeckLog.warn("Resource type for", resource.getName(), "is null");
             binding.type.setVisibility(GONE);
         }
     }
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 6bfd82b13..b87cee5f9 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
@@ -2,6 +2,7 @@ package it.niedermann.nextcloud.deck.ui.exception.tips;
 
 import android.content.Context;
 import android.content.Intent;
+import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.Build.VERSION;
 import android.os.Build.VERSION_CODES;
@@ -16,6 +17,7 @@ import androidx.annotation.StringRes;
 import androidx.core.util.Consumer;
 import androidx.recyclerview.widget.RecyclerView;
 
+import com.nextcloud.android.sso.Constants;
 import com.nextcloud.android.sso.exceptions.NextcloudApiNotRespondingException;
 import com.nextcloud.android.sso.exceptions.NextcloudFilesAppNotSupportedException;
 import com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException;
@@ -39,14 +41,15 @@ import static it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment.
 
 public class TipsAdapter extends RecyclerView.Adapter<TipsViewHolder> {
 
+    private static final String[] APPS = new String[]{Constants.PACKAGE_NAME_PROD, Constants.PACKAGE_NAME_DEV};
     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;
+    private final Consumer<Intent> actionButtonClickedListener;
     @NonNull
-    private List<TipsModel> tips = new LinkedList<>();
+    private final List<TipsModel> tips = new LinkedList<>();
 
     public TipsAdapter(@NonNull Consumer<Intent> actionButtonClickedListener) {
         this.actionButtonClickedListener = actionButtonClickedListener;
@@ -113,6 +116,19 @@ public class TipsAdapter extends RecyclerView.Adapter<TipsViewHolder> {
             }
         } else if (throwable instanceof UploadAttachmentFailedException) {
             add(R.string.error_dialog_attachment_upload_failed);
+        } else if (throwable instanceof ClassNotFoundException) {
+            final Throwable cause = ((ClassNotFoundException) throwable).getCause();
+            if (cause != null) {
+                final String message = cause.getMessage();
+                if (message != null && message.toLowerCase().contains("certificate")) {
+                    final Intent filesOpenIntent = getOpenFilesIntent(context);
+                    if (filesOpenIntent == null) {
+                        add(R.string.error_dialog_certificate);
+                    } else {
+                        add(R.string.error_dialog_certificate, filesOpenIntent);
+                    }
+                }
+            }
         } else if (throwable instanceof DeckException) {
             switch (((DeckException) throwable).getHint()) {
                 case CAPABILITIES_VERSION_NOT_PARSABLE:
@@ -142,7 +158,7 @@ public class TipsAdapter extends RecyclerView.Adapter<TipsViewHolder> {
             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")) {
+            if (throwable.getMessage() != null && throwable.getMessage().toLowerCase().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);
@@ -159,4 +175,18 @@ public class TipsAdapter extends RecyclerView.Adapter<TipsViewHolder> {
         tips.add(new TipsModel(text, primaryAction));
         notifyItemInserted(tips.size());
     }
+
+    @Nullable
+    private static Intent getOpenFilesIntent(@NonNull Context context) {
+        final PackageManager pm = context.getPackageManager();
+        for (String app : APPS) {
+            try {
+                pm.getPackageInfo(app, PackageManager.GET_ACTIVITIES);
+                return pm.getLaunchIntentForPackage(app)
+                        .putExtra(INTENT_EXTRA_BUTTON_TEXT, R.string.error_action_open_nextcloud_app);
+            } catch (PackageManager.NameNotFoundException ignored) {
+            }
+        }
+        return null;
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsModel.java
index 00bfa6b15..749579812 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsModel.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsModel.java
@@ -8,10 +8,9 @@ import androidx.annotation.StringRes;
 @SuppressWarnings("WeakerAccess")
 public class TipsModel {
     @StringRes
-    private int text;
+    private final int text;
     @Nullable
-    private
-    Intent actionIntent;
+    private final Intent actionIntent;
 
     TipsModel(@StringRes int text, @Nullable Intent actionIntent) {
         this.text = text;
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsViewHolder.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsViewHolder.java
index 622a32e3b..7d254459e 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsViewHolder.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/exception/tips/TipsViewHolder.java
@@ -20,7 +20,7 @@ public class TipsViewHolder extends RecyclerView.ViewHolder {
         binding = ItemTipBinding.bind(itemView);
     }
 
-    public void bind(TipsModel tip, Consumer<Intent> actionButtonClickedListener) {
+    public void bind(@NonNull TipsModel tip, @NonNull Consumer<Intent> actionButtonClickedListener) {
         binding.tip.setText(tip.getText());
         final Intent actionIntent = tip.getActionIntent();
         if (actionIntent != null && actionIntent.hasExtra(INTENT_EXTRA_BUTTON_TEXT)) {
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 6aa03b811..647dfd651 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
@@ -11,8 +11,6 @@ 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;
-import androidx.lifecycle.Lifecycle;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.viewpager2.adapter.FragmentStateAdapter;
@@ -49,14 +47,14 @@ public class FilterDialogFragment extends BrandedDialogFragment {
 
         indicator = ContextCompat.getDrawable(requireContext(), R.drawable.circle_grey600_8dp);
         assert indicator != null;
-        indicator.setColorFilter(getResources().getColor(R.color.defaultBrand), PorterDuff.Mode.SRC_ATOP);
+        indicator.setColorFilter(ContextCompat.getColor(getContext(), R.color.defaultBrand), PorterDuff.Mode.SRC_ATOP);
 
         filterViewModel = new ViewModelProvider(requireActivity()).get(FilterViewModel.class);
 
         final AlertDialog.Builder dialogBuilder = new BrandedAlertDialogBuilder(requireContext());
 
         binding = DialogFilterBinding.inflate(requireActivity().getLayoutInflater());
-        binding.viewPager.setAdapter(new TabsPagerAdapter(getChildFragmentManager(), getLifecycle()));
+        binding.viewPager.setAdapter(new TabsPagerAdapter(this));
         binding.viewPager.setOffscreenPageLimit(tabTitles.length);
 
         LiveData<FilterInformation> filterInformationDraft = filterViewModel.getFilterInformationDraft();
@@ -114,8 +112,8 @@ public class FilterDialogFragment extends BrandedDialogFragment {
 
     private static class TabsPagerAdapter extends FragmentStateAdapter {
 
-        TabsPagerAdapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle) {
-            super(fragmentManager, lifecycle);
+        TabsPagerAdapter(final Fragment f) {
+            super(f);
         }
 
         @NonNull
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 8aa45e39a..aec258d59 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
@@ -1,8 +1,11 @@
 package it.niedermann.nextcloud.deck.ui.manageaccounts;
 
+import android.content.Context;
+import android.content.Intent;
 import android.os.Bundle;
 import android.util.Log;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.lifecycle.ViewModelProvider;
@@ -51,7 +54,6 @@ public class ManageAccountsActivity extends AppCompatActivity {
             viewModel.readAccounts().observe(this, (localAccounts -> {
                 if (localAccounts.size() == 0) {
                     Log.i(TAG, "No accounts, finishing " + ManageAccountsActivity.class.getSimpleName());
-                    setResult(AppCompatActivity.RESULT_FIRST_USER);
                     finish();
                 } else {
                     adapter.setAccounts(localAccounts);
@@ -64,4 +66,8 @@ public class ManageAccountsActivity extends AppCompatActivity {
     public void onBackPressed() {
         onSupportNavigateUp();
     }
+    
+    public static Intent createIntent(@NonNull Context context) {
+        return new Intent(context, ManageAccountsActivity.class);
+    }
 }
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
index 66e9d3850..da89f3588 100644
--- 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
@@ -13,7 +13,7 @@ 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;
+import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentAccount;
 
 @SuppressWarnings("WeakerAccess")
 public class ManageAccountsViewModel extends AndroidViewModel {
@@ -36,7 +36,7 @@ public class ManageAccountsViewModel extends AndroidViewModel {
     public void setNewAccount(@NonNull Account account) {
         SingleAccountHelper.setCurrentAccount(getApplication(), account.getName());
         syncManager = new SyncManager(getApplication());
-        saveCurrentAccountId(getApplication(), account.getId());
+        saveCurrentAccount(getApplication(), account);
     }
 
     public void deleteAccount(long 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
index 2b7eb52fe..442f2c6eb 100644
--- 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
@@ -32,10 +32,12 @@ public class MoveCardDialogFragment extends BrandedDialogFragment implements Pic
     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 static final String KEY_ORIGIN_CARD_HAS_ATTACHMENTS_OR_COMMENTS = "card_has_attachments_or_comments";
     private Long originAccountId;
     private Long originBoardLocalId;
     private String originCardTitle;
     private Long originCardLocalId;
+    private boolean originCardHasAttachmentsOrComments;
 
     private DialogMoveCardBinding binding;
     private PickStackViewModel viewModel;
@@ -69,6 +71,7 @@ public class MoveCardDialogFragment extends BrandedDialogFragment implements Pic
         if (originBoardLocalId < 0) {
             throw new IllegalArgumentException("Missing " + KEY_ORIGIN_BOARD_LOCAL_ID);
         }
+        originCardHasAttachmentsOrComments = args.getBoolean(KEY_ORIGIN_CARD_HAS_ATTACHMENTS_OR_COMMENTS, false);
         originCardTitle = args.getString(KEY_ORIGIN_CARD_TITLE);
     }
 
@@ -78,7 +81,7 @@ public class MoveCardDialogFragment extends BrandedDialogFragment implements Pic
         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());
+            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();
         });
@@ -104,7 +107,7 @@ public class MoveCardDialogFragment extends BrandedDialogFragment implements Pic
             binding.moveWarning.setVisibility(GONE);
         } else {
             binding.submit.setEnabled(true);
-            binding.moveWarning.setVisibility(board.getLocalId().equals(originBoardLocalId) ? GONE : VISIBLE);
+            binding.moveWarning.setVisibility(originCardHasAttachmentsOrComments && !board.getLocalId().equals(originBoardLocalId) ? VISIBLE : GONE);
         }
     }
 
@@ -115,13 +118,14 @@ public class MoveCardDialogFragment extends BrandedDialogFragment implements Pic
         binding.submit.setTextColor(mainColorStateList);
     }
 
-    public static DialogFragment newInstance(long originAccountId, long originBoardLocalId, String originCardTitle, Long originCardLocalId) {
+    public static DialogFragment newInstance(long originAccountId, long originBoardLocalId, String originCardTitle, Long originCardLocalId, boolean hasAttachmentsOrComments) {
         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);
+        args.putBoolean(KEY_ORIGIN_CARD_HAS_ATTACHMENTS_OR_COMMENTS, hasAttachmentsOrComments);
         dialogFragment.setArguments(args);
         return dialogFragment;
     }
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
index d65971cf4..6408f6b64 100644
--- 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
@@ -1,7 +1,6 @@
 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;
@@ -142,7 +141,7 @@ public class PickStackFragment extends Fragment {
             if (hasAccounts) {
                 return viewModel.readAccounts();
             } else {
-                startActivityForResult(new Intent(requireActivity(), ImportAccountActivity.class), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
+                startActivityForResult(ImportAccountActivity.createIntent(requireContext()), ImportAccountActivity.REQUEST_CODE_IMPORT_ACCOUNT);
                 return null;
             }
         }).observe(getViewLifecycleOwner(), (List<Account> accounts) -> {
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 f537c9fb4..9534b51b4 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
@@ -50,7 +50,7 @@ public class AccountAdapter extends AbstractAdapter<Account> {
             }
 
             Glide.with(getContext())
-                    .load(new SingleSignOnUrl(item.getName(), item.getAvatarUrl(DimensionUtil.INSTANCE.dpToPx(binding.avatar.getContext(), R.dimen.icon_size_details))))
+                    .load(new SingleSignOnUrl(item.getName(), item.getAvatarUrl(DimensionUtil.INSTANCE.dpToPx(binding.avatar.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/preparecreate/PrepareCreateActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/preparecreate/PrepareCreateActivity.java
index 18317e078..53e25a0d9 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
@@ -1,9 +1,7 @@
 package it.niedermann.nextcloud.deck.ui.preparecreate;
 
-import android.content.ClipData;
 import android.content.Intent;
 import android.os.Bundle;
-import android.text.TextUtils;
 
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.ActionBar;
@@ -13,7 +11,7 @@ import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.ui.PickStackActivity;
 import it.niedermann.nextcloud.deck.ui.card.EditActivity;
 
-import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentAccountId;
+import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentAccount;
 import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentBoardId;
 import static it.niedermann.nextcloud.deck.DeckApplication.saveCurrentStackId;
 
@@ -30,14 +28,16 @@ public class PrepareCreateActivity extends PickStackActivity {
 
     @Override
     protected void onSubmit(Account account, long boardId, long stackId) {
-        final String receivedClipData = getReceivedClipData(getIntent());
-        if (receivedClipData == null) {
+        final Intent intent = getIntent();
+        if (intent == null) {
             startActivity(EditActivity.createNewCardIntent(this, account, boardId, stackId));
         } else {
-            startActivity(EditActivity.createNewCardIntent(this, account, boardId, stackId, receivedClipData));
+            startActivity(EditActivity.createNewCardIntent(this, account, boardId, stackId,
+                    intent.getStringExtra(Intent.EXTRA_TITLE),
+                    intent.getStringExtra(Intent.EXTRA_TEXT)));
         }
 
-        saveCurrentAccountId(this, account.getId());
+        saveCurrentAccount(this, account);
         saveCurrentBoardId(this, account.getId(), boardId);
         saveCurrentStackId(this, account.getId(), boardId, stackId);
         applyBrand(account.getColor());
@@ -49,25 +49,4 @@ public class PrepareCreateActivity extends PickStackActivity {
     protected boolean showBoardsWithoutEditPermission() {
         return false;
     }
-
-    @Nullable
-    private static String getReceivedClipData(@Nullable Intent intent) {
-        if (intent == null) {
-            return null;
-        }
-        final ClipData clipData = intent.getClipData();
-        if (clipData == null) {
-            return null;
-        }
-        final int itemCount = clipData.getItemCount();
-        if (itemCount <= 0) {
-            return null;
-        }
-        final ClipData.Item item = clipData.getItemAt(0);
-        if (item == null) {
-            return null;
-        }
-        final CharSequence text = item.getText();
-        return TextUtils.isEmpty(text) ? null : text.toString();
-    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/settings/SettingsActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/settings/SettingsActivity.java
index 6f5a9a7e8..db0c4147c 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/settings/SettingsActivity.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/settings/SettingsActivity.java
@@ -1,24 +1,25 @@
 package it.niedermann.nextcloud.deck.ui.settings;
 
+import android.content.Context;
+import android.content.Intent;
 import android.os.Bundle;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.appcompat.app.AppCompatActivity;
 
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.databinding.ActivitySettingsBinding;
-import it.niedermann.nextcloud.deck.ui.branding.BrandedActivity;
 import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
 
-public class SettingsActivity extends BrandedActivity {
-
-    private ActivitySettingsBinding binding;
+public class SettingsActivity extends AppCompatActivity {
 
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         Thread.currentThread().setUncaughtExceptionHandler(new ExceptionHandler(this));
 
-        binding = ActivitySettingsBinding.inflate(getLayoutInflater());
+        final ActivitySettingsBinding binding = ActivitySettingsBinding.inflate(getLayoutInflater());
         setContentView(binding.getRoot());
 
         setSupportActionBar(binding.toolbar);
@@ -36,8 +37,8 @@ public class SettingsActivity extends BrandedActivity {
         return true;
     }
 
-    @Override
-    public void applyBrand(int mainColor) {
-        // Nothing to do...
+    @NonNull
+    public static Intent createIntent(@NonNull Context context) {
+        return new Intent(context, SettingsActivity.class);
     }
 }
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 04429f225..91c7ad995 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
@@ -1,29 +1,30 @@
 package it.niedermann.nextcloud.deck.ui.settings;
 
 import android.app.Activity;
-import android.content.Context;
 import android.os.Bundle;
+import android.view.View;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.core.app.ActivityCompat;
 import androidx.preference.ListPreference;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceFragmentCompat;
 
+import it.niedermann.nextcloud.deck.DeckApplication;
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncWorker;
-import it.niedermann.nextcloud.deck.ui.branding.Branded;
 import it.niedermann.nextcloud.deck.ui.branding.BrandedSwitchPreference;
 
 import static it.niedermann.nextcloud.deck.DeckApplication.setAppTheme;
-import static it.niedermann.nextcloud.deck.ui.branding.BrandingUtil.readBrandMainColor;
 
-public class SettingsFragment extends PreferenceFragmentCompat implements Branded {
+public class SettingsFragment extends PreferenceFragmentCompat {
 
     private BrandedSwitchPreference wifiOnlyPref;
-    private BrandedSwitchPreference themePref;
-    private BrandedSwitchPreference brandingPref;
     private BrandedSwitchPreference compactPref;
+    private BrandedSwitchPreference debuggingPref;
+    private BrandedSwitchPreference eTagPref;
 
     @Override
     public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
@@ -34,38 +35,23 @@ public class SettingsFragment extends PreferenceFragmentCompat implements Brande
         if (wifiOnlyPref != null) {
             wifiOnlyPref.setOnPreferenceChangeListener((Preference preference, Object newValue) -> {
                 final Boolean syncOnWifiOnly = (Boolean) newValue;
-                DeckLog.log("syncOnWifiOnly: " + syncOnWifiOnly);
+                DeckLog.log("syncOnWifiOnly:", syncOnWifiOnly);
                 return true;
             });
         } else {
-            DeckLog.error("Could not find preference with key: \"" + getString(R.string.pref_key_wifi_only) + "\"");
+            DeckLog.error("Could not find preference with key: ", getString(R.string.pref_key_wifi_only));
         }
 
-        themePref = findPreference(getString(R.string.pref_key_dark_theme));
+        Preference themePref = findPreference(getString(R.string.pref_key_dark_theme));
         if (themePref != null) {
             themePref.setOnPreferenceChangeListener((Preference preference, Object newValue) -> {
-                final Boolean darkTheme = (Boolean) newValue;
-                DeckLog.log("darkTheme: " + darkTheme);
-                setAppTheme(darkTheme);
+                setAppTheme(Integer.parseInt((String) newValue));
                 requireActivity().setResult(Activity.RESULT_OK);
-                requireActivity().recreate();
+                ActivityCompat.recreate(requireActivity());
                 return true;
             });
         } else {
-            DeckLog.error("Could not find preference with key: \"" + getString(R.string.pref_key_dark_theme) + "\"");
-        }
-
-        brandingPref = findPreference(getString(R.string.pref_key_branding));
-        if (brandingPref != null) {
-            brandingPref.setOnPreferenceChangeListener((Preference preference, Object newValue) -> {
-                final Boolean branding = (Boolean) newValue;
-                DeckLog.log("branding: " + branding);
-                requireActivity().setResult(Activity.RESULT_OK);
-                requireActivity().recreate();
-                return true;
-            });
-        } else {
-            DeckLog.error("Could not find preference with key: \"" + getString(R.string.pref_key_dark_theme) + "\"");
+            DeckLog.error("Could not find preference with key:", getString(R.string.pref_key_dark_theme));
         }
 
         compactPref = findPreference(getString(R.string.pref_key_compact));
@@ -77,24 +63,32 @@ public class SettingsFragment extends PreferenceFragmentCompat implements Brande
                 return true;
             });
         } else {
-            DeckLog.error("Could not find preference with key: \"" + getString(R.string.pref_key_background_sync) + "\"");
+            DeckLog.error("Could not find preference with key", getString(R.string.pref_key_background_sync));
         }
-    }
 
-    @Override
-    public void onStart() {
-        super.onStart();
-        @Nullable Context context = getContext();
-        if (context != null) {
-            applyBrand(readBrandMainColor(context));
+        debuggingPref = findPreference(getString(R.string.pref_key_debugging));
+        if (debuggingPref != null) {
+            debuggingPref.setOnPreferenceChangeListener((Preference preference, Object newValue) -> {
+                DeckLog.enablePersistentLogs((Boolean) newValue);
+                DeckLog.log("persistet debug logs:", newValue);
+                return true;
+            });
+        } else {
+            DeckLog.error("Could not find preference with key:", getString(R.string.pref_key_debugging));
         }
+
+        eTagPref = findPreference(getString(R.string.pref_key_etags));
     }
 
     @Override
-    public void applyBrand(int mainColor) {
-        wifiOnlyPref.applyBrand(mainColor);
-        themePref.applyBrand(mainColor);
-        brandingPref.applyBrand(mainColor);
-        compactPref.applyBrand(mainColor);
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+
+        DeckApplication.readCurrentAccountColor().observe(getViewLifecycleOwner(), (mainColor) -> {
+            wifiOnlyPref.applyBrand(mainColor);
+            compactPref.applyBrand(mainColor);
+            debuggingPref.applyBrand(mainColor);
+            eTagPref.applyBrand(mainColor);
+        });
     }
 }
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 3a0005fb1..21aafed30 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
@@ -23,6 +23,7 @@ import java.util.List;
 
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
 import it.niedermann.nextcloud.deck.exceptions.UploadAttachmentFailedException;
 import it.niedermann.nextcloud.deck.model.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
@@ -37,7 +38,7 @@ import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 import it.niedermann.nextcloud.deck.util.MimeTypeUtil;
 
 import static it.niedermann.nextcloud.deck.persistence.sync.adapters.db.util.LiveDataHelper.observeOnce;
-import static it.niedermann.nextcloud.deck.util.AttachmentUtil.copyContentUriToTempFile;
+import static it.niedermann.nextcloud.deck.util.FilesUtil.copyContentUriToTempFile;
 import static java.net.HttpURLConnection.HTTP_CONFLICT;
 
 public class ShareTargetActivity extends MainActivity implements SelectCardListener {
@@ -125,19 +126,23 @@ public class ShareTargetActivity extends MainActivity implements SelectCardListe
                     if (mimeType == null) {
                         throw new IllegalArgumentException("MimeType of uri is null. [" + uri + "]");
                     }
-                    runOnUiThread(() -> {
-                        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) {
+                    mainViewModel.addAttachmentToCard(fullCard.getAccountId(), fullCard.getCard().getLocalId(), mimeType, tempFile, new ResponseCallback<Attachment>() {
+                        @Override
+                        public void onResponse(Attachment response) {
+                            runOnUiThread(shareProgressViewModel::increaseProgress);
+                        }
+
+                        @Override
+                        public void onError(Throwable throwable) {
+                            runOnUiThread(() -> {
+                                if (throwable instanceof NextcloudHttpRequestFailedException && ((NextcloudHttpRequestFailedException) throwable).getStatusCode() == HTTP_CONFLICT) {
+                                    ResponseCallback.super.onError(throwable);
                                     shareProgressViewModel.addDuplicateAttachment(tempFile.getName());
                                 } else {
-                                    shareProgressViewModel.addException(liveData.getError());
+                                    shareProgressViewModel.addException(throwable);
                                 }
-                            } else {
-                                shareProgressViewModel.increaseProgress();
-                            }
-                        });
+                            });
+                        }
                     });
                 } catch (Throwable t) {
                     runOnUiThread(() -> shareProgressViewModel.addException(new UploadAttachmentFailedException("Error while uploading attachment for uri [" + uri + "]", t)));
@@ -154,7 +159,7 @@ public class ShareTargetActivity extends MainActivity implements SelectCardListe
                     switch (which) {
                         case 0:
                             final String oldDescription = fullCard.getCard().getDescription();
-                            DeckLog.info("Adding to card #" + fullCard.getCard().getId() + " (" + fullCard.getCard().getTitle() + "): Text \"" + receivedText + "\"");
+                            DeckLog.info("Adding to card with id", fullCard.getCard().getId(), "(" + fullCard.getCard().getTitle() + "):", receivedText);
                             fullCard.getCard().setDescription(
                                     (oldDescription == null || oldDescription.length() == 0)
                                             ? receivedText
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 8fc56759f..1e0fd4e72 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
@@ -14,8 +14,8 @@ public class StackAdapter extends FragmentStateAdapter {
     @NonNull
     private final List<Stack> stackList = new ArrayList<>();
 
-    public StackAdapter(@NonNull FragmentActivity fragmentActivity) {
-        super(fragmentActivity);
+    public StackAdapter(final FragmentActivity fa) {
+        super(fa);
     }
 
     @Override
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 313e6e821..80440b9d0 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
@@ -81,7 +81,7 @@ public class StackFragment extends BrandedFragment implements DragAndDropTab<Car
             return binding.getRoot();
         }
 
-        adapter = new CardAdapter(requireContext(), getChildFragmentManager(), stackId, mainViewModel, this,
+        adapter = new CardAdapter(requireActivity(), getChildFragmentManager(), stackId, mainViewModel, this,
                 (requireActivity() instanceof SelectCardListener)
                         ? (SelectCardListener) requireActivity()
                         : null);
@@ -159,7 +159,7 @@ public class StackFragment extends BrandedFragment implements DragAndDropTab<Car
             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 + "\"");
+                DeckLog.log("Moved", Card.class.getSimpleName(), originCardLocalId, "to", Stack.class.getSimpleName(), targetStackLocalId);
             }
         });
     }
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
index af17464dc..e1398bab7 100644
--- 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
@@ -9,10 +9,10 @@ import android.util.Size;
 import android.view.OrientationEventListener;
 import android.view.Surface;
 import android.view.View;
+import android.widget.Toast;
 
 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;
@@ -34,12 +34,10 @@ 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 it.niedermann.nextcloud.deck.util.FilesUtil;
 
-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;
@@ -81,8 +79,9 @@ public class TakePhotoActivity extends BrandedActivity {
                     cameraProvider.unbindAll();
                     cameraProvider.bindToLifecycle(this, viewModel.getCameraSelector(), captureUseCase, previewUseCase);
                 });
-            } catch (ExecutionException | InterruptedException e) {
+            } catch (IllegalArgumentException | ExecutionException | InterruptedException e) {
                 DeckLog.logError(e);
+                Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
                 finish();
             }
         }, ContextCompat.getMainExecutor(this));
@@ -118,13 +117,13 @@ public class TakePhotoActivity extends BrandedActivity {
             binding.takePhoto.setEnabled(false);
             final String photoFileName = Instant.now().atZone(ZoneId.systemDefault()).format(fileNameFromCameraFormatter);
             try {
-                final File photoFile = AttachmentUtil.getTempCacheFile(this, "photos/" + photoFileName);
+                final File photoFile = FilesUtil.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());
+                        DeckLog.info("onImageSaved - savedUri:", savedUri.toString());
                         setResult(RESULT_OK, new Intent().setDataAndType(savedUri, IMAGE_JPEG));
                         finish();
                     }
@@ -167,7 +166,6 @@ public class TakePhotoActivity extends BrandedActivity {
         }
     }
 
-    @RequiresApi(LOLLIPOP)
     public static Intent createIntent(@NonNull Context context) {
         return new Intent(context, TakePhotoActivity.class).setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
     }
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
index 0912a07dd..730ecbdd1 100644
--- 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
@@ -1,8 +1,6 @@
 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;
@@ -21,7 +19,6 @@ public class SquareConstraintLayout extends ConstraintLayout {
         super(context, attrs, defStyleAttr);
     }
 
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
     public SquareConstraintLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
         super(context, attrs, defStyleAttr, defStyleRes);
     }
@@ -29,6 +26,7 @@ public class SquareConstraintLayout extends ConstraintLayout {
     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         // Set a square layout.
+        //noinspection SuspiciousNameCombination
         super.onMeasure(widthMeasureSpec, widthMeasureSpec);
     }
 
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/SquareRelativeLayout.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/SquareRelativeLayout.java
index 7f3649c94..cdce90251 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/SquareRelativeLayout.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/view/SquareRelativeLayout.java
@@ -1,8 +1,6 @@
 package it.niedermann.nextcloud.deck.ui.view;
 
-import android.annotation.TargetApi;
 import android.content.Context;
-import android.os.Build;
 import android.util.AttributeSet;
 import android.widget.RelativeLayout;
 
@@ -20,7 +18,6 @@ public class SquareRelativeLayout extends RelativeLayout {
         super(context, attrs, defStyleAttr);
     }
 
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
     public SquareRelativeLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
         super(context, attrs, defStyleAttr, defStyleRes);
     }
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidget.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidget.java
new file mode 100644
index 000000000..89d75eeee
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidget.java
@@ -0,0 +1,78 @@
+package it.niedermann.nextcloud.deck.ui.widget.filter;
+
+import android.appwidget.AppWidgetManager;
+import android.appwidget.AppWidgetProvider;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Bundle;
+
+import java.util.NoSuchElementException;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+
+import static android.appwidget.AppWidgetManager.ACTION_APPWIDGET_UPDATE;
+
+public class FilterWidget extends AppWidgetProvider {
+    public static final String ACCOUNT_KEY = "filter_widget_account";
+    public static final String BUNDLE_KEY = "filter_widget_bundle";
+
+    static void updateAppWidget(Context context, AppWidgetManager awm, int[] appWidgetIds, Account account) {
+        final SyncManager syncManager = new SyncManager(context);
+
+        for (int appWidgetId : appWidgetIds) {
+            new Thread(() -> {
+                try {
+                    // TODO implement
+                    throw new UnsupportedOperationException("Not yet implemented");
+                } 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(FilterWidget.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, FilterWidget.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.deleteFilterWidget(appWidgetId, response -> DeckLog.verbose("Successfully deleted " + FilterWidget.class.getSimpleName() + " with id " + appWidgetId));
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetConfigurationActivity.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetConfigurationActivity.java
new file mode 100644
index 000000000..102860d7c
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetConfigurationActivity.java
@@ -0,0 +1,67 @@
+package it.niedermann.nextcloud.deck.ui.widget.filter;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Intent;
+import android.os.Bundle;
+
+import androidx.appcompat.app.ActionBar;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.lifecycle.ViewModelProvider;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.databinding.ActivityFilterWidgetBinding;
+import it.niedermann.nextcloud.deck.ui.exception.ExceptionHandler;
+
+public class FilterWidgetConfigurationActivity extends AppCompatActivity {
+    private int appWidgetId;
+    private ActivityFilterWidgetBinding binding;
+    private FilterWidgetViewModel viewModel;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        Thread.setDefaultUncaughtExceptionHandler(new ExceptionHandler(this));
+
+        binding = ActivityFilterWidgetBinding.inflate(getLayoutInflater());
+        viewModel = new ViewModelProvider(this).get(FilterWidgetViewModel.class);
+
+        setContentView(binding.getRoot());
+        setSupportActionBar(binding.toolbar);
+
+        final ActionBar actionBar = getSupportActionBar();
+        if (actionBar != null) {
+            actionBar.setTitle(R.string.add_filter_widget);
+        }
+
+        setResult(RESULT_CANCELED);
+        final Bundle args = getIntent().getExtras();
+
+        if (args != null) {
+            appWidgetId = args.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
+        }
+
+        if (appWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID) {
+            DeckLog.error("INVALID_APPWIDGET_ID");
+            finish();
+        }
+        binding.cancel.setOnClickListener((v) -> finish());
+        binding.submit.setOnClickListener((v) -> {
+            final Bundle extras = new Bundle();
+
+            viewModel.updateFilterWidget(response -> DeckLog.verbose("Successfully updated", FilterWidget.class.getSimpleName(), "with id", appWidgetId));
+            Intent updateIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE, null, getApplicationContext(), FilterWidget.class);
+            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(FilterWidget.BUNDLE_KEY, extras);
+            setResult(RESULT_OK, updateIntent);
+            getApplicationContext().sendBroadcast(updateIntent);
+
+            finish();
+        });
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetFactory.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetFactory.java
new file mode 100644
index 000000000..fbc3900f7
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetFactory.java
@@ -0,0 +1,90 @@
+package it.niedermann.nextcloud.deck.ui.widget.filter;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Context;
+import android.content.Intent;
+import android.widget.RemoteViews;
+import android.widget.RemoteViewsService;
+
+import androidx.annotation.NonNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.model.widget.filter.dto.FilterWidgetCard;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+
+public class FilterWidgetFactory implements RemoteViewsService.RemoteViewsFactory {
+    private final Context context;
+    private final int appWidgetId;
+    private final SyncManager syncManager;
+
+    @NonNull
+    private final List<FilterWidgetCard> data = new ArrayList<>();
+
+    FilterWidgetFactory(Context context, Intent intent) {
+        this.context = context;
+        this.appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
+        this.syncManager = new SyncManager(context);
+    }
+
+    @Override
+    public void onCreate() {
+    }
+
+    @Override
+    public void onDataSetChanged() {
+
+    }
+
+
+    @Override
+    public void onDestroy() {
+
+    }
+
+    @Override
+    public int getCount() {
+        return data.size();
+    }
+
+    @Override
+    public RemoteViews getViewAt(int i) {
+        RemoteViews widget_entry;
+
+        if (i > (data.size() - 1) || data.get(i) == null) {
+            DeckLog.error("Card not found at position", i);
+            return null;
+        }
+
+        FullCard card = data.get(i).getCard();
+
+        widget_entry = new RemoteViews(context.getPackageName(), R.layout.widget_stack_entry);
+        widget_entry.setTextViewText(R.id.widget_entry_content_tv, card.card.getTitle());
+
+        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;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetService.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetService.java
new file mode 100644
index 000000000..20c4350ba
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetService.java
@@ -0,0 +1,11 @@
+package it.niedermann.nextcloud.deck.ui.widget.filter;
+
+import android.content.Intent;
+import android.widget.RemoteViewsService;
+
+public class FilterWidgetService extends RemoteViewsService {
+    @Override
+    public RemoteViewsFactory onGetViewFactory(Intent intent) {
+        return new FilterWidgetFactory(this.getApplicationContext(), intent);
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetViewModel.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetViewModel.java
new file mode 100644
index 000000000..4f50465f2
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/filter/FilterWidgetViewModel.java
@@ -0,0 +1,33 @@
+package it.niedermann.nextcloud.deck.ui.widget.filter;
+
+import android.app.Application;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidget;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+
+public class FilterWidgetViewModel extends AndroidViewModel {
+
+    @NonNull
+    private final SyncManager syncManager;
+    @NonNull
+    private final MutableLiveData<FilterWidget> config$ = new MutableLiveData<>(new FilterWidget());
+
+    public FilterWidgetViewModel(@NonNull Application application) {
+        super(application);
+        this.syncManager = new SyncManager(application);
+    }
+
+    public LiveData<FilterWidget> getFilterWidgetConfiguration() {
+        return this.config$;
+    }
+
+    public void updateFilterWidget(@NonNull ResponseCallback<Integer> callback) {
+        syncManager.createFilterWidget(config$.getValue(), callback);
+    }
+}
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 b44b80d1b..766948062 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
@@ -6,11 +6,11 @@ import android.appwidget.AppWidgetProvider;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
-import android.os.Build;
+import android.net.Uri;
+import android.text.TextUtils;
 import android.view.View;
 import android.widget.RemoteViews;
 
-import androidx.annotation.DrawableRes;
 import androidx.annotation.IdRes;
 import androidx.annotation.NonNull;
 
@@ -36,11 +36,21 @@ public class SingleCardWidget extends AppWidgetProvider {
                     final Intent intent = EditActivity.createEditCardIntent(context, fullModel.getAccount(), fullModel.getModel().getBoardId(), fullModel.getFullCard().getLocalId());
                     final PendingIntent pendingIntent = PendingIntent.getActivity(context, appWidgetId, intent, PendingIntent.FLAG_UPDATE_CURRENT);
                     final RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_single_card);
+                    final Intent serviceIntent = new Intent(context, SingleCardWidgetService.class);
 
-                    views.setOnClickPendingIntent(R.id.widget_card, pendingIntent);
+                    serviceIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
+                    serviceIntent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME)));
+
+                    if (TextUtils.isEmpty(SingleCardWidgetFactory.getDescriptionOrNull(fullModel))) {
+                        views.setViewVisibility(R.id.description_lv, View.GONE);
+                    } else {
+                        views.setViewVisibility(R.id.description_lv, View.VISIBLE);
+                    }
 
+                    views.setOnClickPendingIntent(R.id.widget_card, pendingIntent);
+                    views.setPendingIntentTemplate(R.id.description_lv, pendingIntent);
                     views.setTextViewText(R.id.title, fullModel.getFullCard().getCard().getTitle());
-                    views.setTextViewText(R.id.description, fullModel.getFullCard().getCard().getDescription());
+                    views.setRemoteAdapter(R.id.description_lv, serviceIntent);
 
                     if (fullModel.getFullCard().getCard().getDueDate() != null) {
                         views.setTextViewText(R.id.card_due_date, DateUtil.getRelativeDateTimeString(context, fullModel.getFullCard().getCard().getDueDate().toEpochMilli()));
@@ -49,7 +59,7 @@ public class SingleCardWidget extends AppWidgetProvider {
                         // Because otherwise using Reflection is the only way
                         views.setViewVisibility(R.id.card_due_date, View.VISIBLE);
                         views.setViewVisibility(R.id.card_due_date_image, View.VISIBLE);
-                        setImageDrawable(views, R.id.card_due_date_image, R.drawable.calendar_blank_grey600_24dp);
+                        views.setImageViewResource(R.id.card_due_date_image, R.drawable.calendar_blank_grey600_24dp);
                     } else {
                         views.setViewVisibility(R.id.card_due_date, View.GONE);
                         views.setViewVisibility(R.id.card_due_date_image, View.GONE);
@@ -65,8 +75,8 @@ public class SingleCardWidget extends AppWidgetProvider {
                     } else {
                         views.setViewVisibility(R.id.card_count_attachments, View.VISIBLE);
                         views.setViewVisibility(R.id.card_count_attachments_image, View.VISIBLE);
+                        views.setImageViewResource(R.id.card_count_attachments_image, R.drawable.ic_attach_file_grey600_24dp);
                         setupCounter(views, R.id.card_count_attachments, attachmentsCount, counterMaxValue);
-                        setImageDrawable(views, R.id.card_count_attachments_image, R.drawable.ic_check_grey600_24dp);
                     }
 
                     final int commentsCount = fullModel.getFullCard().getCommentCount();
@@ -76,8 +86,8 @@ public class SingleCardWidget extends AppWidgetProvider {
                     } else {
                         views.setViewVisibility(R.id.card_count_comments, View.VISIBLE);
                         views.setViewVisibility(R.id.card_count_comments_image, View.VISIBLE);
+                        views.setImageViewResource(R.id.card_count_comments_image, R.drawable.ic_comment_white_24dp);
                         setupCounter(views, R.id.card_count_comments, commentsCount, counterMaxValue);
-                        setImageDrawable(views, R.id.card_count_comments_image, R.drawable.ic_comment_white_24dp);
                     }
 
                     final Card.TaskStatus taskStatus = fullModel.getFullCard().getCard().getTaskStatus();
@@ -85,13 +95,14 @@ public class SingleCardWidget extends AppWidgetProvider {
                         views.setViewVisibility(R.id.card_count_tasks, View.VISIBLE);
                         views.setViewVisibility(R.id.card_count_tasks_image, View.VISIBLE);
                         views.setTextViewText(R.id.card_count_tasks, context.getResources().getString(R.string.task_count, String.valueOf(taskStatus.doneCount), String.valueOf(taskStatus.taskCount)));
-                        setImageDrawable(views, R.id.card_count_tasks_image, R.drawable.ic_attach_file_grey600_24dp);
+                        views.setImageViewResource(R.id.card_count_tasks_image, R.drawable.ic_check_grey600_24dp);
                     } else {
                         views.setViewVisibility(R.id.card_count_tasks, View.GONE);
                         views.setViewVisibility(R.id.card_count_tasks_image, View.GONE);
                     }
 
                     awm.updateAppWidget(appWidgetId, views);
+                    awm.notifyAppWidgetViewDataChanged(appWidgetId, R.id.description_lv);
                 } catch (NoSuchElementException e) {
                     // onUpdate has been triggered before the user finished configuring the widget
                 }
@@ -102,19 +113,13 @@ public class SingleCardWidget extends AppWidgetProvider {
     private static void setupCounter(@NonNull RemoteViews views, @IdRes int textViewId, int count, String counterMaxValue) {
         if (count > 99) {
             views.setTextViewText(textViewId, counterMaxValue);
-        } else if (count > 1 || Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+        } else if (count > 1) {
             views.setTextViewText(textViewId, String.valueOf(count));
         } else if (count == 1) {
             views.setTextViewText(textViewId, "");
         }
     }
 
-    private static void setImageDrawable(@NonNull RemoteViews views, @IdRes int imageView, @DrawableRes int image) {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
-            views.setImageViewResource(imageView, image);
-        }
-    }
-
     @Override
     public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
         super.onUpdate(context, appWidgetManager, appWidgetIds);
@@ -124,10 +129,9 @@ public class SingleCardWidget extends AppWidgetProvider {
     @Override
     public void onReceive(Context context, Intent intent) {
         super.onReceive(context, intent);
-        AppWidgetManager awm = AppWidgetManager.getInstance(context);
+        final AppWidgetManager awm = AppWidgetManager.getInstance(context);
 
-        updateAppWidget(context, AppWidgetManager.getInstance(context),
-                (awm.getAppWidgetIds(new ComponentName(context, SingleCardWidget.class))));
+        updateAppWidget(context, AppWidgetManager.getInstance(context), (awm.getAppWidgetIds(new ComponentName(context, SingleCardWidget.class))));
     }
 
     @Override
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidgetFactory.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidgetFactory.java
new file mode 100644
index 000000000..db24afa43
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidgetFactory.java
@@ -0,0 +1,100 @@
+package it.niedermann.nextcloud.deck.ui.widget.singlecard;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Context;
+import android.content.Intent;
+import android.text.TextUtils;
+import android.widget.RemoteViews;
+import android.widget.RemoteViewsService;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import java.util.NoSuchElementException;
+
+import it.niedermann.android.markdown.MarkdownUtil;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.full.FullSingleCardWidgetModel;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.ui.card.EditActivity;
+
+public class SingleCardWidgetFactory implements RemoteViewsService.RemoteViewsFactory {
+    private final Context context;
+    private final int appWidgetId;
+    private final SyncManager syncManager;
+    private FullSingleCardWidgetModel model;
+
+    public SingleCardWidgetFactory(@NonNull Context context, @NonNull Intent intent) {
+        this.context = context;
+        this.appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
+        this.syncManager = new SyncManager(context);
+    }
+
+    @Override
+    public void onCreate() {
+
+    }
+
+    @Override
+    public void onDataSetChanged() {
+        try {
+            this.model = syncManager.getSingleCardWidgetModelDirectly(appWidgetId);
+        } catch (NoSuchElementException e) {
+            this.model = null;
+        }
+    }
+
+    @Override
+    public void onDestroy() {
+
+    }
+
+    @Override
+    public int getCount() {
+        return getDescriptionOrNull(model) == null ? 0 : 1;
+    }
+
+    @Override
+    public RemoteViews getViewAt(int position) {
+        final String description = getDescriptionOrNull(model);
+        if (description == null) {
+            return null;
+        }
+
+        final RemoteViews widget_entry = new RemoteViews(context.getPackageName(), R.layout.widget_single_card_content);
+        widget_entry.setTextViewText(R.id.description, MarkdownUtil.renderForRemoteView(context, description));
+
+        final Intent intent = EditActivity.createEditCardIntent(context, model.getAccount(), model.getModel().getBoardId(), model.getFullCard().getCard().getLocalId());
+        widget_entry.setOnClickFillInIntent(R.id.description, intent);
+
+        return widget_entry;
+    }
+
+    @Override
+    public RemoteViews getLoadingView() {
+        return null;
+    }
+
+    @Override
+    public int getViewTypeCount() {
+        return 1;
+    }
+
+    @Override
+    public long getItemId(int position) {
+        return position;
+    }
+
+    @Override
+    public boolean hasStableIds() {
+        return true;
+    }
+
+    @Nullable
+    public static String getDescriptionOrNull(@Nullable FullSingleCardWidgetModel model) {
+        if (model == null || model.getFullCard() == null || model.getFullCard().getCard() == null || TextUtils.isEmpty(model.getFullCard().getCard().getDescription())) {
+            return null;
+        }
+        return model.getFullCard().getCard().getDescription();
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidgetService.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidgetService.java
new file mode 100644
index 000000000..d938e383a
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/singlecard/SingleCardWidgetService.java
@@ -0,0 +1,11 @@
+package it.niedermann.nextcloud.deck.ui.widget.singlecard;
+
+import android.content.Intent;
+import android.widget.RemoteViewsService;
+
+public class SingleCardWidgetService extends RemoteViewsService {
+    @Override
+    public RemoteViewsFactory onGetViewFactory(Intent intent) {
+        return new SingleCardWidgetFactory(this.getApplicationContext(), intent);
+    }
+}
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
index cb179953c..5b0907ef3 100644
--- 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
@@ -7,14 +7,13 @@ 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 androidx.annotation.ColorInt;
 
+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.appwidgets.StackWidgetModel;
+import it.niedermann.nextcloud.deck.model.Stack;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 import it.niedermann.nextcloud.deck.ui.MainActivity;
 import it.niedermann.nextcloud.deck.ui.card.EditActivity;
@@ -22,82 +21,29 @@ 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);
+        updateAppWidget(context, appWidgetManager, appWidgetIds);
     }
 
     @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);
-                    }
-                }
+        final AppWidgetManager awm = AppWidgetManager.getInstance(context);
+
+        if (ACTION_APPWIDGET_UPDATE.equals(intent.getAction())) {
+            if (intent.hasExtra(AppWidgetManager.EXTRA_APPWIDGET_ID)) {
+                final int appWidgetId = intent.getExtras().getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, -1);
+                DeckLog.verbose(ACTION_APPWIDGET_UPDATE, "for", StackWidget.class.getSimpleName(), "with id", appWidgetId, "→ perform update.");
+                updateAppWidget(context, awm, new int[]{appWidgetId});
+            } else {
+                DeckLog.verbose(ACTION_APPWIDGET_UPDATE, "→ Triggering update for all widgets of type", StackWidget.class.getSimpleName());
+                updateAppWidget(context, awm, awm.getAppWidgetIds(new ComponentName(context, StackWidget.class)));
             }
         }
     }
@@ -108,14 +54,47 @@ public class StackWidget extends AppWidgetProvider {
         final SyncManager syncManager = new SyncManager(context);
 
         for (int appWidgetId : appWidgetIds) {
-            syncManager.deleteStackWidgetModel(appWidgetId);
+            DeckLog.info("Delete", StackWidget.class.getSimpleName(), "with id", appWidgetId);
+            syncManager.deleteFilterWidget(appWidgetId, response -> DeckLog.verbose("Successfully deleted " + StackWidget.class.getSimpleName() + " with id " + 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));
+    private static void updateAppWidget(Context context, AppWidgetManager awm, int[] appWidgetIds) {
+        final SyncManager syncManager = new SyncManager(context);
+        for (int appWidgetId : appWidgetIds) {
+            new Thread(() -> {
+                if (syncManager.filterWidgetExists(appWidgetId)) {
+                    final RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_stack);
+
+                    final Intent serviceIntent = new Intent(context, StackWidgetService.class);
+                    serviceIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
+                    serviceIntent.setData(Uri.parse(serviceIntent.toUri(Intent.URI_INTENT_SCHEME)));
+
+                    final Intent intent = new Intent(Intent.ACTION_MAIN).setComponent(new ComponentName(context.getPackageName(), MainActivity.class.getName()));
+                    final PendingIntent pendingIntent = PendingIntent.getActivity(context, PENDING_INTENT_OPEN_APP_RQ,
+                            intent, PendingIntent.FLAG_UPDATE_CURRENT);
+                    final PendingIntent templatePI = PendingIntent.getActivity(context, PENDING_INTENT_EDIT_CARD_RQ,
+                            new Intent(context, EditActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);
+
+                    views.setOnClickPendingIntent(R.id.widget_stack_header_rl, pendingIntent);
+
+                    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);
+
+                    syncManager.getFilterWidget(appWidgetId, response -> {
+                        final Stack stack = syncManager.getStackDirectly(response.getAccounts().get(0).getBoards().get(0).getStacks().get(0).getStackId());
+                        @ColorInt final Integer boardColor = syncManager.getBoardColorDirectly(response.getAccounts().get(0).getAccountId(), response.getAccounts().get(0).getBoards().get(0).getBoardId());
+                        views.setTextViewText(R.id.widget_stack_title_tv, stack.getTitle());
+                        views.setInt(R.id.widget_stack_header_icon, "setColorFilter", boardColor);
+
+                        awm.notifyAppWidgetViewDataChanged(appWidgetId, R.id.stack_widget_lv);
+                        awm.updateAppWidget(appWidgetId, views);
+                    });
+                } else {
+                    DeckLog.warn("Does not yet exist");
+                }
+            }).start();
+        }
     }
 }
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
index 96b5cf672..a34123e29 100644
--- 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
@@ -7,10 +7,19 @@ import android.os.Bundle;
 import androidx.appcompat.app.ActionBar;
 import androidx.lifecycle.ViewModelProvider;
 
+import java.util.Collections;
+
 import it.niedermann.nextcloud.deck.DeckLog;
 import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
 import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.widget.filter.EWidgetType;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidget;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetAccount;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetBoard;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetStack;
 import it.niedermann.nextcloud.deck.ui.PickStackActivity;
+import it.niedermann.nextcloud.deck.ui.exception.ExceptionDialogFragment;
 
 public class StackWidgetConfigurationActivity extends PickStackActivity {
     private int appWidgetId;
@@ -43,22 +52,35 @@ public class StackWidgetConfigurationActivity extends PickStackActivity {
 
     @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();
+        final FilterWidget config = new FilterWidget(appWidgetId, EWidgetType.STACK_WIDGET);
+        final FilterWidgetAccount filterWidgetAccount = new FilterWidgetAccount(account.getId(), false);
+        filterWidgetAccount.setIncludeNoProject(false);
+        FilterWidgetBoard filterWidgetBoard = new FilterWidgetBoard(boardId, Collections.singletonList(new FilterWidgetStack(stackId)));
+        filterWidgetBoard.setIncludeNoLabel(false);
+        filterWidgetAccount.setBoards(
+                Collections.singletonList(filterWidgetBoard));
+        config.setAccounts(Collections.singletonList(filterWidgetAccount));
+        stackWidgetConfigurationViewModel.addStackWidget(config, new IResponseCallback<Integer>(account) {
+
+            @Override
+            public void onResponse(Integer response) {
+                final Intent updateIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE, null,
+                        getApplicationContext(), StackWidget.class)
+                        .putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
+                setResult(RESULT_OK, updateIntent);
+                getApplicationContext().sendBroadcast(updateIntent);
+
+                finish();
+            }
+
+            @Override
+            public void onError(Throwable throwable) {
+                super.onError(throwable);
+                ExceptionDialogFragment
+                        .newInstance(throwable, account)
+                        .show(getSupportFragmentManager(), ExceptionDialogFragment.class.getSimpleName());
+            }
+        });
     }
 
     @Override
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
index cc669accf..54ae5635e 100644
--- 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
@@ -5,6 +5,8 @@ import android.app.Application;
 import androidx.annotation.NonNull;
 import androidx.lifecycle.AndroidViewModel;
 
+import it.niedermann.nextcloud.deck.api.IResponseCallback;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidget;
 import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
 
 @SuppressWarnings("WeakerAccess")
@@ -17,7 +19,7 @@ public class StackWidgetConfigurationViewModel extends AndroidViewModel {
         this.syncManager = new SyncManager(application);
     }
 
-    public void addStackWidget(int appWidgetId, long accountId, long stackId, boolean darkTheme) {
-        syncManager.addStackWidget(appWidgetId, accountId, stackId, darkTheme);
+    public void addStackWidget(@NonNull FilterWidget config, @NonNull IResponseCallback<Integer> callback) {
+        syncManager.createFilterWidget(config, callback);
     }
 }
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
index 87f357e20..e44fd9876 100644
--- 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
@@ -1,76 +1,58 @@
 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 androidx.annotation.NonNull;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.List;
+import java.util.NoSuchElementException;
 
 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.model.widget.filter.dto.FilterWidgetCard;
 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 final SyncManager syncManager;
 
-    private Account account;
-    private FullStack stack;
-    private List<FullCard> cardList;
+    @NonNull
+    private final List<FilterWidgetCard> data = new ArrayList<>();
 
     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);
-        }
+        this.syncManager = new SyncManager(context);
     }
 
     @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);
-            }
-        });
+        // Nothing to do here...
     }
 
     @Override
     public void onDataSetChanged() {
-
+        try {
+            final List<FilterWidgetCard> response = syncManager.getCardsForFilterWidget(appWidgetId);
+            DeckLog.verbose(StackWidget.class.getSimpleName(), "with id", appWidgetId, "fetched", response.size(), "cards from the database.");
+            data.clear();
+            Collections.sort(response, Comparator.comparingLong(value -> value.getCard().getCard().getOrder()));
+            data.addAll(response);
+        } catch (NoSuchElementException e) {
+            DeckLog.error("No", StackWidget.class.getSimpleName(), "for appWidgetId", appWidgetId, "found.");
+            DeckLog.logError(e);
+        }
     }
 
 
@@ -81,24 +63,22 @@ public class StackWidgetFactory implements RemoteViewsService.RemoteViewsFactory
 
     @Override
     public int getCount() {
-        return stack == null ? 0 : stack.getCards().size();
+        return data.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);
+        if (i > (data.size() - 1) || data.get(i) == null) {
+            DeckLog.error("No card or separator not found at position", i);
             return null;
         }
-
-        FullCard card = cardList.get(i);
+        final RemoteViews widget_entry;
+        final FilterWidgetCard filterWidgetCard = data.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());
+        widget_entry.setTextViewText(R.id.widget_entry_content_tv, filterWidgetCard.getCard().getCard().getTitle());
 
-        final Intent intent = EditActivity.createEditCardIntent(context, account, stack.getStack().getBoardId(), card.getCard().getLocalId());
+        final Intent intent = EditActivity.createEditCardIntent(context,  syncManager.readAccountDirectly(filterWidgetCard.getCard().getAccountId()), filterWidgetCard.getStack().getBoardId(), filterWidgetCard.getCard().getLocalId());
         intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME)));
         widget_entry.setOnClickFillInIntent(R.id.widget_stack_entry, intent);
 
@@ -124,11 +104,4 @@ public class StackWidgetFactory implements RemoteViewsService.RemoteViewsFactory
     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/upcoming/UpcomingWidget.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/upcoming/UpcomingWidget.java
new file mode 100644
index 000000000..bedf5253f
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/upcoming/UpcomingWidget.java
@@ -0,0 +1,124 @@
+package it.niedermann.nextcloud.deck.ui.widget.upcoming;
+
+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.widget.RemoteViews;
+
+import androidx.annotation.NonNull;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.api.ResponseCallback;
+import it.niedermann.nextcloud.deck.model.Account;
+import it.niedermann.nextcloud.deck.model.enums.ESortCriteria;
+import it.niedermann.nextcloud.deck.model.widget.filter.EWidgetType;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidget;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetAccount;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetSort;
+import it.niedermann.nextcloud.deck.model.widget.filter.FilterWidgetUser;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.ui.card.EditActivity;
+
+import static android.appwidget.AppWidgetManager.ACTION_APPWIDGET_UPDATE;
+
+public class UpcomingWidget extends AppWidgetProvider {
+    private static final int PENDING_INTENT_OPEN_APP_RQ = 0;
+    private static final int PENDING_INTENT_EDIT_CARD_RQ = 1;
+
+    @Override
+    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
+        super.onUpdate(context, appWidgetManager, appWidgetIds);
+        final SyncManager syncManager = new SyncManager(context);
+
+        for (int appWidgetId : appWidgetIds) {
+            new Thread(() -> {
+                if (syncManager.filterWidgetExists(appWidgetId)) {
+                    DeckLog.warn(UpcomingWidget.class.getSimpleName(), "with id", appWidgetId, "already exists, perform update instead.");
+                    updateAppWidget(context, appWidgetManager, appWidgetIds);
+                } else {
+                    final List<Account> accountsList = syncManager.readAccountsDirectly();
+                    final FilterWidget config = new FilterWidget(appWidgetId, EWidgetType.UPCOMING_WIDGET);
+                    config.setSorts(new FilterWidgetSort(ESortCriteria.DUE_DATE, true));
+                    config.setAccounts(accountsList.stream().map(account -> {
+                        final FilterWidgetAccount fwa = new FilterWidgetAccount(account.getId(), false);
+                        fwa.setUsers(new FilterWidgetUser(syncManager.getUserByUidDirectly(account.getId(), account.getUserName()).getLocalId()));
+                        return fwa;
+                    }).collect(Collectors.toList()));
+                    syncManager.createFilterWidget(config, new ResponseCallback<Integer>() {
+                        @Override
+                        public void onResponse(Integer response) {
+                            DeckLog.verbose("Successfully created", UpcomingWidget.class.getSimpleName(), "with id", appWidgetId);
+                            updateAppWidget(context, appWidgetManager, appWidgetIds);
+                        }
+
+                        @Override
+                        public void onError(Throwable throwable) {
+                            DeckLog.error("Error while creating", UpcomingWidget.class.getSimpleName(), "with id", appWidgetId);
+                            ResponseCallback.super.onError(throwable);
+                            onDeleted(context, appWidgetIds);
+                        }
+                    });
+                }
+            }).start();
+        }
+    }
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        super.onReceive(context, intent);
+
+        final AppWidgetManager awm = AppWidgetManager.getInstance(context);
+
+        if (ACTION_APPWIDGET_UPDATE.equals(intent.getAction())) {
+            if (intent.hasExtra(AppWidgetManager.EXTRA_APPWIDGET_ID)) {
+                final int appWidgetId = intent.getExtras().getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, -1);
+                DeckLog.verbose(ACTION_APPWIDGET_UPDATE, "for", UpcomingWidget.class.getSimpleName(), "with id", appWidgetId, "→ perform update.");
+                updateAppWidget(context, awm, new int[]{appWidgetId});
+            } else {
+                DeckLog.verbose(ACTION_APPWIDGET_UPDATE, "→ Triggering update for all widgets of type", UpcomingWidget.class.getSimpleName());
+                updateAppWidget(context, awm, awm.getAppWidgetIds(new ComponentName(context, UpcomingWidget.class)));
+            }
+        }
+    }
+
+    @Override
+    public void onDeleted(Context context, int[] appWidgetIds) {
+        super.onDeleted(context, appWidgetIds);
+        final SyncManager syncManager = new SyncManager(context);
+
+        for (int appWidgetId : appWidgetIds) {
+            DeckLog.info("Delete", UpcomingWidget.class.getSimpleName(), "with id", appWidgetId);
+            syncManager.deleteFilterWidget(appWidgetId, response -> DeckLog.verbose("Successfully deleted " + UpcomingWidget.class.getSimpleName() + " with id " + appWidgetId));
+        }
+    }
+
+    private static void updateAppWidget(@NonNull Context context, @NonNull AppWidgetManager awm, int[] appWidgetIds) {
+        for (int appWidgetId : appWidgetIds) {
+            new Thread(() -> {
+                final RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_upcoming);
+
+                final Intent serviceIntent = new Intent(context, UpcomingWidgetService.class);
+                serviceIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
+                serviceIntent.setData(Uri.parse(serviceIntent.toUri(Intent.URI_INTENT_SCHEME)));
+
+                final PendingIntent templatePI = PendingIntent.getActivity(context, PENDING_INTENT_EDIT_CARD_RQ,
+                        new Intent(context, EditActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);
+
+                views.setPendingIntentTemplate(R.id.upcoming_widget_lv, templatePI);
+                views.setRemoteAdapter(R.id.upcoming_widget_lv, serviceIntent);
+                views.setEmptyView(R.id.upcoming_widget_lv, R.id.widget_upcoming_placeholder_iv);
+
+                awm.notifyAppWidgetViewDataChanged(appWidgetId, R.id.upcoming_widget_lv);
+                awm.updateAppWidget(appWidgetId, views);
+            }).start();
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/upcoming/UpcomingWidgetFactory.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/upcoming/UpcomingWidgetFactory.java
new file mode 100644
index 000000000..964c21ffa
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/upcoming/UpcomingWidgetFactory.java
@@ -0,0 +1,224 @@
+package it.niedermann.nextcloud.deck.ui.widget.upcoming;
+
+import android.appwidget.AppWidgetManager;
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+import android.widget.RemoteViews;
+import android.widget.RemoteViewsService;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.annotation.StringRes;
+
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.ZoneId;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+import it.niedermann.android.util.DimensionUtil;
+import it.niedermann.nextcloud.deck.DeckLog;
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
+import it.niedermann.nextcloud.deck.model.widget.filter.dto.FilterWidgetCard;
+import it.niedermann.nextcloud.deck.persistence.sync.SyncManager;
+import it.niedermann.nextcloud.deck.ui.card.EditActivity;
+
+import static java.time.temporal.ChronoUnit.DAYS;
+
+public class UpcomingWidgetFactory implements RemoteViewsService.RemoteViewsFactory {
+    private final Context context;
+    private final int appWidgetId;
+    private final SyncManager syncManager;
+    private final int headerHorizontalPadding;
+    private final int headerVerticalPaddingNth;
+
+    @NonNull
+    private final List<Object> data = new ArrayList<>();
+
+    UpcomingWidgetFactory(@NonNull Context context, Intent intent) {
+        this.context = context;
+        this.appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
+        this.syncManager = new SyncManager(context);
+        this.headerHorizontalPadding = DimensionUtil.INSTANCE.dpToPx(context, R.dimen.spacer_1hx);
+        this.headerVerticalPaddingNth = DimensionUtil.INSTANCE.dpToPx(context, R.dimen.spacer_2x);
+    }
+
+    @Override
+    public void onCreate() {
+        // Nothing to do here...
+    }
+
+    @Override
+    public void onDataSetChanged() {
+        try {
+            final List<FilterWidgetCard> response = syncManager.getCardsForFilterWidget(appWidgetId);
+            DeckLog.verbose(UpcomingWidgetFactory.class.getSimpleName(), "with id", appWidgetId, "fetched", response.size(), "cards from the database.");
+            data.clear();
+            final Comparator<FilterWidgetCard> comparator = Comparator.comparing((card -> {
+                if (card != null &&
+                        card.getCard() != null &&
+                        card.getCard().getCard() != null &&
+                        card.getCard().getCard().getDueDate() != null) {
+                    return card.getCard().getCard().getDueDate();
+                }
+                return null;
+            }), Comparator.nullsLast(Comparator.naturalOrder()));
+            comparator.thenComparing(card -> {
+                if (card != null &&
+                        card.getCard() != null &&
+                        card.getCard().getCard().getDueDate() != null) {
+
+                    Card c = card.getCard().getCard();
+
+                    if (c.getLastModified() == null && c.getLastModifiedLocal() != null) {
+                        return c.getLastModifiedLocal();
+                    } else if (c.getLastModified() != null && c.getLastModifiedLocal() == null) {
+                        return c.getLastModified();
+                    } else {
+                        return c.getLastModifiedLocal().toEpochMilli() > c.getLastModified().toEpochMilli() ?
+                                c.getLastModifiedLocal() : c.getLastModified();
+                    }
+                }
+                return null;
+            }, Comparator.nullsLast(Comparator.naturalOrder()));
+
+            Collections.sort(
+                    response,
+                    comparator
+            );
+            EUpcomingDueType lastDueType = null;
+            for (FilterWidgetCard filterWidgetCard : response) {
+                final EUpcomingDueType nextDueType = getDueType(filterWidgetCard.getCard().getCard().getDueDate());
+                DeckLog.info(filterWidgetCard.getCard().getCard().getTitle() + ":", nextDueType.name());
+                if (!nextDueType.equals(lastDueType)) {
+                    data.add(new Separator(nextDueType.toString(context)));
+                    lastDueType = nextDueType;
+                }
+                data.add(filterWidgetCard);
+            }
+        } catch (NoSuchElementException e) {
+            DeckLog.error("No", UpcomingWidget.class.getSimpleName(), "for appWidgetId", appWidgetId, "found.");
+            DeckLog.logError(e);
+        }
+    }
+
+    @Override
+    public void onDestroy() {
+
+    }
+
+    @Override
+    public int getCount() {
+        return data.size();
+    }
+
+    @Override
+    public RemoteViews getViewAt(int i) {
+        if (i > (data.size() - 1) || data.get(i) == null) {
+            DeckLog.error("No card or separator not found at position", i);
+            return null;
+        }
+        final RemoteViews widget_entry;
+        if (data.get(i).getClass() == Separator.class) {
+            final Separator separator = (Separator) data.get(i);
+            widget_entry = new RemoteViews(context.getPackageName(), R.layout.widget_separator);
+            widget_entry.setTextViewText(R.id.widget_entry_content_tv, separator.title);
+            if(i == 0) {
+                widget_entry.setViewPadding(R.id.widget_entry_content_tv, headerHorizontalPadding, 0, headerHorizontalPadding, 0);
+            } else {
+                widget_entry.setViewPadding(R.id.widget_entry_content_tv, headerHorizontalPadding, headerVerticalPaddingNth, headerHorizontalPadding, 0);
+            }
+        } else {
+            final FullCard card = ((FilterWidgetCard) data.get(i)).getCard();
+            widget_entry = new RemoteViews(context.getPackageName(), R.layout.widget_stack_entry);
+            widget_entry.setTextViewText(R.id.widget_entry_content_tv, card.getCard().getTitle());
+
+            final Long localCardId = card.getCard().getLocalId();
+            final Intent intent = EditActivity.createEditCardIntent(context, syncManager.readAccountDirectly(card.getAccountId()), syncManager.getBoardLocalIdByLocalCardIdDirectly(localCardId), localCardId);
+            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 2;
+    }
+
+    @Override
+    public long getItemId(int i) {
+        return i;
+    }
+
+    @Override
+    public boolean hasStableIds() {
+        return true;
+    }
+
+    @NonNull
+    private static EUpcomingDueType getDueType(@Nullable Instant dueDate) {
+        if (dueDate == null) {
+            return EUpcomingDueType.NO_DUE;
+        }
+
+        long diff = DAYS.between(LocalDate.now(), dueDate.atZone(ZoneId.systemDefault()).toLocalDate());
+
+        if (diff > 7) {
+            return EUpcomingDueType.LATER;
+        } else if (diff > 1) {
+            return EUpcomingDueType.WEEK;
+        } else if (diff > 0) {
+            return EUpcomingDueType.TOMORROW;
+        } else if (diff == 0) {
+            return EUpcomingDueType.TODAY;
+        } else {
+            return EUpcomingDueType.OVERDUE;
+        }
+    }
+
+    private enum EUpcomingDueType {
+        OVERDUE(1, R.string.filter_overdue),
+        TODAY(2, R.string.filter_today),
+        TOMORROW(3, R.string.filter_tomorrow),
+        WEEK(4, R.string.filter_week),
+        LATER(5, R.string.filter_later),
+        NO_DUE(6, R.string.filter_no_due);
+
+        private final int value;
+        private final int id;
+
+        EUpcomingDueType(int id, @StringRes int value) {
+            this.value = value;
+            this.id = id;
+        }
+
+        public int getId() {
+            return id;
+        }
+
+        @NonNull
+        public String toString(Context context) {
+            return context.getString(this.value);
+        }
+    }
+
+    private static class Separator {
+        public String title;
+
+        private Separator(String title) {
+            this.title = title;
+        }
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/upcoming/UpcomingWidgetService.java b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/upcoming/UpcomingWidgetService.java
new file mode 100644
index 000000000..6cbd04549
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/ui/widget/upcoming/UpcomingWidgetService.java
@@ -0,0 +1,11 @@
+package it.niedermann.nextcloud.deck.ui.widget.upcoming;
+
+import android.content.Intent;
+import android.widget.RemoteViewsService;
+
+public class UpcomingWidgetService extends RemoteViewsService {
+    @Override
+    public RemoteViewsFactory onGetViewFactory(Intent intent) {
+        return new UpcomingWidgetFactory(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 ef3e14b37..a4bd5d6d9 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
@@ -12,15 +12,11 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.Px;
 
-import java.io.File;
-import java.io.FileNotFoundException;
-import java.io.FileOutputStream;
-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.Account;
 import it.niedermann.nextcloud.deck.model.Attachment;
+import it.niedermann.nextcloud.deck.model.enums.EAttachmentType;
 import it.niedermann.nextcloud.deck.model.ocs.Version;
 
 /**
@@ -37,90 +33,63 @@ public class AttachmentUtil {
      * 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);
+    public static String getThumbnailUrl(@NonNull Account account, @NonNull Long cardRemoteId, @NonNull Attachment attachment, @Px int previewSize) {
+        return getThumbnailUrl(account, cardRemoteId, attachment, previewSize, previewSize);
+    }
+
+    public static String getThumbnailUrl(@NonNull Account account, @NonNull Long cardRemoteId, @NonNull Attachment attachment, @Px int previewWidth, @Px int previewHeight) {
+        return account.getServerDeckVersionAsObject().supportsFileAttachments() &&
+                EAttachmentType.FILE.equals(attachment.getType()) &&
+                attachment.getFileId() != null
+                ? account.getUrl() + "/index.php/core/preview?fileId=" + attachment.getFileId() + "&x=" + previewWidth + "&y=" + previewHeight + "&a=true"
+                : getRemoteOrLocalUrl(account.getUrl(), cardRemoteId, attachment);
     }
 
     /**
-     * @return {@link AttachmentUtil#getRemoteUrl} or {@link Attachment#getLocalPath()} as fallback
+     * @return {@link AttachmentUtil#getDeck_1_0_RemoteUrl} 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) {
+    private 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());
+                : getDeck_1_0_RemoteUrl(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) {
+    public static void openAttachmentInBrowser(@NonNull Account account, @NonNull Context context, Long cardRemoteId, Attachment attachment) {
         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) {
+
+        try {
+            context.startActivity(new Intent(Intent.ACTION_VIEW).setData(Uri.parse(getCopyDownloadUrl(account, cardRemoteId, attachment))));
+        } catch (IllegalArgumentException e) {
             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 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());
+    public static String getCopyDownloadUrl(@NonNull Account account, @NonNull Long cardRemoteId, @NonNull Attachment attachment) {
+        if (attachment.getId() == null) {
+            throw new IllegalArgumentException("attachment id must not be null");
         }
-        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;
+        return (attachment.getFileId() != null)
+                ? account.getUrl() + "/f/" + attachment.getFileId()
+                : getDeck_1_0_RemoteUrl(account.getUrl(), cardRemoteId, attachment.getId());
     }
 
     /**
-     * Creates a new {@link File}
+     * Attention! This does only work for attachments of type "deck_file" which are a legacy of Deck API 1.0
      */
-    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.getParentFile()");
-        }
-        if (!tempDir.exists()) {
-            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.");
-            }
-        }
-
-        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");
-        }
-
-        return cacheFile;
+    @Deprecated
+    private static String getDeck_1_0_RemoteUrl(@NonNull String accountUrl, @NonNull Long cardRemoteId, @NonNull Long attachmentRemoteId) {
+        return accountUrl + "/index.php/apps/deck/cards/" + cardRemoteId + "/attachment/" + attachmentRemoteId;
     }
 
     @DrawableRes
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/CardUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/CardUtil.java
index f89581c95..4f31b7250 100644
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/CardUtil.java
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/CardUtil.java
@@ -1,9 +1,21 @@
 package it.niedermann.nextcloud.deck.util;
 
+import android.content.Context;
+import android.text.TextUtils;
+
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.time.format.FormatStyle;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+import it.niedermann.nextcloud.deck.R;
+import it.niedermann.nextcloud.deck.model.Card;
+import it.niedermann.nextcloud.deck.model.Label;
+import it.niedermann.nextcloud.deck.model.full.FullCard;
 
 public class CardUtil {
     private static final Pattern pLists = Pattern.compile("^\\s*[*+-]\\s+", Pattern.MULTILINE);
@@ -17,8 +29,34 @@ public class CardUtil {
         // You shall not pass
     }
 
+    /**
+     * @return a human readable String containing the description, due date and tags of the given {@param fullCard}
+     */
+    @NonNull
+    public static String getCardContentAsString(@NonNull Context context, @NonNull FullCard fullCard) {
+        final Card card = fullCard.getCard();
+        String text = card.getDescription();
+        if(card.getDueDate() != null) {
+            if(!TextUtils.isEmpty(text)) {
+                text += "\n";
+            }
+            text += context.getString(R.string.share_content_duedate, card.getDueDate().atZone(ZoneId.systemDefault()).format(DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM)));
+        }
+        if(fullCard.getLabels() != null && !fullCard.getLabels().isEmpty()) {
+            if(!TextUtils.isEmpty(text)) {
+                text += "\n";
+            }
+            text += context.getString(R.string.share_content_labels, fullCard.getLabels().stream().map(Label::getTitle).collect(Collectors.joining(", ")));
+        }
+        return text;
+    }
+
+    public static boolean cardHasCommentsOrAttachments(@NonNull FullCard fullCard) {
+        return fullCard.getCommentCount() > 0 || (fullCard.getAttachments() != null && !fullCard.getAttachments().isEmpty());
+    }
+
     @NonNull
-    public static String generateTitleFromDescription(String description) {
+    public static String generateTitleFromDescription(@Nullable String description) {
         if(description == null) return "";
         return getLineWithoutMarkDown(description, 0);
     }
@@ -32,20 +70,19 @@ public class CardUtil {
      */
     @NonNull
     private static String getLineWithoutMarkDown(@NonNull String content, @SuppressWarnings("SameParameterValue") int lineNumber) {
-        String line = "";
         if (content.contains("\n")) {
-            String[] lines = content.split("\n");
+            final String[] lines = content.split("\n");
             int currentLine = lineNumber;
             while (currentLine < lines.length && isEmptyLine(lines[currentLine])) {
                 currentLine++;
             }
             if (currentLine < lines.length) {
-                line = removeMarkDown(lines[currentLine]);
+                return removeMarkDown(lines[currentLine]);
             }
         } else {
-            line = content;
+            return content;
         }
-        return line;
+        return "";
     }
 
     /**
@@ -61,7 +98,7 @@ public class CardUtil {
      * @param line String - a single Line which ends with \n
      * @return boolean isEmpty
      */
-    private static boolean isEmptyLine(@Nullable String line) {
+    private static boolean isEmptyLine(@NonNull String line) {
         return removeMarkDown(line).trim().length() == 0;
     }
 
@@ -72,9 +109,7 @@ public class CardUtil {
      * @return Plain Text-String
      */
     @NonNull
-    private static String removeMarkDown(@Nullable String s) {
-        if (s == null)
-            return "";
+    private static String removeMarkDown(@NonNull String s) {
         s = pLists.matcher(s).replaceAll("");
         s = pHeadings.matcher(s).replaceAll("$1");
         s = pHeadingLine.matcher(s).replaceAll("");
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 ac88519ff..6fbb9e30e 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
@@ -22,14 +22,14 @@ public final class DateUtil {
             return context.getString(R.string.seconds_ago);
         } else {
             // in the future or past (larger than 60 seconds)
-            CharSequence dateString = DateUtils.getRelativeDateTimeString(
+            final CharSequence dateString = DateUtils.getRelativeDateTimeString(
                     context,
                     time,
                     DateUtils.SECOND_IN_MILLIS,
                     DateUtils.WEEK_IN_MILLIS,
                     0
             );
-            String[] parts = dateString.toString().split(",");
+            final String[] parts = dateString.toString().split(",");
             if (parts.length == DATE_TIME_PARTS_SIZE) {
                 if (parts[1].contains(":") && !parts[0].contains(":")) {
                     return parts[0];
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 1a88bec97..43a9e6299 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
@@ -39,7 +39,9 @@ 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()))
+                    .setCheckable(true);
             if (currentServerVersionIsSupported) {
                 if (board.isPermissionManage()) {
                     AppCompatImageButton contextMenu = new AppCompatImageButton(context);
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/FilesUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/FilesUtil.java
new file mode 100644
index 000000000..6feb4d80c
--- /dev/null
+++ b/app/src/main/java/it/niedermann/nextcloud/deck/util/FilesUtil.java
@@ -0,0 +1,78 @@
+package it.niedermann.nextcloud.deck.util;
+
+import android.content.Context;
+import android.net.Uri;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.WorkerThread;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import it.niedermann.nextcloud.deck.DeckLog;
+
+/**
+ * Created by stefan on 07.03.20.
+ */
+
+public class FilesUtil {
+
+    private FilesUtil() {
+    }
+
+    /**
+     * https://help.nextcloud.com/t/android-app-select-file-with-nextcloud-app-file-cant-be-read/103706
+     * Must not be called from the UI thread because the {@param currentUri} might refer to a not yet locally available file.
+     */
+    @WorkerThread
+    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());
+        }
+        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.getParentFile()");
+        }
+        if (!tempDir.exists()) {
+            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.");
+            }
+        }
+
+        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");
+        }
+
+        return cacheFile;
+    }
+}
diff --git a/app/src/main/java/it/niedermann/nextcloud/deck/util/MarkDownUtil.java b/app/src/main/java/it/niedermann/nextcloud/deck/util/MarkDownUtil.java
deleted file mode 100644
index 9e1e5b147..000000000
--- a/app/src/main/java/it/niedermann/nextcloud/deck/util/MarkDownUtil.java
+++ /dev/null
@@ -1,47 +0,0 @@
-package it.niedermann.nextcloud.deck.util;
-
-import android.content.Context;
-
-import androidx.core.content.ContextCompat;
-import androidx.core.content.res.ResourcesCompat;
-
-import com.yydcdut.rxmarkdown.RxMDConfiguration.Builder;
-
-import it.niedermann.nextcloud.deck.R;
-
-/**
- * Created by stefan on 07.12.16.
- */
-
-public class MarkDownUtil {
-
-    private MarkDownUtil() {}
-
-    /**
-     * Ensures every instance of RxMD uses the same configuration
-     *
-     * @param context Context
-     * @return RxMDConfiguration
-     */
-    public static Builder getMarkDownConfiguration(Context context) {
-        return new Builder(context)
-                .setHeader2RelativeSize(1.35f)
-                .setHeader3RelativeSize(1.25f)
-                .setHeader4RelativeSize(1.15f)
-                .setHeader5RelativeSize(1.1f)
-                .setHeader6RelativeSize(1.05f)
-                .setHorizontalRulesHeight(2)
-                .setLinkFontColor(ContextCompat.getColor(context, R.color.primary));
-    }
-
-    public static Builder getMarkDownConfiguration(Context context, Boolean darkTheme) {
-        return new Builder(context)
-                .setHeader2RelativeSize(1.35f)
-                .setHeader3RelativeSize(1.25f)
-                .setHeader4RelativeSize(1.15f)
-                .setHeader5RelativeSize(1.1f)
-                .setHeader6RelativeSize(1.05f)
-                .setHorizontalRulesHeight(2)
-                .setLinkFontColor(ResourcesCompat.getColor(context.getResources(), R.color.primary, null));
-    }
-}
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 c2ba6f46a..d11631fde 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
@@ -5,7 +5,6 @@ import android.content.res.Resources;
 import android.graphics.Typeface;
 import android.text.Spannable;
 import android.text.SpannableString;
-import android.text.SpannableStringBuilder;
 import android.text.Spanned;
 import android.text.method.LinkMovementMethod;
 import android.text.style.ForegroundColorSpan;
@@ -42,9 +41,9 @@ public class SpannableUtil {
     public static void setTextWithURL(@NonNull TextView textView, @NonNull Resources resources, @StringRes int containerTextId, @StringRes int linkLabelId, @StringRes int urlId) {
         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);
+        final SpannableString finalSpannable = new SpannableString(finalText);
+        finalSpannable.setSpan(new URLSpan(resources.getString(urlId)), finalText.indexOf(linkLabel), finalText.indexOf(linkLabel) + linkLabel.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+        textView.setText(finalSpannable);
         textView.setMovementMethod(new LinkMovementMethod());
     }
 }
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 fbc7fc3fc..d90ce297c 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
@@ -2,12 +2,8 @@ package it.niedermann.nextcloud.deck.util;
 
 import android.content.Context;
 import android.content.res.ColorStateList;
-import android.graphics.Bitmap;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
-import android.text.Spannable;
-import android.text.SpannableStringBuilder;
-import android.text.style.ImageSpan;
 import android.widget.ImageView;
 import android.widget.TextView;
 
@@ -15,7 +11,6 @@ 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;
@@ -23,19 +18,12 @@ import androidx.core.widget.TextViewCompat;
 
 import com.bumptech.glide.Glide;
 import com.bumptech.glide.request.RequestOptions;
-import com.bumptech.glide.request.target.CustomTarget;
-import com.bumptech.glide.request.transition.Transition;
 
 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;
 
@@ -88,63 +76,7 @@ public final class ViewUtil {
         return drawable;
     }
 
-    /**
-     * Replaces all mentions in the textView with an avatar and the display name
-     *
-     * @param account  {@link Account} where the users of those mentions belong to
-     * @param mentions {@link List} of all mentions that should be substituted
-     * @param textView target {@link TextView}
-     */
-    public static void setupMentions(@NonNull Account account, @NonNull List<Mention> mentions, TextView textView) {
-        Context context = textView.getContext();
-        SpannableStringBuilder messageBuilder = new SpannableStringBuilder(textView.getText());
-
-        // Step 1
-        // Add avatar icons and display names
-        for (Mention m : mentions) {
-            final String mentionId = "@" + m.getMentionId();
-            final String mentionDisplayName = " " + m.getMentionDisplayName();
-            int index = messageBuilder.toString().lastIndexOf(mentionId);
-            while (index >= 0) {
-                messageBuilder.setSpan(new ImageSpan(context, R.drawable.ic_person_grey600_24dp), index, index + mentionId.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
-                messageBuilder.insert(index + mentionId.length(), mentionDisplayName);
-                index = messageBuilder.toString().substring(0, index).lastIndexOf(mentionId);
-            }
-        }
-        textView.setText(messageBuilder);
-
-        // Step 2
-        // Replace avatar icons with real avatars
-        final ImageSpan[] list = messageBuilder.getSpans(0, messageBuilder.length(), ImageSpan.class);
-        for (ImageSpan span : list) {
-            final int spanStart = messageBuilder.getSpanStart(span);
-            final int spanEnd = messageBuilder.getSpanEnd(span);
-            Glide.with(context)
-                    .asBitmap()
-                    .placeholder(R.drawable.ic_person_grey600_24dp)
-                    .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
-                        public void onResourceReady(@NonNull Bitmap resource, @Nullable Transition<? super Bitmap> transition) {
-                            messageBuilder.removeSpan(span);
-                            messageBuilder.setSpan(new ImageSpan(context, resource), spanStart, spanEnd, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
-                        }
-
-                        @Override
-                        public void onLoadCleared(@Nullable Drawable placeholder) {
-                            // silence is gold
-                        }
-                    });
-        }
-        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));
-        }
+        imageView.setImageTintList(ColorStateList.valueOf(ContextCompat.getColor(context, colorRes)));
     }
 }