Merge branch 'master' into patch-2

63 files changed, 1864 insertions, 770 deletions

diff --git a/apps/dav/lib/AppInfo/Application.php b/apps/dav/lib/AppInfo/Application.php
index 580918a6450..86749862626 100644
--- a/apps/dav/lib/AppInfo/Application.php
+++ b/apps/dav/lib/AppInfo/Application.php
@@ -35,18 +35,14 @@ namespace OCA\DAV\AppInfo;
 use Exception;
 use OCA\DAV\BackgroundJob\UpdateCalendarResourcesRoomsBackgroundJob;
 use OCA\DAV\CalDAV\Activity\Backend;
-use OCA\DAV\CalDAV\BirthdayService;
-use OCA\DAV\CalDAV\CalDavBackend;
 use OCA\DAV\CalDAV\CalendarManager;
 use OCA\DAV\CalDAV\CalendarProvider;
-use OCA\DAV\CalDAV\Reminder\Backend as ReminderBackend;
 use OCA\DAV\CalDAV\Reminder\NotificationProvider\AudioProvider;
 use OCA\DAV\CalDAV\Reminder\NotificationProvider\EmailProvider;
 use OCA\DAV\CalDAV\Reminder\NotificationProvider\PushProvider;
 use OCA\DAV\CalDAV\Reminder\NotificationProviderManager;
 use OCA\DAV\CalDAV\Reminder\Notifier;
 
-use OCA\DAV\CalDAV\WebcalCaching\RefreshWebcalService;
 use OCA\DAV\Capabilities;
 use OCA\DAV\CardDAV\CardDavBackend;
 use OCA\DAV\CardDAV\ContactsManager;
@@ -61,22 +57,35 @@ use OCA\DAV\Events\CalendarDeletedEvent;
 use OCA\DAV\Events\CalendarMovedToTrashEvent;
 use OCA\DAV\Events\CalendarObjectCreatedEvent;
 use OCA\DAV\Events\CalendarObjectDeletedEvent;
+use OCA\DAV\Events\CalendarObjectMovedEvent;
 use OCA\DAV\Events\CalendarObjectMovedToTrashEvent;
 use OCA\DAV\Events\CalendarObjectRestoredEvent;
 use OCA\DAV\Events\CalendarObjectUpdatedEvent;
+use OCA\DAV\Events\CalendarPublishedEvent;
 use OCA\DAV\Events\CalendarRestoredEvent;
 use OCA\DAV\Events\CalendarShareUpdatedEvent;
+use OCA\DAV\Events\CalendarUnpublishedEvent;
 use OCA\DAV\Events\CalendarUpdatedEvent;
 use OCA\DAV\Events\CardCreatedEvent;
 use OCA\DAV\Events\CardDeletedEvent;
 use OCA\DAV\Events\CardUpdatedEvent;
+use OCA\DAV\Events\SubscriptionCreatedEvent;
+use OCA\DAV\Events\SubscriptionDeletedEvent;
+use OCP\Federation\Events\TrustedServerRemovedEvent;
 use OCA\DAV\HookManager;
 use OCA\DAV\Listener\ActivityUpdaterListener;
 use OCA\DAV\Listener\AddressbookListener;
+use OCA\DAV\Listener\BirthdayListener;
 use OCA\DAV\Listener\CalendarContactInteractionListener;
 use OCA\DAV\Listener\CalendarDeletionDefaultUpdaterListener;
 use OCA\DAV\Listener\CalendarObjectReminderUpdaterListener;
+use OCA\DAV\Listener\CalendarPublicationListener;
+use OCA\DAV\Listener\CalendarShareUpdateListener;
 use OCA\DAV\Listener\CardListener;
+use OCA\DAV\Listener\ClearPhotoCacheListener;
+use OCA\DAV\Listener\SubscriptionListener;
+use OCA\DAV\Listener\TrustedServerRemovedListener;
+use OCA\DAV\Listener\UserPreferenceListener;
 use OCA\DAV\Search\ContactsSearchProvider;
 use OCA\DAV\Search\EventsSearchProvider;
 use OCA\DAV\Search\TasksSearchProvider;
@@ -88,6 +97,8 @@ use OCP\AppFramework\Bootstrap\IBootstrap;
 use OCP\AppFramework\Bootstrap\IRegistrationContext;
 use OCP\AppFramework\IAppContainer;
 use OCP\Calendar\IManager as ICalendarManager;
+use OCP\Config\BeforePreferenceDeletedEvent;
+use OCP\Config\BeforePreferenceSetEvent;
 use OCP\Contacts\IManager as IContactsManager;
 use OCP\IServerContainer;
 use OCP\IUser;
@@ -149,11 +160,19 @@ class Application extends App implements IBootstrap {
 		$context->registerEventListener(CalendarObjectUpdatedEvent::class, CalendarObjectReminderUpdaterListener::class);
 		$context->registerEventListener(CalendarObjectDeletedEvent::class, ActivityUpdaterListener::class);
 		$context->registerEventListener(CalendarObjectDeletedEvent::class, CalendarObjectReminderUpdaterListener::class);
+		$context->registerEventListener(CalendarObjectMovedEvent::class, ActivityUpdaterListener::class);
+		$context->registerEventListener(CalendarObjectMovedEvent::class, CalendarObjectReminderUpdaterListener::class);
 		$context->registerEventListener(CalendarObjectMovedToTrashEvent::class, ActivityUpdaterListener::class);
 		$context->registerEventListener(CalendarObjectMovedToTrashEvent::class, CalendarObjectReminderUpdaterListener::class);
 		$context->registerEventListener(CalendarObjectRestoredEvent::class, ActivityUpdaterListener::class);
 		$context->registerEventListener(CalendarObjectRestoredEvent::class, CalendarObjectReminderUpdaterListener::class);
 		$context->registerEventListener(CalendarShareUpdatedEvent::class, CalendarContactInteractionListener::class);
+		$context->registerEventListener(CalendarPublishedEvent::class, CalendarPublicationListener::class);
+		$context->registerEventListener(CalendarUnpublishedEvent::class, CalendarPublicationListener::class);
+		$context->registerEventListener(CalendarShareUpdatedEvent::class, CalendarShareUpdateListener::class);
+
+		$context->registerEventListener(SubscriptionCreatedEvent::class, SubscriptionListener::class);
+		$context->registerEventListener(SubscriptionDeletedEvent::class, SubscriptionListener::class);
 
 
 		$context->registerEventListener(AddressBookCreatedEvent::class, AddressbookListener::class);
@@ -163,6 +182,15 @@ class Application extends App implements IBootstrap {
 		$context->registerEventListener(CardCreatedEvent::class, CardListener::class);
 		$context->registerEventListener(CardDeletedEvent::class, CardListener::class);
 		$context->registerEventListener(CardUpdatedEvent::class, CardListener::class);
+		$context->registerEventListener(CardCreatedEvent::class, BirthdayListener::class);
+		$context->registerEventListener(CardDeletedEvent::class, BirthdayListener::class);
+		$context->registerEventListener(CardUpdatedEvent::class, BirthdayListener::class);
+		$context->registerEventListener(CardDeletedEvent::class, ClearPhotoCacheListener::class);
+		$context->registerEventListener(CardUpdatedEvent::class, ClearPhotoCacheListener::class);
+		$context->registerEventListener(TrustedServerRemovedEvent::class, TrustedServerRemovedListener::class);
+
+		$context->registerEventListener(BeforePreferenceDeletedEvent::class, UserPreferenceListener::class);
+		$context->registerEventListener(BeforePreferenceSetEvent::class, UserPreferenceListener::class);
 
 		$context->registerNotifierService(Notifier::class);
 
@@ -195,44 +223,6 @@ class Application extends App implements IBootstrap {
 			}
 		});
 
-		$birthdayListener = function ($event) use ($container): void {
-			if ($event instanceof GenericEvent) {
-				/** @var BirthdayService $b */
-				$b = $container->query(BirthdayService::class);
-				$b->onCardChanged(
-					(int) $event->getArgument('addressBookId'),
-					(string) $event->getArgument('cardUri'),
-					(string) $event->getArgument('cardData')
-				);
-			}
-		};
-
-		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::createCard', $birthdayListener);
-		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::updateCard', $birthdayListener);
-		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::deleteCard', function ($event) use ($container) {
-			if ($event instanceof GenericEvent) {
-				/** @var BirthdayService $b */
-				$b = $container->query(BirthdayService::class);
-				$b->onCardDeleted(
-					(int) $event->getArgument('addressBookId'),
-					(string) $event->getArgument('cardUri')
-				);
-			}
-		});
-
-		$clearPhotoCache = function ($event) use ($container): void {
-			if ($event instanceof GenericEvent) {
-				/** @var PhotoCache $p */
-				$p = $container->query(PhotoCache::class);
-				$p->delete(
-					$event->getArgument('addressBookId'),
-					$event->getArgument('cardUri')
-				);
-			}
-		};
-		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::updateCard', $clearPhotoCache);
-		$dispatcher->addListener('\OCA\DAV\CardDAV\CardDavBackend::deleteCard', $clearPhotoCache);
-
 		$dispatcher->addListener('OC\AccountManager::userUpdated', function (GenericEvent $event) use ($container) {
 			$user = $event->getSubject();
 			/** @var SyncService $syncService */
@@ -254,70 +244,6 @@ class Application extends App implements IBootstrap {
 			// Here we should recalculate if reminders should be sent to new or old sharees
 		});
 
-		$dispatcher->addListener('\OCA\DAV\CalDAV\CalDavBackend::publishCalendar', function (GenericEvent $event) use ($container) {
-			/** @var Backend $backend */
-			$backend = $container->query(Backend::class);
-			$backend->onCalendarPublication(
-				$event->getArgument('calendarData'),
-				$event->getArgument('public')
-			);
-		});
-
-
-		$dispatcher->addListener('OCP\Federation\TrustedServerEvent::remove',
-			function (GenericEvent $event) {
-				/** @var CardDavBackend $cardDavBackend */
-				$cardDavBackend = \OC::$server->query(CardDavBackend::class);
-				$addressBookUri = $event->getSubject();
-				$addressBook = $cardDavBackend->getAddressBooksByUri('principals/system/system', $addressBookUri);
-				if (!is_null($addressBook)) {
-					$cardDavBackend->deleteAddressBook($addressBook['id']);
-				}
-			}
-		);
-
-		$dispatcher->addListener('\OCA\DAV\CalDAV\CalDavBackend::createSubscription',
-			function (GenericEvent $event) use ($container, $serverContainer) {
-				$jobList = $serverContainer->getJobList();
-				$subscriptionData = $event->getArgument('subscriptionData');
-
-				/**
-				 * Initial subscription refetch
-				 *
-				 * @var RefreshWebcalService $refreshWebcalService
-				 */
-				$refreshWebcalService = $container->query(RefreshWebcalService::class);
-				$refreshWebcalService->refreshSubscription(
-					(string) $subscriptionData['principaluri'],
-					(string) $subscriptionData['uri']
-				);
-
-				$jobList->add(\OCA\DAV\BackgroundJob\RefreshWebcalJob::class, [
-					'principaluri' => $subscriptionData['principaluri'],
-					'uri' => $subscriptionData['uri']
-				]);
-			}
-		);
-
-		$dispatcher->addListener('\OCA\DAV\CalDAV\CalDavBackend::deleteSubscription',
-			function (GenericEvent $event) use ($container, $serverContainer) {
-				$jobList = $serverContainer->getJobList();
-				$subscriptionData = $event->getArgument('subscriptionData');
-
-				$jobList->remove(\OCA\DAV\BackgroundJob\RefreshWebcalJob::class, [
-					'principaluri' => $subscriptionData['principaluri'],
-					'uri' => $subscriptionData['uri']
-				]);
-
-				/** @var CalDavBackend $calDavBackend */
-				$calDavBackend = $container->get(CalDavBackend::class);
-				$calDavBackend->purgeAllCachedEventsForSubscription($subscriptionData['id']);
-				/** @var ReminderBackend $calDavBackend */
-				$reminderBackend = $container->get(ReminderBackend::class);
-				$reminderBackend->cleanRemindersForCalendar((int) $subscriptionData['id']);
-			}
-		);
-
 		$eventHandler = function () use ($container, $serverContainer): void {
 			try {
 				/** @var UpdateCalendarResourcesRoomsBackgroundJob $job */
diff --git a/apps/dav/lib/BackgroundJob/UploadCleanup.php b/apps/dav/lib/BackgroundJob/UploadCleanup.php
index f612f58cd7c..3a6f296deaf 100644
--- a/apps/dav/lib/BackgroundJob/UploadCleanup.php
+++ b/apps/dav/lib/BackgroundJob/UploadCleanup.php
@@ -37,15 +37,18 @@ use OCP\Files\File;
 use OCP\Files\Folder;
 use OCP\Files\IRootFolder;
 use OCP\Files\NotFoundException;
+use Psr\Log\LoggerInterface;
 
 class UploadCleanup extends TimedJob {
 	private IRootFolder $rootFolder;
 	private IJobList $jobList;
+	private LoggerInterface $logger;
 
-	public function __construct(ITimeFactory $time, IRootFolder $rootFolder, IJobList $jobList) {
+	public function __construct(ITimeFactory $time, IRootFolder $rootFolder, IJobList $jobList, LoggerInterface $logger) {
 		parent::__construct($time);
 		$this->rootFolder = $rootFolder;
 		$this->jobList = $jobList;
+		$this->logger = $logger;
 
 		// Run once a day
 		$this->setInterval(60 * 60 * 24);
@@ -61,19 +64,27 @@ class UploadCleanup extends TimedJob {
 			$userRoot = $userFolder->getParent();
 			/** @var Folder $uploads */
 			$uploads = $userRoot->get('uploads');
-			/** @var Folder $uploadFolder */
 			$uploadFolder = $uploads->get($folder);
 		} catch (NotFoundException | NoUserException $e) {
 			$this->jobList->remove(self::class, $argument);
 			return;
 		}
 
-		/** @var File[] $files */
-		$files = $uploadFolder->getDirectoryListing();
-
 		// Remove if all files have an mtime of more than a day
 		$time = $this->time->getTime() - 60 * 60 * 24;
 
+		if (!($uploadFolder instanceof Folder)) {
+			$this->logger->error("Found a file inside the uploads folder. Uid: " . $uid . ' folder: ' . $folder);
+			if ($uploadFolder->getMTime() < $time) {
+				$uploadFolder->delete();
+			}
+			$this->jobList->remove(self::class, $argument);
+			return;
+		}
+
+		/** @var File[] $files */
+		$files = $uploadFolder->getDirectoryListing();
+
 		// The folder has to be more than a day old
 		$initial = $uploadFolder->getMTime() < $time;
 
diff --git a/apps/dav/lib/BackgroundJob/UserStatusAutomation.php b/apps/dav/lib/BackgroundJob/UserStatusAutomation.php
new file mode 100644
index 00000000000..bbd92d903ee
--- /dev/null
+++ b/apps/dav/lib/BackgroundJob/UserStatusAutomation.php
@@ -0,0 +1,188 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2022 Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\DAV\BackgroundJob;
+
+use OCA\DAV\CalDAV\Schedule\Plugin;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\IJobList;
+use OCP\BackgroundJob\TimedJob;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\IConfig;
+use OCP\IDBConnection;
+use OCP\UserStatus\IManager;
+use OCP\UserStatus\IUserStatus;
+use Psr\Log\LoggerInterface;
+use Sabre\VObject\Component\Available;
+use Sabre\VObject\Component\VAvailability;
+use Sabre\VObject\Reader;
+use Sabre\VObject\Recur\RRuleIterator;
+
+class UserStatusAutomation extends TimedJob {
+	protected IDBConnection $connection;
+	protected IJobList $jobList;
+	protected LoggerInterface $logger;
+	protected IManager $manager;
+	protected IConfig $config;
+
+	public function __construct(ITimeFactory $timeFactory,
+								IDBConnection $connection,
+								IJobList $jobList,
+								LoggerInterface $logger,
+								IManager $manager,
+								IConfig $config) {
+		parent::__construct($timeFactory);
+		$this->connection = $connection;
+		$this->jobList = $jobList;
+		$this->logger = $logger;
+		$this->manager = $manager;
+		$this->config = $config;
+
+		// Interval 0 might look weird, but the last_checked is always moved
+		// to the next time we need this and then it's 0 seconds ago.
+		$this->setInterval(0);
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	protected function run($argument) {
+		if (!isset($argument['userId'])) {
+			$this->jobList->remove(self::class, $argument);
+			$this->logger->info('Removing invalid ' . self::class . ' background job');
+			return;
+		}
+
+		$userId = $argument['userId'];
+		$automationEnabled = $this->config->getUserValue($userId, 'dav', 'user_status_automation', 'no') === 'yes';
+		if (!$automationEnabled) {
+			$this->logger->info('Removing ' . self::class . ' background job for user "' . $userId . '" because the setting is disabled');
+			$this->jobList->remove(self::class, $argument);
+			return;
+		}
+
+		$property = $this->getAvailabilityFromPropertiesTable($userId);
+
+		if (!$property) {
+			$this->logger->info('Removing ' . self::class . ' background job for user "' . $userId . '" because the user has no availability settings');
+			$this->jobList->remove(self::class, $argument);
+			return;
+		}
+
+		$isCurrentlyAvailable = false;
+		$nextPotentialToggles = [];
+
+		$now = new \DateTime('now');
+		$lastMidnight = (clone $now)->setTime(0, 0);
+
+		$vObject = Reader::read($property);
+		foreach ($vObject->getComponents() as $component) {
+			if ($component->name !== 'VAVAILABILITY') {
+				continue;
+			}
+			/** @var VAvailability $component */
+			$availables = $component->getComponents();
+			foreach ($availables as $available) {
+				/** @var Available $available */
+				if ($available->name === 'AVAILABLE') {
+					/** @var \DateTimeInterface $effectiveStart */
+					/** @var \DateTimeInterface $effectiveEnd */
+					[$effectiveStart, $effectiveEnd] = $available->getEffectiveStartEnd();
+
+					try {
+						$it = new RRuleIterator((string) $available->RRULE, $effectiveStart);
+						$it->fastForward($lastMidnight);
+
+						$startToday = $it->current();
+						if ($startToday && $startToday <= $now) {
+							$duration = $effectiveStart->diff($effectiveEnd);
+							$endToday = $startToday->add($duration);
+							if ($endToday > $now) {
+								// User is currently available
+								// Also queuing the end time as next status toggle
+								$isCurrentlyAvailable = true;
+								$nextPotentialToggles[] = $endToday->getTimestamp();
+							}
+
+							// Availability enabling already done for today,
+							// so jump to the next recurrence to find the next status toggle
+							$it->next();
+						}
+
+						if ($it->current()) {
+							$nextPotentialToggles[] = $it->current()->getTimestamp();
+						}
+					} catch (\Exception $e) {
+						$this->logger->error($e->getMessage(), ['exception' => $e]);
+					}
+				}
+			}
+		}
+
+		$nextAutomaticToggle = min($nextPotentialToggles);
+		$this->setLastRunToNextToggleTime($userId, $nextAutomaticToggle - 1);
+
+		if ($isCurrentlyAvailable) {
+			$this->manager->revertUserStatus($userId, IUserStatus::MESSAGE_AVAILABILITY, IUserStatus::DND);
+		} else {
+			// The DND status automation is more important than the "Away - In call" so we also restore that one if it exists.
+			$this->manager->revertUserStatus($userId, IUserStatus::MESSAGE_CALL, IUserStatus::AWAY);
+			$this->manager->setUserStatus($userId, IUserStatus::MESSAGE_AVAILABILITY, IUserStatus::DND, true);
+		}
+		$this->logger->debug('User status automation ran');
+	}
+
+	protected function setLastRunToNextToggleTime(string $userId, int $timestamp): void {
+		$query = $this->connection->getQueryBuilder();
+
+		$query->update('jobs')
+			->set('last_run', $query->createNamedParameter($timestamp, IQueryBuilder::PARAM_INT))
+			->where($query->expr()->eq('id', $query->createNamedParameter($this->getId(), IQueryBuilder::PARAM_INT)));
+		$query->executeStatement();
+
+		$this->logger->debug('Updated user status automation last_run to ' . $timestamp . ' for user ' . $userId);
+	}
+
+	/**
+	 * @param string $userId
+	 * @return false|string
+	 */
+	protected function getAvailabilityFromPropertiesTable(string $userId) {
+		$propertyPath = 'calendars/' . $userId . '/inbox';
+		$propertyName = '{' . Plugin::NS_CALDAV . '}calendar-availability';
+
+		$query = $this->connection->getQueryBuilder();
+		$query->select('propertyvalue')
+			->from('properties')
+			->where($query->expr()->eq('userid', $query->createNamedParameter($userId)))
+			->andWhere($query->expr()->eq('propertypath', $query->createNamedParameter($propertyPath)))
+			->where($query->expr()->eq('propertyname', $query->createNamedParameter($propertyName)))
+			->setMaxResults(1);
+
+		$result = $query->executeQuery();
+		$property = $result->fetchOne();
+		$result->closeCursor();
+
+		return $property;
+	}
+}
diff --git a/apps/dav/lib/CalDAV/Activity/Backend.php b/apps/dav/lib/CalDAV/Activity/Backend.php
index 84ba50b8c37..781a456b5b3 100644
--- a/apps/dav/lib/CalDAV/Activity/Backend.php
+++ b/apps/dav/lib/CalDAV/Activity/Backend.php
@@ -34,6 +34,7 @@ use OCP\App\IAppManager;
 use OCP\IGroup;
 use OCP\IGroupManager;
 use OCP\IUser;
+use OCP\IUserManager;
 use OCP\IUserSession;
 use Sabre\VObject\Reader;
 
@@ -56,11 +57,15 @@ class Backend {
 	/** @var IAppManager */
 	protected $appManager;
 
-	public function __construct(IActivityManager $activityManager, IGroupManager $groupManager, IUserSession $userSession, IAppManager $appManager) {
+	/** @var IUserManager */
+	protected $userManager;
+
+	public function __construct(IActivityManager $activityManager, IGroupManager $groupManager, IUserSession $userSession, IAppManager $appManager, IUserManager $userManager) {
 		$this->activityManager = $activityManager;
 		$this->groupManager = $groupManager;
 		$this->userSession = $userSession;
 		$this->appManager = $appManager;
+		$this->userManager = $userManager;
 	}
 
 	/**
@@ -119,7 +124,7 @@ class Backend {
 	 * @param array $calendarData
 	 * @param bool $publishStatus
 	 */
-	public function onCalendarPublication(array $calendarData, $publishStatus) {
+	public function onCalendarPublication(array $calendarData, bool $publishStatus): void {
 		$this->triggerCalendarActivity($publishStatus ? Calendar::SUBJECT_PUBLISH : Calendar::SUBJECT_UNPUBLISH, $calendarData);
 	}
 
@@ -165,6 +170,11 @@ class Backend {
 		}
 
 		foreach ($users as $user) {
+			if ($action === Calendar::SUBJECT_DELETE && !$this->userManager->userExists($user)) {
+				// Avoid creating calendar_delete activities for deleted users
+				continue;
+			}
+
 			$event->setAffectedUser($user)
 				->setSubject(
 					$user === $currentUser ? $action . '_self' : $action,
@@ -438,6 +448,11 @@ class Backend {
 
 		$classification = $objectData['classification'] ?? CalDavBackend::CLASSIFICATION_PUBLIC;
 		$object = $this->getObjectNameAndType($objectData);
+
+		if (!$object) {
+			return;
+		}
+
 		$action = $action . '_' . $object['type'];
 
 		if ($object['type'] === 'todo' && strpos($action, Event::SUBJECT_OBJECT_UPDATE) === 0 && $object['status'] === 'COMPLETED') {
@@ -494,8 +509,103 @@ class Backend {
 	}
 
 	/**
+	 * Creates activities when a calendar object was moved
+	 */
+	public function onMovedCalendarObject(array $sourceCalendarData, array $targetCalendarData, array $sourceShares, array $targetShares, array $objectData): void {
+		if (!isset($targetCalendarData['principaluri'])) {
+			return;
+		}
+
+		$sourcePrincipal = explode('/', $sourceCalendarData['principaluri']);
+		$sourceOwner = array_pop($sourcePrincipal);
+
+		$targetPrincipal = explode('/', $targetCalendarData['principaluri']);
+		$targetOwner = array_pop($targetPrincipal);
+
+		if ($sourceOwner !== $targetOwner) {
+			$this->onTouchCalendarObject(
+				Event::SUBJECT_OBJECT_DELETE,
+				$sourceCalendarData,
+				$sourceShares,
+				$objectData
+			);
+			$this->onTouchCalendarObject(
+				Event::SUBJECT_OBJECT_ADD,
+				$targetCalendarData,
+				$targetShares,
+				$objectData
+			);
+			return;
+		}
+
+		$currentUser = $this->userSession->getUser();
+		if ($currentUser instanceof IUser) {
+			$currentUser = $currentUser->getUID();
+		} else {
+			$currentUser = $targetOwner;
+		}
+
+		$classification = $objectData['classification'] ?? CalDavBackend::CLASSIFICATION_PUBLIC;
+		$object = $this->getObjectNameAndType($objectData);
+
+		if (!$object) {
+			return;
+		}
+
+		$event = $this->activityManager->generateEvent();
+		$event->setApp('dav')
+			->setObject('calendar', (int) $targetCalendarData['id'])
+			->setType($object['type'] === 'event' ? 'calendar_event' : 'calendar_todo')
+			->setAuthor($currentUser);
+
+		$users = $this->getUsersForShares(array_intersect($sourceShares, $targetShares));
+		$users[] = $targetOwner;
+
+		// Users for share can return the owner itself if the calendar is published
+		foreach (array_unique($users) as $user) {
+			if ($classification === CalDavBackend::CLASSIFICATION_PRIVATE && $user !== $targetOwner) {
+				// Private events are only shown to the owner
+				continue;
+			}
+
+			$params = [
+				'actor' => $event->getAuthor(),
+				'sourceCalendar' => [
+					'id' => (int) $sourceCalendarData['id'],
+					'uri' => $sourceCalendarData['uri'],
+					'name' => $sourceCalendarData['{DAV:}displayname'],
+				],
+				'targetCalendar' => [
+					'id' => (int) $targetCalendarData['id'],
+					'uri' => $targetCalendarData['uri'],
+					'name' => $targetCalendarData['{DAV:}displayname'],
+				],
+				'object' => [
+					'id' => $object['id'],
+					'name' => $classification === CalDavBackend::CLASSIFICATION_CONFIDENTIAL && $user !== $targetOwner ? 'Busy' : $object['name'],
+					'classified' => $classification === CalDavBackend::CLASSIFICATION_CONFIDENTIAL && $user !== $targetOwner,
+				],
+			];
+
+			if ($object['type'] === 'event' && $this->appManager->isEnabledForUser('calendar')) {
+				$params['object']['link']['object_uri'] = $objectData['uri'];
+				$params['object']['link']['calendar_uri'] = $targetCalendarData['uri'];
+				$params['object']['link']['owner'] = $targetOwner;
+			}
+
+			$event->setAffectedUser($user)
+				->setSubject(
+					$user === $currentUser ? Event::SUBJECT_OBJECT_MOVE . '_' . $object['type'] . '_self' : Event::SUBJECT_OBJECT_MOVE . '_' . $object['type'],
+					$params
+				);
+
+			$this->activityManager->publish($event);
+		}
+	}
+
+	/**
 	 * @param array $objectData
-	 * @return string[]|bool
+	 * @return string[]|false
 	 */
 	protected function getObjectNameAndType(array $objectData) {
 		$vObject = Reader::read($objectData['calendardata']);
diff --git a/apps/dav/lib/CalDAV/Activity/Filter/Todo.php b/apps/dav/lib/CalDAV/Activity/Filter/Todo.php
index f727c10befe..6f1dbbdcb5c 100644
--- a/apps/dav/lib/CalDAV/Activity/Filter/Todo.php
+++ b/apps/dav/lib/CalDAV/Activity/Filter/Todo.php
@@ -52,7 +52,7 @@ class Todo implements IFilter {
 	 * @since 11.0.0
 	 */
 	public function getName() {
-		return $this->l->t('Todos');
+		return $this->l->t('To-dos');
 	}
 
 	/**
diff --git a/apps/dav/lib/CalDAV/Activity/Provider/Event.php b/apps/dav/lib/CalDAV/Activity/Provider/Event.php
index 3ed591219af..9ae04aadbba 100644
--- a/apps/dav/lib/CalDAV/Activity/Provider/Event.php
+++ b/apps/dav/lib/CalDAV/Activity/Provider/Event.php
@@ -40,6 +40,7 @@ use OCP\L10N\IFactory;
 class Event extends Base {
 	public const SUBJECT_OBJECT_ADD = 'object_add';
 	public const SUBJECT_OBJECT_UPDATE = 'object_update';
+	public const SUBJECT_OBJECT_MOVE = 'object_move';
 	public const SUBJECT_OBJECT_MOVE_TO_TRASH = 'object_move_to_trash';
 	public const SUBJECT_OBJECT_RESTORE = 'object_restore';
 	public const SUBJECT_OBJECT_DELETE = 'object_delete';
@@ -145,6 +146,10 @@ class Event extends Base {
 			$subject = $this->l->t('{actor} updated event {event} in calendar {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_UPDATE . '_event_self') {
 			$subject = $this->l->t('You updated event {event} in calendar {calendar}');
+		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_MOVE . '_event') {
+			$subject = $this->l->t('{actor} moved event {event} from calendar {sourceCalendar} to calendar {targetCalendar}');
+		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_MOVE . '_event_self') {
+			$subject = $this->l->t('You moved event {event} from calendar {sourceCalendar} to calendar {targetCalendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_MOVE_TO_TRASH . '_event') {
 			$subject = $this->l->t('{actor} deleted event {event} from calendar {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_MOVE_TO_TRASH . '_event_self') {
@@ -198,6 +203,24 @@ class Event extends Base {
 			}
 		}
 
+		if (isset($parameters['sourceCalendar']) && isset($parameters['targetCalendar'])) {
+			switch ($subject) {
+				case self::SUBJECT_OBJECT_MOVE . '_event':
+					return [
+						'actor' => $this->generateUserParameter($parameters['actor']),
+						'sourceCalendar' => $this->generateCalendarParameter($parameters['sourceCalendar'], $this->l),
+						'targetCalendar' => $this->generateCalendarParameter($parameters['targetCalendar'], $this->l),
+						'event' => $this->generateClassifiedObjectParameter($parameters['object']),
+					];
+				case self::SUBJECT_OBJECT_MOVE . '_event_self':
+					return [
+						'sourceCalendar' => $this->generateCalendarParameter($parameters['sourceCalendar'], $this->l),
+						'targetCalendar' => $this->generateCalendarParameter($parameters['targetCalendar'], $this->l),
+						'event' => $this->generateClassifiedObjectParameter($parameters['object']),
+					];
+			}
+		}
+
 		// Legacy - Do NOT Remove unless necessary
 		// Removing this will break parsing of activities that were created on
 		// Nextcloud 12, so we should keep this as long as it's acceptable.
diff --git a/apps/dav/lib/CalDAV/Activity/Provider/Todo.php b/apps/dav/lib/CalDAV/Activity/Provider/Todo.php
index a3ab81e38ae..e2ddb99a1af 100644
--- a/apps/dav/lib/CalDAV/Activity/Provider/Todo.php
+++ b/apps/dav/lib/CalDAV/Activity/Provider/Todo.php
@@ -50,25 +50,29 @@ class Todo extends Event {
 		}
 
 		if ($event->getSubject() === self::SUBJECT_OBJECT_ADD . '_todo') {
-			$subject = $this->l->t('{actor} created todo {todo} in list {calendar}');
+			$subject = $this->l->t('{actor} created to-do {todo} in list {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_ADD . '_todo_self') {
-			$subject = $this->l->t('You created todo {todo} in list {calendar}');
+			$subject = $this->l->t('You created to-do {todo} in list {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_DELETE . '_todo') {
-			$subject = $this->l->t('{actor} deleted todo {todo} from list {calendar}');
+			$subject = $this->l->t('{actor} deleted to-do {todo} from list {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_DELETE . '_todo_self') {
-			$subject = $this->l->t('You deleted todo {todo} from list {calendar}');
+			$subject = $this->l->t('You deleted to-do {todo} from list {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_UPDATE . '_todo') {
-			$subject = $this->l->t('{actor} updated todo {todo} in list {calendar}');
+			$subject = $this->l->t('{actor} updated to-do {todo} in list {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_UPDATE . '_todo_self') {
-			$subject = $this->l->t('You updated todo {todo} in list {calendar}');
+			$subject = $this->l->t('You updated to-do {todo} in list {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_UPDATE . '_todo_completed') {
-			$subject = $this->l->t('{actor} solved todo {todo} in list {calendar}');
+			$subject = $this->l->t('{actor} solved to-do {todo} in list {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_UPDATE . '_todo_completed_self') {
-			$subject = $this->l->t('You solved todo {todo} in list {calendar}');
+			$subject = $this->l->t('You solved to-do {todo} in list {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_UPDATE . '_todo_needs_action') {
-			$subject = $this->l->t('{actor} reopened todo {todo} in list {calendar}');
+			$subject = $this->l->t('{actor} reopened to-do {todo} in list {calendar}');
 		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_UPDATE . '_todo_needs_action_self') {
-			$subject = $this->l->t('You reopened todo {todo} in list {calendar}');
+			$subject = $this->l->t('You reopened to-do {todo} in list {calendar}');
+		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_MOVE . '_todo') {
+			$subject = $this->l->t('{actor} moved to-do {todo} from list {sourceCalendar} to list {targetCalendar}');
+		} elseif ($event->getSubject() === self::SUBJECT_OBJECT_MOVE . '_todo_self') {
+			$subject = $this->l->t('You moved to-do {todo} from list {sourceCalendar} to list {targetCalendar}');
 		} else {
 			throw new \InvalidArgumentException();
 		}
@@ -114,6 +118,24 @@ class Todo extends Event {
 			}
 		}
 
+		if (isset($parameters['sourceCalendar']) && isset($parameters['targetCalendar'])) {
+			switch ($subject) {
+				case self::SUBJECT_OBJECT_MOVE . '_todo':
+					return [
+						'actor' => $this->generateUserParameter($parameters['actor']),
+						'sourceCalendar' => $this->generateCalendarParameter($parameters['sourceCalendar'], $this->l),
+						'targetCalendar' => $this->generateCalendarParameter($parameters['targetCalendar'], $this->l),
+						'todo' => $this->generateObjectParameter($parameters['object']),
+					];
+				case self::SUBJECT_OBJECT_MOVE . '_todo_self':
+					return [
+						'sourceCalendar' => $this->generateCalendarParameter($parameters['sourceCalendar'], $this->l),
+						'targetCalendar' => $this->generateCalendarParameter($parameters['targetCalendar'], $this->l),
+						'todo' => $this->generateObjectParameter($parameters['object']),
+					];
+			}
+		}
+
 		// Legacy - Do NOT Remove unless necessary
 		// Removing this will break parsing of activities that were created on
 		// Nextcloud 12, so we should keep this as long as it's acceptable.
diff --git a/apps/dav/lib/CalDAV/Activity/Setting/Todo.php b/apps/dav/lib/CalDAV/Activity/Setting/Todo.php
index 7d27b30c4af..a4ac3f5d569 100644
--- a/apps/dav/lib/CalDAV/Activity/Setting/Todo.php
+++ b/apps/dav/lib/CalDAV/Activity/Setting/Todo.php
@@ -38,7 +38,7 @@ class Todo extends CalDAVSetting {
 	 * @since 11.0.0
 	 */
 	public function getName() {
-		return $this->l->t('A calendar <strong>todo</strong> was modified');
+		return $this->l->t('A calendar <strong>to-do</strong> was modified');
 	}
 
 	/**
diff --git a/apps/dav/lib/CalDAV/BirthdayService.php b/apps/dav/lib/CalDAV/BirthdayService.php
index 1030768e26f..be6b0911538 100644
--- a/apps/dav/lib/CalDAV/BirthdayService.php
+++ b/apps/dav/lib/CalDAV/BirthdayService.php
@@ -14,6 +14,7 @@ declare(strict_types=1);
  * @author Sven Strickroth <email@cs-ware.de>
  * @author Thomas Müller <thomas.mueller@tmit.eu>
  * @author Valdnet <47037905+Valdnet@users.noreply.github.com>
+ * @author Cédric Neukom <github@webguy.ch>
  *
  * @license AGPL-3.0
  *
@@ -86,6 +87,9 @@ class BirthdayService {
 
 		$targetPrincipals = $this->getAllAffectedPrincipals($addressBookId);
 		$book = $this->cardDavBackEnd->getAddressBookById($addressBookId);
+		if ($book === null) {
+			return;
+		}
 		$targetPrincipals[] = $book['principaluri'];
 		$datesToSync = [
 			['postfix' => '', 'field' => 'BDAY'],
@@ -98,9 +102,14 @@ class BirthdayService {
 				continue;
 			}
 
+			$reminderOffset = $this->getReminderOffsetForUser($principalUri);
+
 			$calendar = $this->ensureCalendarExists($principalUri);
+			if ($calendar === null) {
+				return;
+			}
 			foreach ($datesToSync as $type) {
-				$this->updateCalendar($cardUri, $cardData, $book, (int) $calendar['id'], $type);
+				$this->updateCalendar($cardUri, $cardData, $book, (int) $calendar['id'], $type, $reminderOffset);
 			}
 		}
 	}
@@ -148,12 +157,14 @@ class BirthdayService {
 	 * @param $cardData
 	 * @param $dateField
 	 * @param $postfix
+	 * @param $reminderOffset
 	 * @return VCalendar|null
 	 * @throws InvalidDataException
 	 */
-	public function buildDateFromContact(string $cardData,
-										 string $dateField,
-										 string $postfix):?VCalendar {
+	public function buildDateFromContact(string  $cardData,
+										 string  $dateField,
+										 string  $postfix,
+										 ?string $reminderOffset):?VCalendar {
 		if (empty($cardData)) {
 			return null;
 		}
@@ -258,11 +269,13 @@ class BirthdayService {
 		if ($originalYear !== null) {
 			$vEvent->{'X-NEXTCLOUD-BC-YEAR'} = (string) $originalYear;
 		}
-		$alarm = $vCal->createComponent('VALARM');
-		$alarm->add($vCal->createProperty('TRIGGER', '-PT0M', ['VALUE' => 'DURATION']));
-		$alarm->add($vCal->createProperty('ACTION', 'DISPLAY'));
-		$alarm->add($vCal->createProperty('DESCRIPTION', $vEvent->{'SUMMARY'}));
-		$vEvent->add($alarm);
+		if ($reminderOffset) {
+			$alarm = $vCal->createComponent('VALARM');
+			$alarm->add($vCal->createProperty('TRIGGER', $reminderOffset, ['VALUE' => 'DURATION']));
+			$alarm->add($vCal->createProperty('ACTION', 'DISPLAY'));
+			$alarm->add($vCal->createProperty('DESCRIPTION', $vEvent->{'SUMMARY'}));
+			$vEvent->add($alarm);
+		}
 		$vCal->add($vEvent);
 		return $vCal;
 	}
@@ -273,6 +286,9 @@ class BirthdayService {
 	public function resetForUser(string $user):void {
 		$principal = 'principals/users/'.$user;
 		$calendar = $this->calDavBackEnd->getCalendarByUri($principal, self::BIRTHDAY_CALENDAR_URI);
+		if (!$calendar) {
+			return; // The user's birthday calendar doesn't exist, no need to purge it
+		}
 		$calendarObjects = $this->calDavBackEnd->getCalendarObjects($calendar['id'], CalDavBackend::CALENDAR_TYPE_CALENDAR);
 
 		foreach ($calendarObjects as $calendarObject) {
@@ -341,6 +357,7 @@ class BirthdayService {
 	 * @param array $book
 	 * @param int $calendarId
 	 * @param array $type
+	 * @param string $reminderOffset
 	 * @throws InvalidDataException
 	 * @throws \Sabre\DAV\Exception\BadRequest
 	 */
@@ -348,9 +365,10 @@ class BirthdayService {
 									string $cardData,
 									array $book,
 									int $calendarId,
-									array $type):void {
+									array $type,
+									?string $reminderOffset):void {
 		$objectUri = $book['uri'] . '-' . $cardUri . $type['postfix'] . '.ics';
-		$calendarData = $this->buildDateFromContact($cardData, $type['field'], $type['postfix']);
+		$calendarData = $this->buildDateFromContact($cardData, $type['field'], $type['postfix'], $reminderOffset);
 		$existing = $this->calDavBackEnd->getCalendarObject($calendarId, $objectUri);
 		if ($calendarData === null) {
 			if ($existing !== null) {
@@ -391,14 +409,27 @@ class BirthdayService {
 	}
 
 	/**
+	 * Extracts the userId part of a principal
+	 *
+	 * @param string $userPrincipal
+	 * @return string|null
+	 */
+	private function principalToUserId(string $userPrincipal):?string {
+		if (substr($userPrincipal, 0, 17) === 'principals/users/') {
+			return substr($userPrincipal, 17);
+		}
+		return null;
+	}
+
+	/**
 	 * Checks if the user opted-out of birthday calendars
 	 *
 	 * @param string $userPrincipal The user principal to check for
 	 * @return bool
 	 */
 	private function isUserEnabled(string $userPrincipal):bool {
-		if (strpos($userPrincipal, 'principals/users/') === 0) {
-			$userId = substr($userPrincipal, 17);
+		$userId = $this->principalToUserId($userPrincipal);
+		if ($userId !== null) {
 			$isEnabled = $this->config->getUserValue($userId, 'dav', 'generateBirthdayCalendar', 'yes');
 			return $isEnabled === 'yes';
 		}
@@ -408,6 +439,23 @@ class BirthdayService {
 	}
 
 	/**
+	 * Get the reminder offset value for a user. This is a duration string (e.g.
+	 * PT9H) or null if no reminder is wanted.
+	 *
+	 * @param string $userPrincipal
+	 * @return string|null
+	 */
+	private function getReminderOffsetForUser(string $userPrincipal):?string {
+		$userId = $this->principalToUserId($userPrincipal);
+		if ($userId !== null) {
+			return $this->config->getUserValue($userId, 'dav', 'birthdayCalendarReminderOffset', 'PT9H') ?: null;
+		}
+
+		// not sure how we got here, just be on the safe side and return the default value
+		return 'PT9H';
+	}
+
+	/**
 	 * Formats title of Birthday event
 	 *
 	 * @param string $field Field name like BDAY, ANNIVERSARY, ...
diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index 8bdc084cd7b..2bbdc51f42e 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -52,6 +52,7 @@ use OCA\DAV\Events\CalendarDeletedEvent;
 use OCA\DAV\Events\CalendarMovedToTrashEvent;
 use OCA\DAV\Events\CalendarObjectCreatedEvent;
 use OCA\DAV\Events\CalendarObjectDeletedEvent;
+use OCA\DAV\Events\CalendarObjectMovedEvent;
 use OCA\DAV\Events\CalendarObjectMovedToTrashEvent;
 use OCA\DAV\Events\CalendarObjectRestoredEvent;
 use OCA\DAV\Events\CalendarObjectUpdatedEvent;
@@ -95,8 +96,6 @@ use Sabre\VObject\ParseException;
 use Sabre\VObject\Property;
 use Sabre\VObject\Reader;
 use Sabre\VObject\Recur\EventIterator;
-use Symfony\Component\EventDispatcher\EventDispatcherInterface;
-use Symfony\Component\EventDispatcher\GenericEvent;
 use function array_column;
 use function array_merge;
 use function array_values;
@@ -150,7 +149,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	 * @var array
 	 * @psalm-var array<string, string[]>
 	 */
-	public $propertyMap = [
+	public array $propertyMap = [
 		'{DAV:}displayname' => ['displayname', 'string'],
 		'{urn:ietf:params:xml:ns:caldav}calendar-description' => ['description', 'string'],
 		'{urn:ietf:params:xml:ns:caldav}calendar-timezone' => ['timezone', 'string'],
@@ -164,7 +163,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	 *
 	 * @var array
 	 */
-	public $subscriptionPropertyMap = [
+	public array $subscriptionPropertyMap = [
 		'{DAV:}displayname' => ['displayname', 'string'],
 		'{http://apple.com/ns/ical/}refreshrate' => ['refreshrate', 'string'],
 		'{http://apple.com/ns/ical/}calendar-order' => ['calendarorder', 'int'],
@@ -195,7 +194,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	];
 
 	/** @var array parameters to index */
-	public static $indexParameters = [
+	public static array $indexParameters = [
 		'ATTENDEE' => ['CN'],
 		'ORGANIZER' => ['CN'],
 	];
@@ -203,43 +202,19 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	/**
 	 * @var string[] Map of uid => display name
 	 */
-	protected $userDisplayNames;
-
-	/** @var IDBConnection */
-	private $db;
-
-	/** @var Backend */
-	private $calendarSharingBackend;
-
-	/** @var Principal */
-	private $principalBackend;
-
-	/** @var IUserManager */
-	private $userManager;
-
-	/** @var ISecureRandom */
-	private $random;
+	protected array $userDisplayNames;
 
+	private IDBConnection $db;
+	private Backend $calendarSharingBackend;
+	private Principal $principalBackend;
+	private IUserManager $userManager;
+	private ISecureRandom $random;
 	private LoggerInterface $logger;
+	private IEventDispatcher $dispatcher;
+	private IConfig $config;
+	private bool $legacyEndpoint;
+	private string $dbObjectPropertiesTable = 'calendarobjects_props';
 
-	/** @var IEventDispatcher */
-	private $dispatcher;
-
-	/** @var EventDispatcherInterface */
-	private $legacyDispatcher;
-
-	/** @var IConfig */
-	private $config;
-
-	/** @var bool */
-	private $legacyEndpoint;
-
-	/** @var string */
-	private $dbObjectPropertiesTable = 'calendarobjects_props';
-
-	/**
-	 * CalDavBackend constructor.
-	 */
 	public function __construct(IDBConnection $db,
 								Principal $principalBackend,
 								IUserManager $userManager,
@@ -247,7 +222,6 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 								ISecureRandom $random,
 								LoggerInterface $logger,
 								IEventDispatcher $dispatcher,
-								EventDispatcherInterface $legacyDispatcher,
 								IConfig $config,
 								bool $legacyEndpoint = false) {
 		$this->db = $db;
@@ -257,7 +231,6 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 		$this->random = $random;
 		$this->logger = $logger;
 		$this->dispatcher = $dispatcher;
-		$this->legacyDispatcher = $legacyDispatcher;
 		$this->config = $config;
 		$this->legacyEndpoint = $legacyEndpoint;
 	}
@@ -701,10 +674,9 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	}
 
 	/**
-	 * @param $calendarId
-	 * @return array|null
+	 * @return array{id: int, uri: string, '{http://calendarserver.org/ns/}getctag': string, '{http://sabredav.org/ns}sync-token': int, '{urn:ietf:params:xml:ns:caldav}supported-calendar-component-set': SupportedCalendarComponentSet, '{urn:ietf:params:xml:ns:caldav}schedule-calendar-transp': ScheduleCalendarTransp }|null
 	 */
-	public function getCalendarById($calendarId) {
+	public function getCalendarById(int $calendarId): ?array {
 		$fields = array_column($this->propertyMap, 0);
 		$fields[] = 'id';
 		$fields[] = 'uri';
@@ -737,7 +709,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 			'uri' => $row['uri'],
 			'principaluri' => $this->convertPrincipal($row['principaluri'], !$this->legacyEndpoint),
 			'{' . Plugin::NS_CALENDARSERVER . '}getctag' => 'http://sabre.io/ns/sync/' . ($row['synctoken']?$row['synctoken']:'0'),
-			'{http://sabredav.org/ns}sync-token' => $row['synctoken']?$row['synctoken']:'0',
+			'{http://sabredav.org/ns}sync-token' => $row['synctoken'] ?? 0,
 			'{' . Plugin::NS_CALDAV . '}supported-calendar-component-set' => new SupportedCalendarComponentSet($components),
 			'{' . Plugin::NS_CALDAV . '}schedule-calendar-transp' => new ScheduleCalendarTransp($row['transparent']?'transparent':'opaque'),
 		];
@@ -893,7 +865,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 
 			$calendarData = $this->getCalendarById($calendarId);
 			$shares = $this->getShares($calendarId);
-			$this->dispatcher->dispatchTyped(new CalendarUpdatedEvent((int)$calendarId, $calendarData, $shares, $mutations));
+			$this->dispatcher->dispatchTyped(new CalendarUpdatedEvent($calendarId, $calendarData, $shares, $mutations));
 
 			return true;
 		});
@@ -943,7 +915,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 
 			// Only dispatch if we actually deleted anything
 			if ($calendarData) {
-				$this->dispatcher->dispatchTyped(new CalendarDeletedEvent((int)$calendarId, $calendarData, $shares));
+				$this->dispatcher->dispatchTyped(new CalendarDeletedEvent($calendarId, $calendarData, $shares));
 			}
 		} else {
 			$qbMarkCalendarDeleted = $this->db->getQueryBuilder();
@@ -956,7 +928,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 			$shares = $this->getShares($calendarId);
 			if ($calendarData) {
 				$this->dispatcher->dispatchTyped(new CalendarMovedToTrashEvent(
-					(int)$calendarId,
+					$calendarId,
 					$calendarData,
 					$shares
 				));
@@ -1292,24 +1264,17 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 		$this->addChange($calendarId, $objectUri, 1, $calendarType);
 
 		$objectRow = $this->getCalendarObject($calendarId, $objectUri, $calendarType);
+		assert($objectRow !== null);
+
 		if ($calendarType === self::CALENDAR_TYPE_CALENDAR) {
 			$calendarRow = $this->getCalendarById($calendarId);
 			$shares = $this->getShares($calendarId);
 
-			$this->dispatcher->dispatchTyped(new CalendarObjectCreatedEvent((int)$calendarId, $calendarRow, $shares, $objectRow));
+			$this->dispatcher->dispatchTyped(new CalendarObjectCreatedEvent($calendarId, $calendarRow, $shares, $objectRow));
 		} else {
 			$subscriptionRow = $this->getSubscriptionById($calendarId);
 
-			$this->dispatcher->dispatchTyped(new CachedCalendarObjectCreatedEvent((int)$calendarId, $subscriptionRow, [], $objectRow));
-			$this->legacyDispatcher->dispatch('\OCA\DAV\CalDAV\CalDavBackend::createCachedCalendarObject', new GenericEvent(
-				'\OCA\DAV\CalDAV\CalDavBackend::createCachedCalendarObject',
-				[
-					'subscriptionId' => $calendarId,
-					'calendarData' => $subscriptionRow,
-					'shares' => [],
-					'objectData' => $objectRow,
-				]
-			));
+			$this->dispatcher->dispatchTyped(new CachedCalendarObjectCreatedEvent($calendarId, $subscriptionRow, [], $objectRow));
 		}
 
 		return '"' . $extraData['etag'] . '"';
@@ -1361,20 +1326,11 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 				$calendarRow = $this->getCalendarById($calendarId);
 				$shares = $this->getShares($calendarId);
 
-				$this->dispatcher->dispatchTyped(new CalendarObjectUpdatedEvent((int)$calendarId, $calendarRow, $shares, $objectRow));
+				$this->dispatcher->dispatchTyped(new CalendarObjectUpdatedEvent($calendarId, $calendarRow, $shares, $objectRow));
 			} else {
 				$subscriptionRow = $this->getSubscriptionById($calendarId);
 
-				$this->dispatcher->dispatchTyped(new CachedCalendarObjectUpdatedEvent((int)$calendarId, $subscriptionRow, [], $objectRow));
-				$this->legacyDispatcher->dispatch('\OCA\DAV\CalDAV\CalDavBackend::updateCachedCalendarObject', new GenericEvent(
-					'\OCA\DAV\CalDAV\CalDavBackend::updateCachedCalendarObject',
-					[
-						'subscriptionId' => $calendarId,
-						'calendarData' => $subscriptionRow,
-						'shares' => [],
-						'objectData' => $objectRow,
-					]
-				));
+				$this->dispatcher->dispatchTyped(new CachedCalendarObjectUpdatedEvent($calendarId, $subscriptionRow, [], $objectRow));
 			}
 		}
 
@@ -1387,13 +1343,14 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	 * @param int $sourceCalendarId
 	 * @param int $targetCalendarId
 	 * @param int $objectId
-	 * @param string $principalUri
+	 * @param string $oldPrincipalUri
+	 * @param string $newPrincipalUri
 	 * @param int $calendarType
 	 * @return bool
 	 * @throws Exception
 	 */
-	public function moveCalendarObject(int $sourceCalendarId, int $targetCalendarId, int $objectId, string $principalUri, int $calendarType = self::CALENDAR_TYPE_CALENDAR): bool {
-		$object = $this->getCalendarObjectById($principalUri, $objectId);
+	public function moveCalendarObject(int $sourceCalendarId, int $targetCalendarId, int $objectId, string $oldPrincipalUri, string $newPrincipalUri, int $calendarType = self::CALENDAR_TYPE_CALENDAR): bool {
+		$object = $this->getCalendarObjectById($oldPrincipalUri, $objectId);
 		if (empty($object)) {
 			return false;
 		}
@@ -1411,21 +1368,23 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 		$this->addChange($sourceCalendarId, $object['uri'], 1, $calendarType);
 		$this->addChange($targetCalendarId, $object['uri'], 3, $calendarType);
 
-		$object = $this->getCalendarObjectById($principalUri, $objectId);
+		$object = $this->getCalendarObjectById($newPrincipalUri, $objectId);
 		// Calendar Object wasn't found - possibly because it was deleted in the meantime by a different client
 		if (empty($object)) {
 			return false;
 		}
 
-		$calendarRow = $this->getCalendarById($targetCalendarId);
+		$targetCalendarRow = $this->getCalendarById($targetCalendarId);
 		// the calendar this event is being moved to does not exist any longer
-		if (empty($calendarRow)) {
+		if (empty($targetCalendarRow)) {
 			return false;
 		}
 
 		if ($calendarType === self::CALENDAR_TYPE_CALENDAR) {
-			$shares = $this->getShares($targetCalendarId);
-			$this->dispatcher->dispatchTyped(new CalendarObjectUpdatedEvent($targetCalendarId, $calendarRow, $shares, $object));
+			$sourceShares = $this->getShares($sourceCalendarId);
+			$targetShares = $this->getShares($targetCalendarId);
+			$sourceCalendarRow = $this->getCalendarById($sourceCalendarId);
+			$this->dispatcher->dispatchTyped(new CalendarObjectMovedEvent($sourceCalendarId, $sourceCalendarRow, $targetCalendarId, $targetCalendarRow, $sourceShares, $targetShares, $object));
 		}
 		return true;
 	}
@@ -1477,20 +1436,11 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 				$calendarRow = $this->getCalendarById($calendarId);
 				$shares = $this->getShares($calendarId);
 
-				$this->dispatcher->dispatchTyped(new CalendarObjectDeletedEvent((int)$calendarId, $calendarRow, $shares, $data));
+				$this->dispatcher->dispatchTyped(new CalendarObjectDeletedEvent($calendarId, $calendarRow, $shares, $data));
 			} else {
 				$subscriptionRow = $this->getSubscriptionById($calendarId);
 
-				$this->dispatcher->dispatchTyped(new CachedCalendarObjectDeletedEvent((int)$calendarId, $subscriptionRow, [], $data));
-				$this->legacyDispatcher->dispatch('\OCA\DAV\CalDAV\CalDavBackend::deleteCachedCalendarObject', new GenericEvent(
-					'\OCA\DAV\CalDAV\CalDavBackend::deleteCachedCalendarObject',
-					[
-						'subscriptionId' => $calendarId,
-						'calendarData' => $subscriptionRow,
-						'shares' => [],
-						'objectData' => $data,
-					]
-				));
+				$this->dispatcher->dispatchTyped(new CachedCalendarObjectDeletedEvent($calendarId, $subscriptionRow, [], $data));
 			}
 		} else {
 			$pathInfo = pathinfo($data['uri']);
@@ -1530,7 +1480,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 			if ($calendarData !== null) {
 				$this->dispatcher->dispatchTyped(
 					new CalendarObjectMovedToTrashEvent(
-						(int)$calendarId,
+						$calendarId,
 						$calendarData,
 						$this->getShares($calendarId),
 						$data
@@ -1634,7 +1584,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	 * Note that especially time-range-filters may be difficult to parse. A
 	 * time-range filter specified on a VEVENT must for instance also handle
 	 * recurrence rules correctly.
-	 * A good example of how to interprete all these filters can also simply
+	 * A good example of how to interpret all these filters can also simply
 	 * be found in Sabre\CalDAV\CalendarQueryFilter. This class is as correct
 	 * as possible, so it gives you a good idea on what type of stuff you need
 	 * to think of.
@@ -2501,12 +2451,6 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 
 		$subscriptionRow = $this->getSubscriptionById($subscriptionId);
 		$this->dispatcher->dispatchTyped(new SubscriptionCreatedEvent($subscriptionId, $subscriptionRow));
-		$this->legacyDispatcher->dispatch('\OCA\DAV\CalDAV\CalDavBackend::createSubscription', new GenericEvent(
-			'\OCA\DAV\CalDAV\CalDavBackend::createSubscription',
-			[
-				'subscriptionId' => $subscriptionId,
-				'subscriptionData' => $subscriptionRow,
-			]));
 
 		return $subscriptionId;
 	}
@@ -2554,13 +2498,6 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 
 			$subscriptionRow = $this->getSubscriptionById($subscriptionId);
 			$this->dispatcher->dispatchTyped(new SubscriptionUpdatedEvent((int)$subscriptionId, $subscriptionRow, [], $mutations));
-			$this->legacyDispatcher->dispatch('\OCA\DAV\CalDAV\CalDavBackend::updateSubscription', new GenericEvent(
-				'\OCA\DAV\CalDAV\CalDavBackend::updateSubscription',
-				[
-					'subscriptionId' => $subscriptionId,
-					'subscriptionData' => $subscriptionRow,
-					'propertyMutations' => $mutations,
-				]));
 
 			return true;
 		});
@@ -2575,13 +2512,6 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	public function deleteSubscription($subscriptionId) {
 		$subscriptionRow = $this->getSubscriptionById($subscriptionId);
 
-		$this->legacyDispatcher->dispatch('\OCA\DAV\CalDAV\CalDavBackend::deleteSubscription', new GenericEvent(
-			'\OCA\DAV\CalDAV\CalDavBackend::deleteSubscription',
-			[
-				'subscriptionId' => $subscriptionId,
-				'subscriptionData' => $this->getSubscriptionById($subscriptionId),
-			]));
-
 		$query = $this->db->getQueryBuilder();
 		$query->delete('calendarsubscriptions')
 			->where($query->expr()->eq('id', $query->createNamedParameter($subscriptionId)))
@@ -2870,34 +2800,26 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	}
 
 	/**
-	 * @param IShareable $shareable
-	 * @param array $add
-	 * @param array $remove
+	 * @param list<array{href: string, commonName: string, readOnly: bool}> $add
+	 * @param list<string> $remove
 	 */
-	public function updateShares($shareable, $add, $remove) {
+	public function updateShares(IShareable $shareable, array $add, array $remove): void {
 		$calendarId = $shareable->getResourceId();
 		$calendarRow = $this->getCalendarById($calendarId);
+		if ($calendarRow === null) {
+			throw new \RuntimeException('Trying to update shares for innexistant calendar: ' . $calendarId);
+		}
 		$oldShares = $this->getShares($calendarId);
 
-		$this->legacyDispatcher->dispatch('\OCA\DAV\CalDAV\CalDavBackend::updateShares', new GenericEvent(
-			'\OCA\DAV\CalDAV\CalDavBackend::updateShares',
-			[
-				'calendarId' => $calendarId,
-				'calendarData' => $calendarRow,
-				'shares' => $oldShares,
-				'add' => $add,
-				'remove' => $remove,
-			]));
 		$this->calendarSharingBackend->updateShares($shareable, $add, $remove);
 
-		$this->dispatcher->dispatchTyped(new CalendarShareUpdatedEvent((int)$calendarId, $calendarRow, $oldShares, $add, $remove));
+		$this->dispatcher->dispatchTyped(new CalendarShareUpdatedEvent($calendarId, $calendarRow, $oldShares, $add, $remove));
 	}
 
 	/**
-	 * @param int $resourceId
-	 * @return array
+	 * @return list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}>
 	 */
-	public function getShares($resourceId) {
+	public function getShares(int $resourceId): array {
 		return $this->calendarSharingBackend->getShares($resourceId);
 	}
 
@@ -2909,13 +2831,6 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	public function setPublishStatus($value, $calendar) {
 		$calendarId = $calendar->getResourceId();
 		$calendarData = $this->getCalendarById($calendarId);
-		$this->legacyDispatcher->dispatch('\OCA\DAV\CalDAV\CalDavBackend::publishCalendar', new GenericEvent(
-			'\OCA\DAV\CalDAV\CalDavBackend::updateShares',
-			[
-				'calendarId' => $calendarId,
-				'calendarData' => $calendarData,
-				'public' => $value,
-			]));
 
 		$query = $this->db->getQueryBuilder();
 		if ($value) {
@@ -2930,7 +2845,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 				]);
 			$query->executeStatement();
 
-			$this->dispatcher->dispatchTyped(new CalendarPublishedEvent((int)$calendarId, $calendarData, $publicUri));
+			$this->dispatcher->dispatchTyped(new CalendarPublishedEvent($calendarId, $calendarData, $publicUri));
 			return $publicUri;
 		}
 		$query->delete('dav_shares')
@@ -2938,7 +2853,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 			->andWhere($query->expr()->eq('access', $query->createNamedParameter(self::ACCESS_PUBLIC)));
 		$query->executeStatement();
 
-		$this->dispatcher->dispatchTyped(new CalendarUnpublishedEvent((int)$calendarId, $calendarData));
+		$this->dispatcher->dispatchTyped(new CalendarUnpublishedEvent($calendarId, $calendarData));
 		return null;
 	}
 
@@ -2961,15 +2876,13 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 
 	/**
 	 * @param int $resourceId
-	 * @param array $acl
-	 * @return array
+	 * @param list<array{privilege: string, principal: string, protected: bool}> $acl
+	 * @return list<array{privilege: string, principal: string, protected: bool}>
 	 */
-	public function applyShareAcl($resourceId, $acl) {
+	public function applyShareAcl(int $resourceId, array $acl): array {
 		return $this->calendarSharingBackend->applyShareAcl($resourceId, $acl);
 	}
 
-
-
 	/**
 	 * update properties table
 	 *
diff --git a/apps/dav/lib/CalDAV/Calendar.php b/apps/dav/lib/CalDAV/Calendar.php
index 75c815c3b0a..92ad3242d78 100644
--- a/apps/dav/lib/CalDAV/Calendar.php
+++ b/apps/dav/lib/CalDAV/Calendar.php
@@ -51,27 +51,11 @@ use Sabre\DAV\PropPatch;
  * @property CalDavBackend $caldavBackend
  */
 class Calendar extends \Sabre\CalDAV\Calendar implements IRestorable, IShareable, IMoveTarget {
+	private IConfig $config;
+	protected IL10N $l10n;
+	private bool $useTrashbin = true;
+	private LoggerInterface $logger;
 
-	/** @var IConfig */
-	private $config;
-
-	/** @var IL10N */
-	protected $l10n;
-
-	/** @var bool */
-	private $useTrashbin = true;
-
-	/** @var LoggerInterface */
-	private $logger;
-
-	/**
-	 * Calendar constructor.
-	 *
-	 * @param BackendInterface $caldavBackend
-	 * @param $calendarInfo
-	 * @param IL10N $l10n
-	 * @param IConfig $config
-	 */
 	public function __construct(BackendInterface $caldavBackend, $calendarInfo, IL10N $l10n, IConfig $config, LoggerInterface $logger) {
 		// Convert deletion date to ISO8601 string
 		if (isset($calendarInfo[TrashbinPlugin::PROPERTY_DELETED_AT])) {
@@ -96,25 +80,10 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IRestorable, IShareable
 	}
 
 	/**
-	 * Updates the list of shares.
-	 *
-	 * The first array is a list of people that are to be added to the
-	 * resource.
-	 *
-	 * Every element in the add array has the following properties:
-	 *   * href - A url. Usually a mailto: address
-	 *   * commonName - Usually a first and last name, or false
-	 *   * summary - A description of the share, can also be false
-	 *   * readOnly - A boolean value
-	 *
-	 * Every element in the remove array is just the address string.
-	 *
-	 * @param array $add
-	 * @param array $remove
-	 * @return void
+	 * {@inheritdoc}
 	 * @throws Forbidden
 	 */
-	public function updateShares(array $add, array $remove) {
+	public function updateShares(array $add, array $remove): void {
 		if ($this->isShared()) {
 			throw new Forbidden();
 		}
@@ -131,19 +100,16 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IRestorable, IShareable
 	 *   * readOnly - boolean
 	 *   * summary - Optional, a description for the share
 	 *
-	 * @return array
+	 * @return list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}>
 	 */
-	public function getShares() {
+	public function getShares(): array {
 		if ($this->isShared()) {
 			return [];
 		}
 		return $this->caldavBackend->getShares($this->getResourceId());
 	}
 
-	/**
-	 * @return int
-	 */
-	public function getResourceId() {
+	public function getResourceId(): int {
 		return $this->calendarInfo['id'];
 	}
 
@@ -155,7 +121,9 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IRestorable, IShareable
 	}
 
 	/**
-	 * @return array
+	 * @param int $resourceId
+	 * @param list<array{privilege: string, principal: string, protected: bool}> $acl
+	 * @return list<array{privilege: string, principal: ?string, protected: bool}>
 	 */
 	public function getACL() {
 		$acl = [
@@ -246,16 +214,18 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IRestorable, IShareable
 			parent::getOwner(),
 			'principals/system/public'
 		];
-		return array_filter($acl, function ($rule) use ($allowedPrincipals) {
+		/** @var list<array{privilege: string, principal: string, protected: bool}> $acl */
+		$acl = array_filter($acl, function (array $rule) use ($allowedPrincipals): bool {
 			return \in_array($rule['principal'], $allowedPrincipals, true);
 		});
+		return $acl;
 	}
 
 	public function getChildACL() {
 		return $this->getACL();
 	}
 
-	public function getOwner() {
+	public function getOwner(): ?string {
 		if (isset($this->calendarInfo['{http://owncloud.org/ns}owner-principal'])) {
 			return $this->calendarInfo['{http://owncloud.org/ns}owner-principal'];
 		}
@@ -400,7 +370,7 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IRestorable, IShareable
 		return isset($this->calendarInfo['{http://owncloud.org/ns}public']);
 	}
 
-	protected function isShared() {
+	public function isShared() {
 		if (!isset($this->calendarInfo['{http://owncloud.org/ns}owner-principal'])) {
 			return false;
 		}
@@ -412,6 +382,13 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IRestorable, IShareable
 		return isset($this->calendarInfo['{http://calendarserver.org/ns/}source']);
 	}
 
+	public function isDeleted(): bool {
+		if (!isset($this->calendarInfo[TrashbinPlugin::PROPERTY_DELETED_AT])) {
+			return false;
+		}
+		return $this->calendarInfo[TrashbinPlugin::PROPERTY_DELETED_AT] !== null;
+	}
+
 	/**
 	 * @inheritDoc
 	 */
@@ -443,7 +420,7 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IRestorable, IShareable
 		}
 
 		try {
-			return $this->caldavBackend->moveCalendarObject($sourceNode->getCalendarId(), (int)$this->calendarInfo['id'], $sourceNode->getId(), $sourceNode->getPrincipalUri());
+			return $this->caldavBackend->moveCalendarObject($sourceNode->getCalendarId(), (int)$this->calendarInfo['id'], $sourceNode->getId(), $sourceNode->getOwner(), $this->getOwner());
 		} catch (Exception $e) {
 			$this->logger->error('Could not move calendar object: ' . $e->getMessage(), ['exception' => $e]);
 			return false;
diff --git a/apps/dav/lib/CalDAV/CalendarImpl.php b/apps/dav/lib/CalDAV/CalendarImpl.php
index 406389e3a3d..27a428a4075 100644
--- a/apps/dav/lib/CalDAV/CalendarImpl.php
+++ b/apps/dav/lib/CalDAV/CalendarImpl.php
@@ -138,7 +138,7 @@ class CalendarImpl implements ICreateFromString {
 	 * Create a new calendar event for this calendar
 	 * by way of an ICS string
 	 *
-	 * @param string $name the file name - needs to contan the .ics ending
+	 * @param string $name the file name - needs to contain the .ics ending
 	 * @param string $calendarData a string containing a valid VEVENT ics
 	 *
 	 * @throws CalendarException
diff --git a/apps/dav/lib/CalDAV/CalendarObject.php b/apps/dav/lib/CalDAV/CalendarObject.php
index c927254fba3..32bcff900c2 100644
--- a/apps/dav/lib/CalDAV/CalendarObject.php
+++ b/apps/dav/lib/CalDAV/CalendarObject.php
@@ -162,4 +162,11 @@ class CalendarObject extends \Sabre\CalDAV\CalendarObject {
 	public function getPrincipalUri(): string {
 		return $this->calendarInfo['principaluri'];
 	}
+
+	public function getOwner(): ?string {
+		if (isset($this->calendarInfo['{http://owncloud.org/ns}owner-principal'])) {
+			return $this->calendarInfo['{http://owncloud.org/ns}owner-principal'];
+		}
+		return parent::getOwner();
+	}
 }
diff --git a/apps/dav/lib/CalDAV/PublicCalendar.php b/apps/dav/lib/CalDAV/PublicCalendar.php
index 4a29c8d237a..16c7f86917d 100644
--- a/apps/dav/lib/CalDAV/PublicCalendar.php
+++ b/apps/dav/lib/CalDAV/PublicCalendar.php
@@ -84,7 +84,7 @@ class PublicCalendar extends Calendar {
 	 * public calendars are always shared
 	 * @return bool
 	 */
-	protected function isShared() {
+	public function isShared() {
 		return true;
 	}
 }
diff --git a/apps/dav/lib/CalDAV/Publishing/Xml/Publisher.php b/apps/dav/lib/CalDAV/Publishing/Xml/Publisher.php
index 35bce872bf8..cbff5e66a85 100644
--- a/apps/dav/lib/CalDAV/Publishing/Xml/Publisher.php
+++ b/apps/dav/lib/CalDAV/Publishing/Xml/Publisher.php
@@ -55,7 +55,7 @@ class Publisher implements XmlSerializable {
 	}
 
 	/**
-	 * The xmlSerialize metod is called during xml writing.
+	 * The xmlSerialize method is called during xml writing.
 	 *
 	 * Use the $writer argument to write its own xml serialization.
 	 *
diff --git a/apps/dav/lib/CalDAV/Schedule/Plugin.php b/apps/dav/lib/CalDAV/Schedule/Plugin.php
index 96bacce4454..44517541faa 100644
--- a/apps/dav/lib/CalDAV/Schedule/Plugin.php
+++ b/apps/dav/lib/CalDAV/Schedule/Plugin.php
@@ -30,6 +30,7 @@ namespace OCA\DAV\CalDAV\Schedule;
 
 use DateTimeZone;
 use OCA\DAV\CalDAV\CalDavBackend;
+use OCA\DAV\CalDAV\Calendar;
 use OCA\DAV\CalDAV\CalendarHome;
 use OCP\IConfig;
 use Sabre\CalDAV\ICalendar;
@@ -178,7 +179,7 @@ class Plugin extends \Sabre\CalDAV\Schedule\Plugin {
 
 		// If parent::scheduleLocalDelivery set scheduleStatus to 1.2,
 		// it means that it was successfully delivered locally.
-		// Meaning that the ACL plugin is loaded and that a principial
+		// Meaning that the ACL plugin is loaded and that a principal
 		// exists for the given recipient id, no need to double check
 		/** @var \Sabre\DAVACL\Plugin $aclPlugin */
 		$aclPlugin = $this->server->getPlugin('acl');
@@ -299,12 +300,14 @@ EOF;
 					return null;
 				}
 
+				$isResourceOrRoom = strpos($principalUrl, 'principals/calendar-resources') === 0 ||
+					strpos($principalUrl, 'principals/calendar-rooms') === 0;
+
 				if (strpos($principalUrl, 'principals/users') === 0) {
 					[, $userId] = split($principalUrl);
 					$uri = $this->config->getUserValue($userId, 'dav', 'defaultCalendar', CalDavBackend::PERSONAL_CALENDAR_URI);
 					$displayName = CalDavBackend::PERSONAL_CALENDAR_NAME;
-				} elseif (strpos($principalUrl, 'principals/calendar-resources') === 0 ||
-						  strpos($principalUrl, 'principals/calendar-rooms') === 0) {
+				} elseif ($isResourceOrRoom) {
 					$uri = CalDavBackend::RESOURCE_BOOKING_CALENDAR_URI;
 					$displayName = CalDavBackend::RESOURCE_BOOKING_CALENDAR_NAME;
 				} else {
@@ -316,9 +319,40 @@ EOF;
 				/** @var CalendarHome $calendarHome */
 				$calendarHome = $this->server->tree->getNodeForPath($calendarHomePath);
 				if (!$calendarHome->childExists($uri)) {
-					$calendarHome->getCalDAVBackend()->createCalendar($principalUrl, $uri, [
-						'{DAV:}displayname' => $displayName,
-					]);
+					// If the default calendar doesn't exist
+					if ($isResourceOrRoom) {
+						$calendarHome->getCalDAVBackend()->createCalendar($principalUrl, $uri, [
+							'{DAV:}displayname' => $displayName,
+						]);
+					} else {
+						// And we're not handling scheduling on resource/room booking
+						$userCalendars = [];
+						/**
+						 * If the default calendar of the user isn't set and the
+						 * fallback doesn't match any of the user's calendar
+						 * try to find the first "personal" calendar we can write to
+						 * instead of creating a new one.
+						 * A appropriate personal calendar to receive invites:
+						 * - isn't a calendar subscription
+						 * - user can write to it (no virtual/3rd-party calendars)
+						 * - calendar isn't a share
+						 */
+						foreach ($calendarHome->getChildren() as $node) {
+							if ($node instanceof Calendar && !$node->isSubscription() && $node->canWrite() && !$node->isShared() && !$node->isDeleted()) {
+								$userCalendars[] = $node;
+							}
+						}
+
+						if (count($userCalendars) > 0) {
+							// Calendar backend returns calendar by calendarorder property
+							$uri = $userCalendars[0]->getName();
+						} else {
+							// Otherwise if we have really nothing, create a new calendar
+							$calendarHome->getCalDAVBackend()->createCalendar($principalUrl, $uri, [
+								'{DAV:}displayname' => $displayName,
+							]);
+						}
+					}
 				}
 
 				$result = $this->server->getPropertiesForPath($calendarHomePath . '/' . $uri, [], 1);
@@ -533,7 +567,7 @@ EOF;
 		}
 
 		// If more than one Free-Busy property was returned, it means that an event
-		// starts or ends inside this time-range, so it's not availabe and we return false
+		// starts or ends inside this time-range, so it's not available and we return false
 		if (count($freeBusyProperties) > 1) {
 			return false;
 		}
diff --git a/apps/dav/lib/CalDAV/WebcalCaching/RefreshWebcalService.php b/apps/dav/lib/CalDAV/WebcalCaching/RefreshWebcalService.php
index 0dbe7398f52..eadeea3457c 100644
--- a/apps/dav/lib/CalDAV/WebcalCaching/RefreshWebcalService.php
+++ b/apps/dav/lib/CalDAV/WebcalCaching/RefreshWebcalService.php
@@ -56,14 +56,15 @@ use function count;
 class RefreshWebcalService {
 
 	/** @var CalDavBackend */
-	private $calDavBackend;
+	private CalDavBackend $calDavBackend;
 
 	/** @var IClientService */
-	private $clientService;
+	private IClientService $clientService;
 
 	/** @var IConfig */
-	private $config;
+	private IConfig $config;
 
+	/** @var LoggerInterface */
 	private LoggerInterface $logger;
 
 	public const REFRESH_RATE = '{http://apple.com/ns/ical/}refreshrate';
@@ -71,13 +72,7 @@ class RefreshWebcalService {
 	public const STRIP_ATTACHMENTS = '{http://calendarserver.org/ns/}subscribed-strip-attachments';
 	public const STRIP_TODOS = '{http://calendarserver.org/ns/}subscribed-strip-todos';
 
-	/**
-	 * RefreshWebcalJob constructor.
-	 */
-	public function __construct(CalDavBackend $calDavBackend,
-								IClientService $clientService,
-								IConfig $config,
-								LoggerInterface $logger) {
+	public function __construct(CalDavBackend $calDavBackend, IClientService $clientService, IConfig $config, LoggerInterface $logger) {
 		$this->calDavBackend = $calDavBackend;
 		$this->clientService = $clientService;
 		$this->config = $config;
@@ -131,12 +126,12 @@ class RefreshWebcalService {
 					continue;
 				}
 
-				$uri = $this->getRandomCalendarObjectUri();
+				$objectUri = $this->getRandomCalendarObjectUri();
 				$calendarData = $vObject->serialize();
 				try {
-					$this->calDavBackend->createCalendarObject($subscription['id'], $uri, $calendarData, CalDavBackend::CALENDAR_TYPE_SUBSCRIPTION);
+					$this->calDavBackend->createCalendarObject($subscription['id'], $objectUri, $calendarData, CalDavBackend::CALENDAR_TYPE_SUBSCRIPTION);
 				} catch (NoInstancesException | BadRequest $ex) {
-					$this->logger->error($ex->getMessage(), ['exception' => $ex]);
+					$this->logger->error('Unable to create calendar object from subscription {subscriptionId}', ['exception' => $ex, 'subscriptionId' => $subscription['id'], 'source' => $subscription['source']]);
 				}
 			}
 
@@ -147,20 +142,14 @@ class RefreshWebcalService {
 
 			$this->updateSubscription($subscription, $mutations);
 		} catch (ParseException $ex) {
-			$subscriptionId = $subscription['id'];
-
-			$this->logger->error("Subscription $subscriptionId could not be refreshed due to a parsing error", ['exception' => $ex]);
+			$this->logger->error("Subscription {subscriptionId} could not be refreshed due to a parsing error", ['exception' => $ex, 'subscriptionId' => $subscription['id']]);
 		}
 	}
 
 	/**
 	 * loads subscription from backend
-	 *
-	 * @param string $principalUri
-	 * @param string $uri
-	 * @return array|null
 	 */
-	public function getSubscription(string $principalUri, string $uri) {
+	public function getSubscription(string $principalUri, string $uri): ?array {
 		$subscriptions = array_values(array_filter(
 			$this->calDavBackend->getSubscriptionsForUser($principalUri),
 			function ($sub) use ($uri) {
@@ -177,12 +166,8 @@ class RefreshWebcalService {
 
 	/**
 	 * gets webcal feed from remote server
-	 *
-	 * @param array $subscription
-	 * @param array &$mutations
-	 * @return null|string
 	 */
-	private function queryWebcalFeed(array $subscription, array &$mutations) {
+	private function queryWebcalFeed(array $subscription, array &$mutations): ?string {
 		$client = $this->clientService->newClient();
 
 		$didBreak301Chain = false;
@@ -244,7 +229,7 @@ class RefreshWebcalService {
 						$jCalendar = Reader::readJson($body, Reader::OPTION_FORGIVING);
 					} catch (Exception $ex) {
 						// In case of a parsing error return null
-						$this->logger->debug("Subscription $subscriptionId could not be parsed");
+						$this->logger->warning("Subscription $subscriptionId could not be parsed", ['exception' => $ex]);
 						return null;
 					}
 					return $jCalendar->serialize();
@@ -254,7 +239,7 @@ class RefreshWebcalService {
 						$xCalendar = Reader::readXML($body);
 					} catch (Exception $ex) {
 						// In case of a parsing error return null
-						$this->logger->debug("Subscription $subscriptionId could not be parsed");
+						$this->logger->warning("Subscription $subscriptionId could not be parsed", ['exception' => $ex]);
 						return null;
 					}
 					return $xCalendar->serialize();
@@ -265,7 +250,7 @@ class RefreshWebcalService {
 						$vCalendar = Reader::read($body);
 					} catch (Exception $ex) {
 						// In case of a parsing error return null
-						$this->logger->debug("Subscription $subscriptionId could not be parsed");
+						$this->logger->warning("Subscription $subscriptionId could not be parsed", ['exception' => $ex]);
 						return null;
 					}
 					return $vCalendar->serialize();
@@ -291,11 +276,8 @@ class RefreshWebcalService {
 	 *  - the webcal feed suggests a refreshrate
 	 *  - return suggested refreshrate if user didn't set a custom one
 	 *
-	 * @param array $subscription
-	 * @param string $webcalData
-	 * @return string|null
 	 */
-	private function checkWebcalDataForRefreshRate($subscription, $webcalData) {
+	private function checkWebcalDataForRefreshRate(array $subscription, string $webcalData): ?string {
 		// if there is no refreshrate stored in the database, check the webcal feed
 		// whether it suggests any refresh rate and store that in the database
 		if (isset($subscription[self::REFRESH_RATE]) && $subscription[self::REFRESH_RATE] !== null) {
@@ -353,7 +335,7 @@ class RefreshWebcalService {
 	 * @param string $url
 	 * @return string|null
 	 */
-	private function cleanURL(string $url) {
+	private function cleanURL(string $url): ?string {
 		$parsed = parse_url($url);
 		if ($parsed === false) {
 			return null;
diff --git a/apps/dav/lib/CardDAV/Activity/Backend.php b/apps/dav/lib/CardDAV/Activity/Backend.php
index b713284e182..8c8c643e287 100644
--- a/apps/dav/lib/CardDAV/Activity/Backend.php
+++ b/apps/dav/lib/CardDAV/Activity/Backend.php
@@ -32,6 +32,7 @@ use OCP\App\IAppManager;
 use OCP\IGroup;
 use OCP\IGroupManager;
 use OCP\IUser;
+use OCP\IUserManager;
 use OCP\IUserSession;
 use Sabre\CardDAV\Plugin;
 use Sabre\VObject\Reader;
@@ -50,14 +51,19 @@ class Backend {
 	/** @var IAppManager */
 	protected $appManager;
 
+	/** @var IUserManager */
+	protected $userManager;
+
 	public function __construct(IActivityManager $activityManager,
 								IGroupManager $groupManager,
 								IUserSession $userSession,
-								IAppManager $appManager) {
+								IAppManager $appManager,
+								IUserManager $userManager) {
 		$this->activityManager = $activityManager;
 		$this->groupManager = $groupManager;
 		$this->userSession = $userSession;
 		$this->appManager = $appManager;
+		$this->userManager = $userManager;
 	}
 
 	/**
@@ -103,7 +109,14 @@ class Backend {
 			return;
 		}
 
-		$principal = explode('/', $addressbookData['principaluri']);
+		$principalUri = $addressbookData['principaluri'];
+
+		// We are not interested in changes from the system addressbook
+		if ($principalUri === 'principals/system/system') {
+			return;
+		}
+
+		$principal = explode('/', $principalUri);
 		$owner = array_pop($principal);
 
 		$currentUser = $this->userSession->getUser();
@@ -132,6 +145,11 @@ class Backend {
 		}
 
 		foreach ($users as $user) {
+			if ($action === Addressbook::SUBJECT_DELETE && !$this->userManager->userExists($user)) {
+				// Avoid creating addressbook_delete activities for deleted users
+				continue;
+			}
+
 			$event->setAffectedUser($user)
 				->setSubject(
 					$user === $currentUser ? $action . '_self' : $action,
@@ -393,7 +411,14 @@ class Backend {
 			return;
 		}
 
-		$principal = explode('/', $addressbookData['principaluri']);
+		$principalUri = $addressbookData['principaluri'];
+
+		// We are not interested in changes from the system addressbook
+		if ($principalUri === 'principals/system/system') {
+			return;
+		}
+
+		$principal = explode('/', $principalUri);
 		$owner = array_pop($principal);
 
 		$currentUser = $this->userSession->getUser();
diff --git a/apps/dav/lib/CardDAV/AddressBook.php b/apps/dav/lib/CardDAV/AddressBook.php
index 9bd24bedbac..bca478feec1 100644
--- a/apps/dav/lib/CardDAV/AddressBook.php
+++ b/apps/dav/lib/CardDAV/AddressBook.php
@@ -67,17 +67,15 @@ class AddressBook extends \Sabre\CardDAV\AddressBook implements IShareable {
 	 * Every element in the add array has the following properties:
 	 *   * href - A url. Usually a mailto: address
 	 *   * commonName - Usually a first and last name, or false
-	 *   * summary - A description of the share, can also be false
 	 *   * readOnly - A boolean value
 	 *
 	 * Every element in the remove array is just the address string.
 	 *
-	 * @param array $add
-	 * @param array $remove
-	 * @return void
+	 * @param list<array{href: string, commonName: string, readOnly: bool}> $add
+	 * @param list<string> $remove
 	 * @throws Forbidden
 	 */
-	public function updateShares(array $add, array $remove) {
+	public function updateShares(array $add, array $remove): void {
 		if ($this->isShared()) {
 			throw new Forbidden();
 		}
@@ -92,11 +90,10 @@ class AddressBook extends \Sabre\CardDAV\AddressBook implements IShareable {
 	 *   * commonName - Optional, for example a first + last name
 	 *   * status - See the Sabre\CalDAV\SharingPlugin::STATUS_ constants.
 	 *   * readOnly - boolean
-	 *   * summary - Optional, a description for the share
 	 *
-	 * @return array
+	 * @return list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}>
 	 */
-	public function getShares() {
+	public function getShares(): array {
 		if ($this->isShared()) {
 			return [];
 		}
@@ -163,14 +160,11 @@ class AddressBook extends \Sabre\CardDAV\AddressBook implements IShareable {
 		return new Card($this->carddavBackend, $this->addressBookInfo, $obj);
 	}
 
-	/**
-	 * @return int
-	 */
-	public function getResourceId() {
+	public function getResourceId(): int {
 		return $this->addressBookInfo['id'];
 	}
 
-	public function getOwner() {
+	public function getOwner(): ?string {
 		if (isset($this->addressBookInfo['{http://owncloud.org/ns}owner-principal'])) {
 			return $this->addressBookInfo['{http://owncloud.org/ns}owner-principal'];
 		}
@@ -207,7 +201,7 @@ class AddressBook extends \Sabre\CardDAV\AddressBook implements IShareable {
 		return $this->carddavBackend->collectCardProperties($this->getResourceId(), 'CATEGORIES');
 	}
 
-	private function isShared() {
+	private function isShared(): bool {
 		if (!isset($this->addressBookInfo['{http://owncloud.org/ns}owner-principal'])) {
 			return false;
 		}
@@ -215,7 +209,7 @@ class AddressBook extends \Sabre\CardDAV\AddressBook implements IShareable {
 		return $this->addressBookInfo['{http://owncloud.org/ns}owner-principal'] !== $this->addressBookInfo['principaluri'];
 	}
 
-	private function canWrite() {
+	private function canWrite(): bool {
 		if (isset($this->addressBookInfo['{http://owncloud.org/ns}read-only'])) {
 			return !$this->addressBookInfo['{http://owncloud.org/ns}read-only'];
 		}
diff --git a/apps/dav/lib/CardDAV/AddressBookImpl.php b/apps/dav/lib/CardDAV/AddressBookImpl.php
index 3db20cb4220..2f7f0a22900 100644
--- a/apps/dav/lib/CardDAV/AddressBookImpl.php
+++ b/apps/dav/lib/CardDAV/AddressBookImpl.php
@@ -12,6 +12,7 @@
  * @author Joas Schilling <coding@schilljs.com>
  * @author John Molakvoæ <skjnldsv@protonmail.com>
  * @author Julius Härtl <jus@bitgrid.net>
+ * @author Thomas Citharel <nextcloud@tcit.fr>
  * @author Thomas Müller <thomas.mueller@tmit.eu>
  *
  * @license AGPL-3.0
@@ -206,7 +207,7 @@ class AddressBookImpl implements IAddressBook {
 	}
 
 	/**
-	 * @param object $id the unique identifier to a contact
+	 * @param int $id the unique identifier to a contact
 	 * @return bool successful or not
 	 * @since 5.0.0
 	 */
diff --git a/apps/dav/lib/CardDAV/CardDavBackend.php b/apps/dav/lib/CardDAV/CardDavBackend.php
index 864f3da9367..a9ca2eb30a3 100644
--- a/apps/dav/lib/CardDAV/CardDavBackend.php
+++ b/apps/dav/lib/CardDAV/CardDavBackend.php
@@ -58,30 +58,19 @@ use Sabre\CardDAV\Plugin;
 use Sabre\DAV\Exception\BadRequest;
 use Sabre\VObject\Component\VCard;
 use Sabre\VObject\Reader;
-use Symfony\Component\EventDispatcher\EventDispatcherInterface;
-use Symfony\Component\EventDispatcher\GenericEvent;
 
 class CardDavBackend implements BackendInterface, SyncSupport {
 	public const PERSONAL_ADDRESSBOOK_URI = 'contacts';
 	public const PERSONAL_ADDRESSBOOK_NAME = 'Contacts';
 
-	/** @var Principal */
-	private $principalBackend;
-
-	/** @var string */
-	private $dbCardsTable = 'cards';
-
-	/** @var string */
-	private $dbCardsPropertiesTable = 'cards_properties';
-
-	/** @var IDBConnection */
-	private $db;
-
-	/** @var Backend */
-	private $sharingBackend;
+	private Principal $principalBackend;
+	private string $dbCardsTable = 'cards';
+	private string $dbCardsPropertiesTable = 'cards_properties';
+	private IDBConnection $db;
+	private Backend $sharingBackend;
 
 	/** @var array properties to index */
-	public static $indexProperties = [
+	public static array $indexProperties = [
 		'BDAY', 'UID', 'N', 'FN', 'TITLE', 'ROLE', 'NOTE', 'NICKNAME',
 		'ORG', 'CATEGORIES', 'EMAIL', 'TEL', 'IMPP', 'ADR', 'URL', 'GEO',
 		'CLOUD', 'X-SOCIALPROFILE'];
@@ -89,18 +78,10 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	/**
 	 * @var string[] Map of uid => display name
 	 */
-	protected $userDisplayNames;
-
-	/** @var IUserManager */
-	private $userManager;
-
-	/** @var IEventDispatcher */
-	private $dispatcher;
-
-	/** @var EventDispatcherInterface */
-	private $legacyDispatcher;
-
-	private $etagCache = [];
+	protected array $userDisplayNames;
+	private IUserManager $userManager;
+	private IEventDispatcher $dispatcher;
+	private array $etagCache = [];
 
 	/**
 	 * CardDavBackend constructor.
@@ -110,19 +91,16 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	 * @param IUserManager $userManager
 	 * @param IGroupManager $groupManager
 	 * @param IEventDispatcher $dispatcher
-	 * @param EventDispatcherInterface $legacyDispatcher
 	 */
 	public function __construct(IDBConnection $db,
 								Principal $principalBackend,
 								IUserManager $userManager,
 								IGroupManager $groupManager,
-								IEventDispatcher $dispatcher,
-								EventDispatcherInterface $legacyDispatcher) {
+								IEventDispatcher $dispatcher) {
 		$this->db = $db;
 		$this->principalBackend = $principalBackend;
 		$this->userManager = $userManager;
 		$this->dispatcher = $dispatcher;
-		$this->legacyDispatcher = $legacyDispatcher;
 		$this->sharingBackend = new Backend($this->db, $this->userManager, $groupManager, $principalBackend, 'addressbook');
 	}
 
@@ -318,18 +296,14 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 		return $addressBook;
 	}
 
-	/**
-	 * @param $addressBookUri
-	 * @return array|null
-	 */
-	public function getAddressBooksByUri($principal, $addressBookUri) {
+	public function getAddressBooksByUri(string $principal, string $addressBookUri): ?array {
 		$query = $this->db->getQueryBuilder();
 		$result = $query->select(['id', 'uri', 'displayname', 'principaluri', 'description', 'synctoken'])
 			->from('addressbooks')
 			->where($query->expr()->eq('uri', $query->createNamedParameter($addressBookUri)))
 			->andWhere($query->expr()->eq('principaluri', $query->createNamedParameter($principal)))
 			->setMaxResults(1)
-			->execute();
+			->executeQuery();
 
 		$row = $result->fetch();
 		$result->closeCursor();
@@ -393,12 +367,12 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 				$query->set($key, $query->createNamedParameter($value));
 			}
 			$query->where($query->expr()->eq('id', $query->createNamedParameter($addressBookId)))
-				->execute();
+				->executeStatement();
 
 			$this->addChange($addressBookId, "", 2);
 
 			$addressBookRow = $this->getAddressBookById((int)$addressBookId);
-			$shares = $this->getShares($addressBookId);
+			$shares = $this->getShares((int)$addressBookId);
 			$this->dispatcher->dispatchTyped(new AddressBookUpdatedEvent((int)$addressBookId, $addressBookRow, $shares, $mutations));
 
 			return true;
@@ -468,30 +442,31 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	 * @return void
 	 */
 	public function deleteAddressBook($addressBookId) {
+		$addressBookId = (int)$addressBookId;
 		$addressBookData = $this->getAddressBookById($addressBookId);
 		$shares = $this->getShares($addressBookId);
 
 		$query = $this->db->getQueryBuilder();
 		$query->delete($this->dbCardsTable)
 			->where($query->expr()->eq('addressbookid', $query->createParameter('addressbookid')))
-			->setParameter('addressbookid', $addressBookId)
-			->execute();
+			->setParameter('addressbookid', $addressBookId, IQueryBuilder::PARAM_INT)
+			->executeStatement();
 
 		$query->delete('addressbookchanges')
 			->where($query->expr()->eq('addressbookid', $query->createParameter('addressbookid')))
-			->setParameter('addressbookid', $addressBookId)
-			->execute();
+			->setParameter('addressbookid', $addressBookId, IQueryBuilder::PARAM_INT)
+			->executeStatement();
 
 		$query->delete('addressbooks')
 			->where($query->expr()->eq('id', $query->createParameter('id')))
-			->setParameter('id', $addressBookId)
-			->execute();
+			->setParameter('id', $addressBookId, IQueryBuilder::PARAM_INT)
+			->executeStatement();
 
 		$this->sharingBackend->deleteAllShares($addressBookId);
 
 		$query->delete($this->dbCardsPropertiesTable)
-			->where($query->expr()->eq('addressbookid', $query->createNamedParameter($addressBookId)))
-			->execute();
+			->where($query->expr()->eq('addressbookid', $query->createNamedParameter($addressBookId, IQueryBuilder::PARAM_INT)))
+			->executeStatement();
 
 		if ($addressBookData) {
 			$this->dispatcher->dispatchTyped(new AddressBookDeletedEvent($addressBookId, $addressBookData, $shares));
@@ -511,7 +486,7 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	 *   * size - The size of the card in bytes.
 	 *
 	 * If these last two properties are provided, less time will be spent
-	 * calculating them. If they are specified, you can also ommit carddata.
+	 * calculating them. If they are specified, you can also omit carddata.
 	 * This may speed up certain requests, especially with large cards.
 	 *
 	 * @param mixed $addressbookId
@@ -692,11 +667,6 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 		$shares = $this->getShares($addressBookId);
 		$objectRow = $this->getCard($addressBookId, $cardUri);
 		$this->dispatcher->dispatchTyped(new CardCreatedEvent($addressBookId, $addressBookData, $shares, $objectRow));
-		$this->legacyDispatcher->dispatch('\OCA\DAV\CardDAV\CardDavBackend::createCard',
-			new GenericEvent(null, [
-				'addressBookId' => $addressBookId,
-				'cardUri' => $cardUri,
-				'cardData' => $cardData]));
 
 		return '"' . $etag . '"';
 	}
@@ -756,12 +726,6 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 		$shares = $this->getShares($addressBookId);
 		$objectRow = $this->getCard($addressBookId, $cardUri);
 		$this->dispatcher->dispatchTyped(new CardUpdatedEvent($addressBookId, $addressBookData, $shares, $objectRow));
-		$this->legacyDispatcher->dispatch('\OCA\DAV\CardDAV\CardDavBackend::updateCard',
-			new GenericEvent(null, [
-				'addressBookId' => $addressBookId,
-				'cardUri' => $cardUri,
-				'cardData' => $cardData]));
-
 		return '"' . $etag . '"';
 	}
 
@@ -793,11 +757,6 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 		if ($ret === 1) {
 			if ($cardId !== null) {
 				$this->dispatcher->dispatchTyped(new CardDeletedEvent($addressBookId, $addressBookData, $shares, $objectRow));
-				$this->legacyDispatcher->dispatch('\OCA\DAV\CardDAV\CardDavBackend::deleteCard',
-					new GenericEvent(null, [
-						'addressBookId' => $addressBookId,
-						'cardUri' => $cardUri]));
-
 				$this->purgeProperties($addressBookId, $cardId);
 			}
 			return true;
@@ -1002,11 +961,10 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	}
 
 	/**
-	 * @param IShareable $shareable
-	 * @param string[] $add
-	 * @param string[] $remove
+	 * @param list<array{href: string, commonName: string, readOnly: bool}> $add
+	 * @param list<string> $remove
 	 */
-	public function updateShares(IShareable $shareable, $add, $remove) {
+	public function updateShares(IShareable $shareable, array $add, array $remove): void {
 		$addressBookId = $shareable->getResourceId();
 		$addressBookData = $this->getAddressBookById($addressBookId);
 		$oldShares = $this->getShares($addressBookId);
@@ -1237,11 +1195,10 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	 *   * commonName - Optional, for example a first + last name
 	 *   * status - See the Sabre\CalDAV\SharingPlugin::STATUS_ constants.
 	 *   * readOnly - boolean
-	 *   * summary - Optional, a description for the share
 	 *
-	 * @return array
+	 * @return list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}>
 	 */
-	public function getShares($addressBookId) {
+	public function getShares(int $addressBookId): array {
 		return $this->sharingBackend->getShares($addressBookId);
 	}
 
@@ -1321,13 +1278,9 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	}
 
 	/**
-	 * get ID from a given contact
-	 *
-	 * @param int $addressBookId
-	 * @param string $uri
-	 * @return int
+	 * Get ID from a given contact
 	 */
-	protected function getCardId($addressBookId, $uri) {
+	protected function getCardId(int $addressBookId, string $uri): int {
 		$query = $this->db->getQueryBuilder();
 		$query->select('id')->from($this->dbCardsTable)
 			->where($query->expr()->eq('uri', $query->createNamedParameter($uri)))
@@ -1347,15 +1300,15 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	/**
 	 * For shared address books the sharee is set in the ACL of the address book
 	 *
-	 * @param $addressBookId
-	 * @param $acl
-	 * @return array
+	 * @param int $addressBookId
+	 * @param list<array{privilege: string, principal: string, protected: bool}> $acl
+	 * @return list<array{privilege: string, principal: string, protected: bool}>
 	 */
-	public function applyShareAcl($addressBookId, $acl) {
+	public function applyShareAcl(int $addressBookId, array $acl): array {
 		return $this->sharingBackend->applyShareAcl($addressBookId, $acl);
 	}
 
-	private function convertPrincipal($principalUri, $toV2) {
+	private function convertPrincipal(string $principalUri, bool $toV2): string {
 		if ($this->principalBackend->getPrincipalPrefix() === 'principals') {
 			[, $name] = \Sabre\Uri\split($principalUri);
 			if ($toV2 === true) {
@@ -1366,7 +1319,7 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 		return $principalUri;
 	}
 
-	private function addOwnerPrincipal(&$addressbookInfo) {
+	private function addOwnerPrincipal(array &$addressbookInfo): void {
 		$ownerPrincipalKey = '{' . \OCA\DAV\DAV\Sharing\Plugin::NS_OWNCLOUD . '}owner-principal';
 		$displaynameKey = '{' . \OCA\DAV\DAV\Sharing\Plugin::NS_NEXTCLOUD . '}owner-displayname';
 		if (isset($addressbookInfo[$ownerPrincipalKey])) {
@@ -1386,10 +1339,10 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	 *
 	 * @param string $cardData the vcard raw data
 	 * @return string the uid
-	 * @throws BadRequest if no UID is available
+	 * @throws BadRequest if no UID is available or vcard is empty
 	 */
-	private function getUID($cardData) {
-		if ($cardData != '') {
+	private function getUID(string $cardData): string {
+		if ($cardData !== '') {
 			$vCard = Reader::read($cardData);
 			if ($vCard->UID) {
 				$uid = $vCard->UID->getValue();
diff --git a/apps/dav/lib/CardDAV/SyncService.php b/apps/dav/lib/CardDAV/SyncService.php
index 169dbc79e0f..5094b7f3f5c 100644
--- a/apps/dav/lib/CardDAV/SyncService.php
+++ b/apps/dav/lib/CardDAV/SyncService.php
@@ -40,27 +40,13 @@ use Sabre\HTTP\ClientHttpException;
 use Sabre\VObject\Reader;
 
 class SyncService {
-
-	/** @var CardDavBackend */
-	private $backend;
-
-	/** @var IUserManager */
-	private $userManager;
-
+	private CardDavBackend $backend;
+	private IUserManager $userManager;
 	private LoggerInterface $logger;
+	private ?array $localSystemAddressBook = null;
+	private Converter $converter;
+	protected string $certPath;
 
-	/** @var array */
-	private $localSystemAddressBook;
-
-	/** @var Converter */
-	private $converter;
-
-	/** @var string */
-	protected $certPath;
-
-	/**
-	 * SyncService constructor.
-	 */
 	public function __construct(CardDavBackend $backend,
 								IUserManager $userManager,
 								LoggerInterface $logger,
@@ -73,20 +59,11 @@ class SyncService {
 	}
 
 	/**
-	 * @param string $url
-	 * @param string $userName
-	 * @param string $addressBookUrl
-	 * @param string $sharedSecret
-	 * @param string $syncToken
-	 * @param int $targetBookId
-	 * @param string $targetPrincipal
-	 * @param array $targetProperties
-	 * @return string
 	 * @throws \Exception
 	 */
-	public function syncRemoteAddressBook($url, $userName, $addressBookUrl, $sharedSecret, $syncToken, $targetBookId, $targetPrincipal, $targetProperties) {
+	public function syncRemoteAddressBook(string $url, string $userName, string $addressBookUrl, string $sharedSecret, ?string $syncToken, string $targetBookHash, string $targetPrincipal, array $targetProperties): string {
 		// 1. create addressbook
-		$book = $this->ensureSystemAddressBookExists($targetPrincipal, (string)$targetBookId, $targetProperties);
+		$book = $this->ensureSystemAddressBookExists($targetPrincipal, $targetBookHash, $targetProperties);
 		$addressBookId = $book['id'];
 
 		// 2. query changes
@@ -122,28 +99,23 @@ class SyncService {
 	}
 
 	/**
-	 * @param string $principal
-	 * @param string $id
-	 * @param array $properties
-	 * @return array|null
 	 * @throws \Sabre\DAV\Exception\BadRequest
 	 */
-	public function ensureSystemAddressBookExists($principal, $id, $properties) {
-		$book = $this->backend->getAddressBooksByUri($principal, $id);
+	public function ensureSystemAddressBookExists(string $principal, string $uri, array $properties): ?array {
+		$book = $this->backend->getAddressBooksByUri($principal, $uri);
 		if (!is_null($book)) {
 			return $book;
 		}
-		$this->backend->createAddressBook($principal, $id, $properties);
+		// FIXME This might break in clustered DB setup
+		$this->backend->createAddressBook($principal, $uri, $properties);
 
-		return $this->backend->getAddressBooksByUri($principal, $id);
+		return $this->backend->getAddressBooksByUri($principal, $uri);
 	}
 
 	/**
 	 * Check if there is a valid certPath we should use
-	 *
-	 * @return string
 	 */
-	protected function getCertPath() {
+	protected function getCertPath(): string {
 
 		// we already have a valid certPath
 		if ($this->certPath !== '') {
@@ -159,14 +131,7 @@ class SyncService {
 		return $this->certPath;
 	}
 
-	/**
-	 * @param string $url
-	 * @param string $userName
-	 * @param string $addressBookUrl
-	 * @param string $sharedSecret
-	 * @return Client
-	 */
-	protected function getClient($url, $userName, $sharedSecret) {
+	protected function getClient(string $url, string $userName, string $sharedSecret): Client {
 		$settings = [
 			'baseUri' => $url . '/',
 			'userName' => $userName,
@@ -183,15 +148,7 @@ class SyncService {
 		return $client;
 	}
 
-	/**
-	 * @param string $url
-	 * @param string $userName
-	 * @param string $addressBookUrl
-	 * @param string $sharedSecret
-	 * @param string $syncToken
-	 * @return array
-	 */
-	protected function requestSyncReport($url, $userName, $addressBookUrl, $sharedSecret, $syncToken) {
+	protected function requestSyncReport(string $url, string $userName, string $addressBookUrl, string $sharedSecret, ?string $syncToken): array {
 		$client = $this->getClient($url, $userName, $sharedSecret);
 
 		$body = $this->buildSyncCollectionRequestBody($syncToken);
@@ -203,23 +160,12 @@ class SyncService {
 		return $this->parseMultiStatus($response['body']);
 	}
 
-	/**
-	 * @param string $url
-	 * @param string $userName
-	 * @param string $sharedSecret
-	 * @param string $resourcePath
-	 * @return array
-	 */
-	protected function download($url, $userName, $sharedSecret, $resourcePath) {
+	protected function download(string $url, string $userName, string $sharedSecret, string $resourcePath): array {
 		$client = $this->getClient($url, $userName, $sharedSecret);
 		return $client->request('GET', $resourcePath);
 	}
 
-	/**
-	 * @param string|null $syncToken
-	 * @return string
-	 */
-	private function buildSyncCollectionRequestBody($syncToken) {
+	private function buildSyncCollectionRequestBody(?string $syncToken): string {
 		$dom = new \DOMDocument('1.0', 'UTF-8');
 		$dom->formatOutput = true;
 		$root = $dom->createElementNS('DAV:', 'd:sync-collection');
diff --git a/apps/dav/lib/Command/CreateCalendar.php b/apps/dav/lib/Command/CreateCalendar.php
index 2bea82a345e..08f937dff9d 100644
--- a/apps/dav/lib/Command/CreateCalendar.php
+++ b/apps/dav/lib/Command/CreateCalendar.php
@@ -29,6 +29,7 @@ use OC\KnownUser\KnownUserService;
 use OCA\DAV\CalDAV\CalDavBackend;
 use OCA\DAV\CalDAV\Proxy\ProxyMapper;
 use OCA\DAV\Connector\Sabre\Principal;
+use OCP\Accounts\IAccountManager;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\IConfig;
 use OCP\IDBConnection;
@@ -83,6 +84,7 @@ class CreateCalendar extends Command {
 		$principalBackend = new Principal(
 			$this->userManager,
 			$this->groupManager,
+			\OC::$server->get(IAccountManager::class),
 			\OC::$server->getShareManager(),
 			\OC::$server->getUserSession(),
 			\OC::$server->getAppManager(),
@@ -94,7 +96,6 @@ class CreateCalendar extends Command {
 		$random = \OC::$server->getSecureRandom();
 		$logger = \OC::$server->get(LoggerInterface::class);
 		$dispatcher = \OC::$server->get(IEventDispatcher::class);
-		$legacyDispatcher = \OC::$server->getEventDispatcher();
 		$config = \OC::$server->get(IConfig::class);
 
 		$name = $input->getArgument('name');
@@ -106,7 +107,6 @@ class CreateCalendar extends Command {
 			$random,
 			$logger,
 			$dispatcher,
-			$legacyDispatcher,
 			$config
 		);
 		$caldav->createCalendar("principals/users/$user", $name, []);
diff --git a/apps/dav/lib/Command/MoveCalendar.php b/apps/dav/lib/Command/MoveCalendar.php
index 320fe8aeac6..9272b20b10d 100644
--- a/apps/dav/lib/Command/MoveCalendar.php
+++ b/apps/dav/lib/Command/MoveCalendar.php
@@ -42,41 +42,17 @@ use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Console\Style\SymfonyStyle;
 
 class MoveCalendar extends Command {
-
-	/** @var IUserManager */
-	private $userManager;
-
-	/** @var IGroupManager */
-	private $groupManager;
-
-	/** @var IShareManager */
-	private $shareManager;
-
-	/** @var IConfig $config */
-	private $config;
-
-	/** @var IL10N */
-	private $l10n;
-
-	/** @var SymfonyStyle */
-	private $io;
-
-	/** @var CalDavBackend */
-	private $calDav;
-
-	/** @var LoggerInterface */
-	private $logger;
+	private IUserManager $userManager;
+	private IGroupManager $groupManager;
+	private IShareManager $shareManager;
+	private IConfig $config;
+	private IL10N $l10n;
+	private ?SymfonyStyle $io = null;
+	private CalDavBackend $calDav;
+	private LoggerInterface $logger;
 
 	public const URI_USERS = 'principals/users/';
 
-	/**
-	 * @param IUserManager $userManager
-	 * @param IGroupManager $groupManager
-	 * @param IShareManager $shareManager
-	 * @param IConfig $config
-	 * @param IL10N $l10n
-	 * @param CalDavBackend $calDav
-	 */
 	public function __construct(
 		IUserManager $userManager,
 		IGroupManager $groupManager,
@@ -224,7 +200,7 @@ class MoveCalendar extends Command {
 			 */
 			if ($this->shareManager->shareWithGroupMembersOnly() === true && 'groups' === $prefix && !$this->groupManager->isInGroup($userDestination, $userOrGroup)) {
 				if ($force) {
-					$this->calDav->updateShares(new Calendar($this->calDav, $calendar, $this->l10n, $this->config, $this->logger), [], ['href' => 'principal:principals/groups/' . $userOrGroup]);
+					$this->calDav->updateShares(new Calendar($this->calDav, $calendar, $this->l10n, $this->config, $this->logger), [], ['principal:principals/groups/' . $userOrGroup]);
 				} else {
 					throw new \InvalidArgumentException("User <$userDestination> is not part of the group <$userOrGroup> with whom the calendar <" . $calendar['uri'] . "> was shared. You may use -f to move the calendar while deleting this share.");
 				}
@@ -235,7 +211,7 @@ class MoveCalendar extends Command {
 			 */
 			if ($userOrGroup === $userDestination) {
 				if ($force) {
-					$this->calDav->updateShares(new Calendar($this->calDav, $calendar, $this->l10n, $this->config, $this->logger), [], ['href' => 'principal:principals/users/' . $userOrGroup]);
+					$this->calDav->updateShares(new Calendar($this->calDav, $calendar, $this->l10n, $this->config, $this->logger), [], ['principal:principals/users/' . $userOrGroup]);
 				} else {
 					throw new \InvalidArgumentException("The calendar <" . $calendar['uri'] . "> is already shared to user <$userDestination>.You may use -f to move the calendar while deleting this share.");
 				}
diff --git a/apps/dav/lib/Connector/Sabre/ChecksumList.php b/apps/dav/lib/Connector/Sabre/ChecksumList.php
index 344e6a4ab3c..44573de03c8 100644
--- a/apps/dav/lib/Connector/Sabre/ChecksumList.php
+++ b/apps/dav/lib/Connector/Sabre/ChecksumList.php
@@ -42,7 +42,7 @@ class ChecksumList implements XmlSerializable {
 	}
 
 	/**
-	 * The xmlSerialize metod is called during xml writing.
+	 * The xmlSerialize method is called during xml writing.
 	 *
 	 * Use the $writer argument to write its own xml serialization.
 	 *
diff --git a/apps/dav/lib/Connector/Sabre/Directory.php b/apps/dav/lib/Connector/Sabre/Directory.php
index 5280511d5be..b575a051b2a 100644
--- a/apps/dav/lib/Connector/Sabre/Directory.php
+++ b/apps/dav/lib/Connector/Sabre/Directory.php
@@ -66,7 +66,7 @@ class Directory extends \OCA\DAV\Connector\Sabre\Node implements \Sabre\DAV\ICol
 
 	/** Cached quota info */
 	private ?array $quotaInfo = null;
-	private ?ObjectTree $tree = null;
+	private ?CachingTree $tree = null;
 
 	/** @var array<string, array<int, FileMetadata>> */
 	private array $metadata = [];
@@ -74,7 +74,7 @@ class Directory extends \OCA\DAV\Connector\Sabre\Node implements \Sabre\DAV\ICol
 	/**
 	 * Sets up the node, expects a full path name
 	 */
-	public function __construct(View $view, FileInfo $info, ?ObjectTree $tree = null, IShareManager $shareManager = null) {
+	public function __construct(View $view, FileInfo $info, ?CachingTree $tree = null, IShareManager $shareManager = null) {
 		parent::__construct($view, $info, $shareManager);
 		$this->tree = $tree;
 	}
diff --git a/apps/dav/lib/Connector/Sabre/ExceptionLoggerPlugin.php b/apps/dav/lib/Connector/Sabre/ExceptionLoggerPlugin.php
index ea94b5c8933..ebf3e4021eb 100644
--- a/apps/dav/lib/Connector/Sabre/ExceptionLoggerPlugin.php
+++ b/apps/dav/lib/Connector/Sabre/ExceptionLoggerPlugin.php
@@ -29,6 +29,7 @@ namespace OCA\DAV\Connector\Sabre;
 
 use OCA\DAV\Connector\Sabre\Exception\FileLocked;
 use OCA\DAV\Connector\Sabre\Exception\PasswordLoginForbidden;
+use OCA\DAV\Exception\ServerMaintenanceMode;
 use OCP\Files\StorageNotAvailableException;
 use Psr\Log\LoggerInterface;
 use Sabre\DAV\Exception\BadRequest;
@@ -81,6 +82,7 @@ class ExceptionLoggerPlugin extends \Sabre\DAV\ServerPlugin {
 		FileLocked::class => true,
 		// An invalid range is requested
 		RequestedRangeNotSatisfiable::class => true,
+		ServerMaintenanceMode::class => true,
 	];
 
 	private string $appName;
@@ -114,17 +116,12 @@ class ExceptionLoggerPlugin extends \Sabre\DAV\ServerPlugin {
 	 */
 	public function logException(\Throwable $ex) {
 		$exceptionClass = get_class($ex);
-		if (isset($this->nonFatalExceptions[$exceptionClass]) ||
-			(
-				$exceptionClass === ServiceUnavailable::class &&
-				$ex->getMessage() === 'System in maintenance mode.'
-			)
-		) {
+		if (isset($this->nonFatalExceptions[$exceptionClass])) {
 			$this->logger->debug($ex->getMessage(), [
 				'app' => $this->appName,
 				'exception' => $ex,
 			]);
-			return; 
+			return;
 		}
 
 		$this->logger->critical($ex->getMessage(), [
diff --git a/apps/dav/lib/Connector/Sabre/File.php b/apps/dav/lib/Connector/Sabre/File.php
index ebcfdabc6b3..94632b265db 100644
--- a/apps/dav/lib/Connector/Sabre/File.php
+++ b/apps/dav/lib/Connector/Sabre/File.php
@@ -553,7 +553,7 @@ class File extends Node implements IFile {
 	 * @return array|bool
 	 */
 	public function getDirectDownload() {
-		if (\OCP\App::isEnabled('encryption')) {
+		if (\OCP\Server::get(\OCP\App\IAppManager::class)->isEnabledForUser('encryption')) {
 			return [];
 		}
 		/** @var \OCP\Files\Storage $storage */
diff --git a/apps/dav/lib/Connector/Sabre/FilesPlugin.php b/apps/dav/lib/Connector/Sabre/FilesPlugin.php
index b784764f8fe..e9d27d4e7f6 100644
--- a/apps/dav/lib/Connector/Sabre/FilesPlugin.php
+++ b/apps/dav/lib/Connector/Sabre/FilesPlugin.php
@@ -65,6 +65,7 @@ class FilesPlugin extends ServerPlugin {
 	public const PERMISSIONS_PROPERTYNAME = '{http://owncloud.org/ns}permissions';
 	public const SHARE_PERMISSIONS_PROPERTYNAME = '{http://open-collaboration-services.org/ns}share-permissions';
 	public const OCM_SHARE_PERMISSIONS_PROPERTYNAME = '{http://open-cloud-mesh.org/ns}share-permissions';
+	public const SHARE_ATTRIBUTES_PROPERTYNAME = '{http://nextcloud.org/ns}share-attributes';
 	public const DOWNLOADURL_PROPERTYNAME = '{http://owncloud.org/ns}downloadURL';
 	public const SIZE_PROPERTYNAME = '{http://owncloud.org/ns}size';
 	public const GETETAG_PROPERTYNAME = '{DAV:}getetag';
@@ -134,6 +135,7 @@ class FilesPlugin extends ServerPlugin {
 		$server->protectedProperties[] = self::PERMISSIONS_PROPERTYNAME;
 		$server->protectedProperties[] = self::SHARE_PERMISSIONS_PROPERTYNAME;
 		$server->protectedProperties[] = self::OCM_SHARE_PERMISSIONS_PROPERTYNAME;
+		$server->protectedProperties[] = self::SHARE_ATTRIBUTES_PROPERTYNAME;
 		$server->protectedProperties[] = self::SIZE_PROPERTYNAME;
 		$server->protectedProperties[] = self::DOWNLOADURL_PROPERTYNAME;
 		$server->protectedProperties[] = self::OWNER_ID_PROPERTYNAME;
@@ -321,6 +323,10 @@ class FilesPlugin extends ServerPlugin {
 				return json_encode($ocmPermissions);
 			});
 
+			$propFind->handle(self::SHARE_ATTRIBUTES_PROPERTYNAME, function () use ($node, $httpRequest) {
+				return json_encode($node->getShareAttributes());
+			});
+
 			$propFind->handle(self::GETETAG_PROPERTYNAME, function () use ($node): string {
 				return $node->getETag();
 			});
diff --git a/apps/dav/lib/Connector/Sabre/MaintenancePlugin.php b/apps/dav/lib/Connector/Sabre/MaintenancePlugin.php
index e7e3b273b98..1fc02320805 100644
--- a/apps/dav/lib/Connector/Sabre/MaintenancePlugin.php
+++ b/apps/dav/lib/Connector/Sabre/MaintenancePlugin.php
@@ -27,6 +27,7 @@
  */
 namespace OCA\DAV\Connector\Sabre;
 
+use OCA\DAV\Exception\ServerMaintenanceMode;
 use OCP\IConfig;
 use OCP\IL10N;
 use OCP\Util;
@@ -82,10 +83,10 @@ class MaintenancePlugin extends ServerPlugin {
 	 */
 	public function checkMaintenanceMode() {
 		if ($this->config->getSystemValueBool('maintenance')) {
-			throw new ServiceUnavailable($this->l10n->t('System is in maintenance mode.'));
+			throw new ServerMaintenanceMode($this->l10n->t('System is in maintenance mode.'));
 		}
 		if (Util::needUpgrade()) {
-			throw new ServiceUnavailable($this->l10n->t('Upgrade needed'));
+			throw new ServerMaintenanceMode($this->l10n->t('Upgrade needed'));
 		}
 
 		return true;
diff --git a/apps/dav/lib/Connector/Sabre/Node.php b/apps/dav/lib/Connector/Sabre/Node.php
index e4517068f42..87f2fea394f 100644
--- a/apps/dav/lib/Connector/Sabre/Node.php
+++ b/apps/dav/lib/Connector/Sabre/Node.php
@@ -38,6 +38,7 @@ namespace OCA\DAV\Connector\Sabre;
 use OC\Files\Mount\MoveableMount;
 use OC\Files\Node\File;
 use OC\Files\Node\Folder;
+use OC\Files\Storage\Wrapper\Wrapper;
 use OC\Files\View;
 use OCA\DAV\Connector\Sabre\Exception\InvalidPath;
 use OCP\Files\FileInfo;
@@ -323,6 +324,31 @@ abstract class Node implements \Sabre\DAV\INode {
 	}
 
 	/**
+	 * @return array
+	 */
+	public function getShareAttributes(): array {
+		$attributes = [];
+
+		try {
+			$storage = $this->info->getStorage();
+		} catch (StorageNotAvailableException $e) {
+			$storage = null;
+		}
+
+		if ($storage && $storage->instanceOfStorage(\OCA\Files_Sharing\SharedStorage::class)) {
+			/** @var \OCA\Files_Sharing\SharedStorage $storage */
+			$attributes = $storage->getShare()->getAttributes();
+			if ($attributes === null) {
+				return [];
+			} else {
+				return $attributes->toArray();
+			}
+		}
+
+		return $attributes;
+	}
+
+	/**
 	 * @param string $user
 	 * @return string
 	 */
diff --git a/apps/dav/lib/Connector/Sabre/Principal.php b/apps/dav/lib/Connector/Sabre/Principal.php
index 94e3978e67d..75bee4e7b42 100644
--- a/apps/dav/lib/Connector/Sabre/Principal.php
+++ b/apps/dav/lib/Connector/Sabre/Principal.php
@@ -41,6 +41,9 @@ use OC\KnownUser\KnownUserService;
 use OCA\Circles\Exceptions\CircleNotFoundException;
 use OCA\DAV\CalDAV\Proxy\ProxyMapper;
 use OCA\DAV\Traits\PrincipalProxyTrait;
+use OCP\Accounts\IAccountManager;
+use OCP\Accounts\IAccountProperty;
+use OCP\Accounts\PropertyDoesNotExistException;
 use OCP\App\IAppManager;
 use OCP\AppFramework\QueryException;
 use OCP\Constants;
@@ -64,6 +67,9 @@ class Principal implements BackendInterface {
 	/** @var IGroupManager */
 	private $groupManager;
 
+	/** @var IAccountManager */
+	private $accountManager;
+
 	/** @var IShareManager */
 	private $shareManager;
 
@@ -95,6 +101,7 @@ class Principal implements BackendInterface {
 
 	public function __construct(IUserManager $userManager,
 								IGroupManager $groupManager,
+								IAccountManager $accountManager,
 								IShareManager $shareManager,
 								IUserSession $userSession,
 								IAppManager $appManager,
@@ -105,6 +112,7 @@ class Principal implements BackendInterface {
 								string $principalPrefix = 'principals/users/') {
 		$this->userManager = $userManager;
 		$this->groupManager = $groupManager;
+		$this->accountManager = $accountManager;
 		$this->shareManager = $shareManager;
 		$this->userSession = $userSession;
 		$this->appManager = $appManager;
@@ -506,6 +514,7 @@ class Principal implements BackendInterface {
 	/**
 	 * @param IUser $user
 	 * @return array
+	 * @throws PropertyDoesNotExistException
 	 */
 	protected function userToPrincipal($user) {
 		$userId = $user->getUID();
@@ -517,11 +526,18 @@ class Principal implements BackendInterface {
 			'{http://nextcloud.com/ns}language' => $this->languageFactory->getUserLanguage($user),
 		];
 
+		$account = $this->accountManager->getAccount($user);
+		$alternativeEmails = array_map(fn (IAccountProperty $property) => 'mailto:' . $property->getValue(), $account->getPropertyCollection(IAccountManager::COLLECTION_EMAIL)->getProperties());
+
 		$email = $user->getSystemEMailAddress();
 		if (!empty($email)) {
 			$principal['{http://sabredav.org/ns}email-address'] = $email;
 		}
 
+		if (!empty($alternativeEmails)) {
+			$principal['{DAV:}alternate-URI-set'] = $alternativeEmails;
+		}
+
 		return $principal;
 	}
 
diff --git a/apps/dav/lib/Connector/Sabre/ServerFactory.php b/apps/dav/lib/Connector/Sabre/ServerFactory.php
index 8f1f710ca5e..4c57f3412e3 100644
--- a/apps/dav/lib/Connector/Sabre/ServerFactory.php
+++ b/apps/dav/lib/Connector/Sabre/ServerFactory.php
@@ -33,6 +33,7 @@ namespace OCA\DAV\Connector\Sabre;
 
 use OCP\Files\Folder;
 use OCA\DAV\AppInfo\PluginManager;
+use OCA\DAV\DAV\ViewOnlyPlugin;
 use OCA\DAV\Files\BrowserErrorPagePlugin;
 use OCP\Files\Mount\IMountManager;
 use OCP\IConfig;
@@ -158,6 +159,11 @@ class ServerFactory {
 			$server->addPlugin(new \OCA\DAV\Connector\Sabre\QuotaPlugin($view, true));
 			$server->addPlugin(new \OCA\DAV\Connector\Sabre\ChecksumUpdatePlugin());
 
+			// Allow view-only plugin for webdav requests
+			$server->addPlugin(new ViewOnlyPlugin(
+				$this->logger
+			));
+
 			if ($this->userSession->isLoggedIn()) {
 				$server->addPlugin(new \OCA\DAV\Connector\Sabre\TagsPlugin($objectTree, $this->tagManager));
 				$server->addPlugin(new \OCA\DAV\Connector\Sabre\SharesPlugin(
diff --git a/apps/dav/lib/Connector/Sabre/ShareTypeList.php b/apps/dav/lib/Connector/Sabre/ShareTypeList.php
index 6fbae0dee4a..bacbdc99a73 100644
--- a/apps/dav/lib/Connector/Sabre/ShareTypeList.php
+++ b/apps/dav/lib/Connector/Sabre/ShareTypeList.php
@@ -79,7 +79,7 @@ class ShareTypeList implements Element {
 	}
 
 	/**
-	 * The xmlSerialize metod is called during xml writing.
+	 * The xmlSerialize method is called during xml writing.
 	 *
 	 * @param Writer $writer
 	 * @return void
diff --git a/apps/dav/lib/Connector/Sabre/ShareeList.php b/apps/dav/lib/Connector/Sabre/ShareeList.php
index db8c011cc45..e43f552a8cc 100644
--- a/apps/dav/lib/Connector/Sabre/ShareeList.php
+++ b/apps/dav/lib/Connector/Sabre/ShareeList.php
@@ -45,7 +45,7 @@ class ShareeList implements XmlSerializable {
 	}
 
 	/**
-	 * The xmlSerialize metod is called during xml writing.
+	 * The xmlSerialize method is called during xml writing.
 	 *
 	 * @param Writer $writer
 	 * @return void
diff --git a/apps/dav/lib/Connector/Sabre/TagList.php b/apps/dav/lib/Connector/Sabre/TagList.php
index bbb938fb27d..86006cd3404 100644
--- a/apps/dav/lib/Connector/Sabre/TagList.php
+++ b/apps/dav/lib/Connector/Sabre/TagList.php
@@ -95,7 +95,7 @@ class TagList implements Element {
 	}
 
 	/**
-	 * The xmlSerialize metod is called during xml writing.
+	 * The xmlSerialize method is called during xml writing.
 	 *
 	 * Use the $writer argument to write its own xml serialization.
 	 *
diff --git a/apps/dav/lib/Controller/DirectController.php b/apps/dav/lib/Controller/DirectController.php
index 955400998cf..f9c83488935 100644
--- a/apps/dav/lib/Controller/DirectController.php
+++ b/apps/dav/lib/Controller/DirectController.php
@@ -31,8 +31,12 @@ use OCA\DAV\Db\DirectMapper;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\AppFramework\OCS\OCSBadRequestException;
 use OCP\AppFramework\OCS\OCSNotFoundException;
+use OCP\AppFramework\OCS\OCSForbiddenException;
 use OCP\AppFramework\OCSController;
 use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\EventDispatcher\GenericEvent;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\Files\Events\BeforeDirectFileDownloadEvent;
 use OCP\Files\File;
 use OCP\Files\IRootFolder;
 use OCP\IRequest;
@@ -59,6 +63,8 @@ class DirectController extends OCSController {
 	/** @var IURLGenerator */
 	private $urlGenerator;
 
+	/** @var IEventDispatcher */
+	private $eventDispatcher;
 
 	public function __construct(string $appName,
 								IRequest $request,
@@ -67,7 +73,8 @@ class DirectController extends OCSController {
 								DirectMapper $mapper,
 								ISecureRandom $random,
 								ITimeFactory $timeFactory,
-								IURLGenerator $urlGenerator) {
+								IURLGenerator $urlGenerator,
+								IEventDispatcher $eventDispatcher) {
 		parent::__construct($appName, $request);
 
 		$this->rootFolder = $rootFolder;
@@ -76,6 +83,7 @@ class DirectController extends OCSController {
 		$this->random = $random;
 		$this->timeFactory = $timeFactory;
 		$this->urlGenerator = $urlGenerator;
+		$this->eventDispatcher = $eventDispatcher;
 	}
 
 	/**
@@ -99,6 +107,13 @@ class DirectController extends OCSController {
 			throw new OCSBadRequestException('Direct download only works for files');
 		}
 
+		$event = new BeforeDirectFileDownloadEvent($userFolder->getRelativePath($file->getPath()));
+		$this->eventDispatcher->dispatchTyped($event);
+
+		if ($event->isSuccessful() === false) {
+			throw new OCSForbiddenException('Permission denied to download file');
+		}
+
 		//TODO: at some point we should use the directdownlaod function of storages
 		$direct = new Direct();
 		$direct->setUserId($this->userId);
diff --git a/apps/dav/lib/DAV/CustomPropertiesBackend.php b/apps/dav/lib/DAV/CustomPropertiesBackend.php
index acee65cd00d..0110990a408 100644
--- a/apps/dav/lib/DAV/CustomPropertiesBackend.php
+++ b/apps/dav/lib/DAV/CustomPropertiesBackend.php
@@ -24,13 +24,15 @@
  */
 namespace OCA\DAV\DAV;
 
-use OCA\DAV\Connector\Sabre\Node;
+use Exception;
+use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\IDBConnection;
 use OCP\IUser;
 use Sabre\DAV\PropertyStorage\Backend\BackendInterface;
 use Sabre\DAV\PropFind;
 use Sabre\DAV\PropPatch;
 use Sabre\DAV\Tree;
+use Sabre\DAV\Xml\Property\Complex;
 use function array_intersect;
 
 class CustomPropertiesBackend implements BackendInterface {
@@ -39,6 +41,21 @@ class CustomPropertiesBackend implements BackendInterface {
 	private const TABLE_NAME = 'properties';
 
 	/**
+	 * Value is stored as string.
+	 */
+	public const PROPERTY_TYPE_STRING = 1;
+
+	/**
+	 * Value is stored as XML fragment.
+	 */
+	public const PROPERTY_TYPE_XML = 2;
+
+	/**
+	 * Value is stored as a property object.
+	 */
+	public const PROPERTY_TYPE_OBJECT = 3;
+
+	/**
 	 * Ignored properties
 	 *
 	 * @var string[]
@@ -239,7 +256,7 @@ class CustomPropertiesBackend implements BackendInterface {
 		$result = $qb->executeQuery();
 		$props = [];
 		while ($row = $result->fetch()) {
-			$props[$row['propertyname']] = $row['propertyvalue'];
+			$props[$row['propertyname']] = $this->decodeValueFromDatabase($row['propertyvalue'], $row['valuetype']);
 		}
 		$result->closeCursor();
 		return $props;
@@ -282,7 +299,7 @@ class CustomPropertiesBackend implements BackendInterface {
 
 		$props = [];
 		while ($row = $result->fetch()) {
-			$props[$row['propertyname']] = $row['propertyvalue'];
+			$props[$row['propertyname']] = $this->decodeValueFromDatabase($row['propertyvalue'], $row['valuetype']);
 		}
 
 		$result->closeCursor();
@@ -292,68 +309,54 @@ class CustomPropertiesBackend implements BackendInterface {
 	}
 
 	/**
-	 * Update properties
-	 *
-	 * @param string $path path for which to update properties
-	 * @param array $properties array of properties to update
-	 *
-	 * @return bool
+	 * @throws Exception
 	 */
-	private function updateProperties(string $path, array $properties) {
-		$deleteStatement = 'DELETE FROM `*PREFIX*properties`' .
-			' WHERE `userid` = ? AND `propertypath` = ? AND `propertyname` = ?';
-
-		$insertStatement = 'INSERT INTO `*PREFIX*properties`' .
-			' (`userid`,`propertypath`,`propertyname`,`propertyvalue`) VALUES(?,?,?,?)';
-
-		$updateStatement = 'UPDATE `*PREFIX*properties` SET `propertyvalue` = ?' .
-			' WHERE `userid` = ? AND `propertypath` = ? AND `propertyname` = ?';
-
+	private function updateProperties(string $path, array $properties): bool {
 		// TODO: use "insert or update" strategy ?
 		$existing = $this->getUserProperties($path, []);
-		$this->connection->beginTransaction();
-		foreach ($properties as $propertyName => $propertyValue) {
-			// If it was null, we need to delete the property
-			if (is_null($propertyValue)) {
-				if (array_key_exists($propertyName, $existing)) {
-					$this->connection->executeUpdate($deleteStatement,
-						[
-							$this->user->getUID(),
-							$this->formatPath($path),
-							$propertyName,
-						]
-					);
-				}
-			} else {
-				if ($propertyValue instanceOf \Sabre\DAV\Xml\Property\Complex) {
-					$propertyValue = $propertyValue->getXml();
-				} elseif (!is_string($propertyValue)) {
-					$propertyValue = (string)$propertyValue;
-				}
-				if (!array_key_exists($propertyName, $existing)) {
-					$this->connection->executeUpdate($insertStatement,
-						[
-							$this->user->getUID(),
-							$this->formatPath($path),
-							$propertyName,
-							$propertyValue,
-						]
-					);
+		try {
+			$this->connection->beginTransaction();
+			foreach ($properties as $propertyName => $propertyValue) {
+				// common parameters for all queries
+				$dbParameters = [
+					'userid' => $this->user->getUID(),
+					'propertyPath' => $this->formatPath($path),
+					'propertyName' => $propertyName
+				];
+
+				// If it was null, we need to delete the property
+				if (is_null($propertyValue)) {
+					if (array_key_exists($propertyName, $existing)) {
+						$deleteQuery = $deleteQuery ?? $this->createDeleteQuery();
+						$deleteQuery
+							->setParameters($dbParameters)
+							->executeStatement();
+					}
 				} else {
-					$this->connection->executeUpdate($updateStatement,
-						[
-							$propertyValue,
-							$this->user->getUID(),
-							$this->formatPath($path),
-							$propertyName,
-						]
-					);
+					[$value, $valueType] = $this->encodeValueForDatabase($propertyValue);
+					$dbParameters['propertyValue'] = $value;
+					$dbParameters['valueType'] = $valueType;
+
+					if (!array_key_exists($propertyName, $existing)) {
+						$insertQuery = $insertQuery ?? $this->createInsertQuery();
+						$insertQuery
+							->setParameters($dbParameters)
+							->executeStatement();
+					} else {
+						$updateQuery = $updateQuery ?? $this->createUpdateQuery();
+						$updateQuery
+							->setParameters($dbParameters)
+							->executeStatement();
+					}
 				}
 			}
-		}
 
-		$this->connection->commit();
-		unset($this->userCache[$path]);
+			$this->connection->commit();
+			unset($this->userCache[$path]);
+		} catch (Exception $e) {
+			$this->connection->rollBack();
+			throw $e;
+		}
 
 		return true;
 	}
@@ -367,8 +370,73 @@ class CustomPropertiesBackend implements BackendInterface {
 	private function formatPath(string $path): string {
 		if (strlen($path) > 250) {
 			return sha1($path);
+		}
+
+		return $path;
+	}
+
+	/**
+	 * @param mixed $value
+	 * @return array
+	 */
+	private function encodeValueForDatabase($value): array {
+		if (is_scalar($value)) {
+			$valueType = self::PROPERTY_TYPE_STRING;
+		} elseif ($value instanceof Complex) {
+			$valueType = self::PROPERTY_TYPE_XML;
+			$value = $value->getXml();
 		} else {
-			return $path;
+			$valueType = self::PROPERTY_TYPE_OBJECT;
+			$value = serialize($value);
+		}
+		return [$value, $valueType];
+	}
+
+	/**
+	 * @return mixed|Complex|string
+	 */
+	private function decodeValueFromDatabase(string $value, int $valueType) {
+		switch ($valueType) {
+			case self::PROPERTY_TYPE_XML:
+				return new Complex($value);
+			case self::PROPERTY_TYPE_OBJECT:
+				return unserialize($value);
+			case self::PROPERTY_TYPE_STRING:
+			default:
+				return $value;
 		}
 	}
+
+	private function createDeleteQuery(): IQueryBuilder {
+		$deleteQuery = $this->connection->getQueryBuilder();
+		$deleteQuery->delete('properties')
+			->where($deleteQuery->expr()->eq('userid', $deleteQuery->createParameter('userid')))
+			->andWhere($deleteQuery->expr()->eq('propertypath', $deleteQuery->createParameter('propertyPath')))
+			->andWhere($deleteQuery->expr()->eq('propertyname', $deleteQuery->createParameter('propertyName')));
+		return $deleteQuery;
+	}
+
+	private function createInsertQuery(): IQueryBuilder {
+		$insertQuery = $this->connection->getQueryBuilder();
+		$insertQuery->insert('properties')
+			->values([
+				'userid' => $insertQuery->createParameter('userid'),
+				'propertypath' => $insertQuery->createParameter('propertyPath'),
+				'propertyname' => $insertQuery->createParameter('propertyName'),
+				'propertyvalue' => $insertQuery->createParameter('propertyValue'),
+				'valuetype' => $insertQuery->createParameter('valueType'),
+			]);
+		return $insertQuery;
+	}
+
+	private function createUpdateQuery(): IQueryBuilder {
+		$updateQuery = $this->connection->getQueryBuilder();
+		$updateQuery->update('properties')
+			->set('propertyvalue', $updateQuery->createParameter('propertyValue'))
+			->set('valuetype', $updateQuery->createParameter('valueType'))
+			->where($updateQuery->expr()->eq('userid', $updateQuery->createParameter('userid')))
+			->andWhere($updateQuery->expr()->eq('propertypath', $updateQuery->createParameter('propertyPath')))
+			->andWhere($updateQuery->expr()->eq('propertyname', $updateQuery->createParameter('propertyName')));
+		return $updateQuery;
+	}
 }
diff --git a/apps/dav/lib/DAV/Sharing/Backend.php b/apps/dav/lib/DAV/Sharing/Backend.php
index 0f675ea4c15..90d2c7ebf82 100644
--- a/apps/dav/lib/DAV/Sharing/Backend.php
+++ b/apps/dav/lib/DAV/Sharing/Backend.php
@@ -32,32 +32,20 @@ use OCA\DAV\Connector\Sabre\Principal;
 use OCP\IDBConnection;
 use OCP\IGroupManager;
 use OCP\IUserManager;
+use OCP\DB\QueryBuilder\IQueryBuilder;
 
 class Backend {
-
-	/** @var IDBConnection */
-	private $db;
-	/** @var IUserManager */
-	private $userManager;
-	/** @var IGroupManager */
-	private $groupManager;
-	/** @var Principal */
-	private $principalBackend;
-	/** @var string */
-	private $resourceType;
+	private IDBConnection $db;
+	private IUserManager $userManager;
+	private IGroupManager $groupManager;
+	private Principal $principalBackend;
+	private string $resourceType;
 
 	public const ACCESS_OWNER = 1;
 	public const ACCESS_READ_WRITE = 2;
 	public const ACCESS_READ = 3;
 
-	/**
-	 * @param IDBConnection $db
-	 * @param IUserManager $userManager
-	 * @param IGroupManager $groupManager
-	 * @param Principal $principalBackend
-	 * @param string $resourceType
-	 */
-	public function __construct(IDBConnection $db, IUserManager $userManager, IGroupManager $groupManager, Principal $principalBackend, $resourceType) {
+	public function __construct(IDBConnection $db, IUserManager $userManager, IGroupManager $groupManager, Principal $principalBackend, string $resourceType) {
 		$this->db = $db;
 		$this->userManager = $userManager;
 		$this->groupManager = $groupManager;
@@ -66,11 +54,10 @@ class Backend {
 	}
 
 	/**
-	 * @param IShareable $shareable
-	 * @param string[] $add
-	 * @param string[] $remove
+	 * @param list<array{href: string, commonName: string, readOnly: bool}> $add
+	 * @param list<string> $remove
 	 */
-	public function updateShares(IShareable $shareable, array $add, array $remove) {
+	public function updateShares(IShareable $shareable, array $add, array $remove): void {
 		foreach ($add as $element) {
 			$principal = $this->principalBackend->findByUri($element['href'], '');
 			if ($principal !== '') {
@@ -86,10 +73,9 @@ class Backend {
 	}
 
 	/**
-	 * @param IShareable $shareable
-	 * @param string $element
+	 * @param array{href: string, commonName: string, readOnly: bool} $element
 	 */
-	private function shareWith($shareable, $element) {
+	private function shareWith(IShareable $shareable, array $element): void {
 		$user = $element['href'];
 		$parts = explode(':', $user, 2);
 		if ($parts[0] !== 'principal') {
@@ -129,33 +115,26 @@ class Backend {
 				'access' => $query->createNamedParameter($access),
 				'resourceid' => $query->createNamedParameter($shareable->getResourceId())
 			]);
-		$query->execute();
+		$query->executeStatement();
 	}
 
-	/**
-	 * @param $resourceId
-	 */
-	public function deleteAllShares($resourceId) {
+	public function deleteAllShares(int $resourceId): void {
 		$query = $this->db->getQueryBuilder();
 		$query->delete('dav_shares')
 			->where($query->expr()->eq('resourceid', $query->createNamedParameter($resourceId)))
 			->andWhere($query->expr()->eq('type', $query->createNamedParameter($this->resourceType)))
-			->execute();
+			->executeStatement();
 	}
 
-	public function deleteAllSharesByUser($principaluri) {
+	public function deleteAllSharesByUser(string $principaluri): void {
 		$query = $this->db->getQueryBuilder();
 		$query->delete('dav_shares')
 			->where($query->expr()->eq('principaluri', $query->createNamedParameter($principaluri)))
 			->andWhere($query->expr()->eq('type', $query->createNamedParameter($this->resourceType)))
-			->execute();
+			->executeStatement();
 	}
 
-	/**
-	 * @param IShareable $shareable
-	 * @param string $element
-	 */
-	private function unshare($shareable, $element) {
+	private function unshare(IShareable $shareable, string $element): void {
 		$parts = explode(':', $element, 2);
 		if ($parts[0] !== 'principal') {
 			return;
@@ -172,7 +151,7 @@ class Backend {
 			->andWhere($query->expr()->eq('type', $query->createNamedParameter($this->resourceType)))
 			->andWhere($query->expr()->eq('principaluri', $query->createNamedParameter($parts[1])))
 		;
-		$query->execute();
+		$query->executeStatement();
 	}
 
 	/**
@@ -183,29 +162,28 @@ class Backend {
 	 *   * commonName - Optional, for example a first + last name
 	 *   * status - See the Sabre\CalDAV\SharingPlugin::STATUS_ constants.
 	 *   * readOnly - boolean
-	 *   * summary - Optional, a description for the share
 	 *
 	 * @param int $resourceId
-	 * @return array
+	 * @return list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}>
 	 */
-	public function getShares($resourceId) {
+	public function getShares(int $resourceId): array {
 		$query = $this->db->getQueryBuilder();
 		$result = $query->select(['principaluri', 'access'])
 			->from('dav_shares')
-			->where($query->expr()->eq('resourceid', $query->createNamedParameter($resourceId)))
+			->where($query->expr()->eq('resourceid', $query->createNamedParameter($resourceId, IQueryBuilder::PARAM_INT)))
 			->andWhere($query->expr()->eq('type', $query->createNamedParameter($this->resourceType)))
 			->groupBy(['principaluri', 'access'])
-			->execute();
+			->executeQuery();
 
 		$shares = [];
 		while ($row = $result->fetch()) {
 			$p = $this->principalBackend->getPrincipalByPath($row['principaluri']);
 			$shares[] = [
-				'href' => "principal:${row['principaluri']}",
-				'commonName' => isset($p['{DAV:}displayname']) ? $p['{DAV:}displayname'] : '',
+				'href' => "principal:{$row['principaluri']}",
+				'commonName' => isset($p['{DAV:}displayname']) ? (string)$p['{DAV:}displayname'] : '',
 				'status' => 1,
 				'readOnly' => (int) $row['access'] === self::ACCESS_READ,
-				'{http://owncloud.org/ns}principal' => $row['principaluri'],
+				'{http://owncloud.org/ns}principal' => (string)$row['principaluri'],
 				'{http://owncloud.org/ns}group-share' => is_null($p)
 			];
 		}
@@ -217,10 +195,10 @@ class Backend {
 	 * For shared resources the sharee is set in the ACL of the resource
 	 *
 	 * @param int $resourceId
-	 * @param array $acl
-	 * @return array
+	 * @param list<array{privilege: string, principal: string, protected: bool}> $acl
+	 * @return list<array{privilege: string, principal: string, protected: bool}>
 	 */
-	public function applyShareAcl($resourceId, $acl) {
+	public function applyShareAcl(int $resourceId, array $acl): array {
 		$shares = $this->getShares($resourceId);
 		foreach ($shares as $share) {
 			$acl[] = [
diff --git a/apps/dav/lib/DAV/Sharing/IShareable.php b/apps/dav/lib/DAV/Sharing/IShareable.php
index 3833e026696..759981af078 100644
--- a/apps/dav/lib/DAV/Sharing/IShareable.php
+++ b/apps/dav/lib/DAV/Sharing/IShareable.php
@@ -40,16 +40,14 @@ interface IShareable extends INode {
 	 * Every element in the add array has the following properties:
 	 *   * href - A url. Usually a mailto: address
 	 *   * commonName - Usually a first and last name, or false
-	 *   * summary - A description of the share, can also be false
 	 *   * readOnly - A boolean value
 	 *
 	 * Every element in the remove array is just the address string.
 	 *
-	 * @param array $add
-	 * @param array $remove
-	 * @return void
+	 * @param list<array{href: string, commonName: string, readOnly: bool}> $add
+	 * @param list<string> $remove
 	 */
-	public function updateShares(array $add, array $remove);
+	public function updateShares(array $add, array $remove): void;
 
 	/**
 	 * Returns the list of people whom this resource is shared with.
@@ -59,19 +57,15 @@ interface IShareable extends INode {
 	 *   * commonName - Optional, for example a first + last name
 	 *   * status - See the Sabre\CalDAV\SharingPlugin::STATUS_ constants.
 	 *   * readOnly - boolean
-	 *   * summary - Optional, a description for the share
 	 *
-	 * @return array
+	 * @return list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}>
 	 */
-	public function getShares();
+	public function getShares(): array;
 
-	/**
-	 * @return int
-	 */
-	public function getResourceId();
+	public function getResourceId(): int;
 
 	/**
-	 * @return string
+	 * @return ?string
 	 */
 	public function getOwner();
 }
diff --git a/apps/dav/lib/DAV/Sharing/Xml/Invite.php b/apps/dav/lib/DAV/Sharing/Xml/Invite.php
index 161a8dd0ebf..e6219f2bbfe 100644
--- a/apps/dav/lib/DAV/Sharing/Xml/Invite.php
+++ b/apps/dav/lib/DAV/Sharing/Xml/Invite.php
@@ -100,7 +100,7 @@ class Invite implements XmlSerializable {
 	}
 
 	/**
-	 * The xmlSerialize metod is called during xml writing.
+	 * The xmlSerialize method is called during xml writing.
 	 *
 	 * Use the $writer argument to write its own xml serialization.
 	 *
diff --git a/apps/dav/lib/DAV/SystemPrincipalBackend.php b/apps/dav/lib/DAV/SystemPrincipalBackend.php
index e5b9a20037f..07431feb6dd 100644
--- a/apps/dav/lib/DAV/SystemPrincipalBackend.php
+++ b/apps/dav/lib/DAV/SystemPrincipalBackend.php
@@ -87,7 +87,7 @@ class SystemPrincipalBackend extends AbstractBackend {
 	}
 
 	/**
-	 * Updates one ore more webdav properties on a principal.
+	 * Updates one or more webdav properties on a principal.
 	 *
 	 * The list of mutations is stored in a Sabre\DAV\PropPatch object.
 	 * To do the actual updates, you must tell this object which properties
diff --git a/apps/dav/lib/DAV/ViewOnlyPlugin.php b/apps/dav/lib/DAV/ViewOnlyPlugin.php
new file mode 100644
index 00000000000..1504969b5b4
--- /dev/null
+++ b/apps/dav/lib/DAV/ViewOnlyPlugin.php
@@ -0,0 +1,108 @@
+<?php
+/**
+ * @author Piotr Mrowczynski piotr@owncloud.com
+ *
+ * @copyright Copyright (c) 2019, ownCloud GmbH
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\DAV\DAV;
+
+use OCA\DAV\Connector\Sabre\Exception\Forbidden;
+use OCA\DAV\Connector\Sabre\File as DavFile;
+use OCA\DAV\Meta\MetaFile;
+use OCP\Files\FileInfo;
+use OCP\Files\NotFoundException;
+use Psr\Log\LoggerInterface;
+use Sabre\DAV\Server;
+use Sabre\DAV\ServerPlugin;
+use Sabre\HTTP\RequestInterface;
+use Sabre\DAV\Exception\NotFound;
+
+/**
+ * Sabre plugin for restricting file share receiver download:
+ */
+class ViewOnlyPlugin extends ServerPlugin {
+
+	private ?Server $server = null;
+	private LoggerInterface $logger;
+
+	public function __construct(LoggerInterface $logger) {
+		$this->logger = $logger;
+	}
+
+	/**
+	 * This initializes the plugin.
+	 *
+	 * This function is called by Sabre\DAV\Server, after
+	 * addPlugin is called.
+	 *
+	 * This method should set up the required event subscriptions.
+	 */
+	public function initialize(Server $server): void {
+		$this->server = $server;
+		//priority 90 to make sure the plugin is called before
+		//Sabre\DAV\CorePlugin::httpGet
+		$this->server->on('method:GET', [$this, 'checkViewOnly'], 90);
+	}
+
+	/**
+	 * Disallow download via DAV Api in case file being received share
+	 * and having special permission
+	 *
+	 * @throws Forbidden
+	 * @throws NotFoundException
+	 */
+	public function checkViewOnly(RequestInterface $request): bool {
+		$path = $request->getPath();
+
+		try {
+			assert($this->server !== null);
+			$davNode = $this->server->tree->getNodeForPath($path);
+			if (!($davNode instanceof DavFile)) {
+				return true;
+			}
+			// Restrict view-only to nodes which are shared
+			$node = $davNode->getNode();
+
+			$storage = $node->getStorage();
+
+			if (!$storage->instanceOfStorage(\OCA\Files_Sharing\SharedStorage::class)) {
+				return true;
+			}
+			// Extract extra permissions
+			/** @var \OCA\Files_Sharing\SharedStorage $storage */
+			$share = $storage->getShare();
+
+			$attributes = $share->getAttributes();
+			if ($attributes === null) {
+				return true;
+			}
+
+			// Check if read-only and on whether permission can download is both set and disabled.
+			$canDownload = $attributes->getAttribute('permissions', 'download');
+			if ($canDownload !== null && !$canDownload) {
+				throw new Forbidden('Access to this resource has been denied because it is in view-only mode.');
+			}
+		} catch (NotFound $e) {
+			$this->logger->warning($e->getMessage(), [
+				'exception' => $e,
+			]);
+		}
+
+		return true;
+	}
+}
diff --git a/apps/dav/lib/Direct/DirectHome.php b/apps/dav/lib/Direct/DirectHome.php
index a385cd8f39d..5453a61ed46 100644
--- a/apps/dav/lib/Direct/DirectHome.php
+++ b/apps/dav/lib/Direct/DirectHome.php
@@ -91,7 +91,7 @@ class DirectHome implements ICollection {
 
 			return new DirectFile($direct, $this->rootFolder, $this->eventDispatcher);
 		} catch (DoesNotExistException $e) {
-			// Since the token space is so huge only throttle on non exsisting token
+			// Since the token space is so huge only throttle on non-existing token
 			$this->throttler->registerAttempt('directlink', $this->request->getRemoteAddress());
 			$this->throttler->sleepDelay($this->request->getRemoteAddress(), 'directlink');
 
diff --git a/apps/dav/lib/Events/CalendarObjectMovedEvent.php b/apps/dav/lib/Events/CalendarObjectMovedEvent.php
new file mode 100644
index 00000000000..0143dad9a96
--- /dev/null
+++ b/apps/dav/lib/Events/CalendarObjectMovedEvent.php
@@ -0,0 +1,120 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\DAV\Events;
+
+use OCP\EventDispatcher\Event;
+
+/**
+ * Class CalendarObjectMovedEvent
+ *
+ * @package OCA\DAV\Events
+ * @since 25.0.0
+ */
+class CalendarObjectMovedEvent extends Event {
+	private int $sourceCalendarId;
+	private array $sourceCalendarData;
+	private int $targetCalendarId;
+	private array $targetCalendarData;
+	private array $sourceShares;
+	private array $targetShares;
+	private array $objectData;
+
+	/**
+	 * @since 25.0.0
+	 */
+	public function __construct(int $sourceCalendarId,
+								array $sourceCalendarData,
+								int $targetCalendarId,
+								array $targetCalendarData,
+								array $sourceShares,
+								array $targetShares,
+								array $objectData) {
+		parent::__construct();
+		$this->sourceCalendarId = $sourceCalendarId;
+		$this->sourceCalendarData = $sourceCalendarData;
+		$this->targetCalendarId = $targetCalendarId;
+		$this->targetCalendarData = $targetCalendarData;
+		$this->sourceShares = $sourceShares;
+		$this->targetShares = $targetShares;
+		$this->objectData = $objectData;
+	}
+
+	/**
+	 * @return int
+	 * @since 25.0.0
+	 */
+	public function getSourceCalendarId(): int {
+		return $this->sourceCalendarId;
+	}
+
+	/**
+	 * @return array
+	 * @since 25.0.0
+	 */
+	public function getSourceCalendarData(): array {
+		return $this->sourceCalendarData;
+	}
+
+	/**
+	 * @return int
+	 * @since 25.0.0
+	 */
+	public function getTargetCalendarId(): int {
+		return $this->targetCalendarId;
+	}
+
+	/**
+	 * @return array
+	 * @since 25.0.0
+	 */
+	public function getTargetCalendarData(): array {
+		return $this->targetCalendarData;
+	}
+
+	/**
+	 * @return array
+	 * @since 25.0.0
+	 */
+	public function getSourceShares(): array {
+		return $this->sourceShares;
+	}
+
+	/**
+	 * @return array
+	 * @since 25.0.0
+	 */
+	public function getTargetShares(): array {
+		return $this->targetShares;
+	}
+
+	/**
+	 * @return array
+	 * @since 25.0.0
+	 */
+	public function getObjectData(): array {
+		return $this->objectData;
+	}
+}
diff --git a/apps/dav/lib/Events/CalendarPublishedEvent.php b/apps/dav/lib/Events/CalendarPublishedEvent.php
index 7b3b95f2f77..a95e9f294c1 100644
--- a/apps/dav/lib/Events/CalendarPublishedEvent.php
+++ b/apps/dav/lib/Events/CalendarPublishedEvent.php
@@ -6,6 +6,7 @@ declare(strict_types=1);
  * @copyright Copyright (c) 2020, Georg Ehrke
  *
  * @author Georg Ehrke <oc.list@georgehrke.com>
+ * @author Thomas Citharel <nextcloud@tcit.fr>
  *
  * @license GNU AGPL version 3 or any later version
  *
@@ -34,15 +35,9 @@ use OCP\EventDispatcher\Event;
  * @since 20.0.0
  */
 class CalendarPublishedEvent extends Event {
-
-	/** @var int */
-	private $calendarId;
-
-	/** @var array */
-	private $calendarData;
-
-	/** @var string */
-	private $publicUri;
+	private int $calendarId;
+	private array $calendarData;
+	private string $publicUri;
 
 	/**
 	 * CalendarPublishedEvent constructor.
diff --git a/apps/dav/lib/Events/CalendarShareUpdatedEvent.php b/apps/dav/lib/Events/CalendarShareUpdatedEvent.php
index a9011bc0273..d5a568d149b 100644
--- a/apps/dav/lib/Events/CalendarShareUpdatedEvent.php
+++ b/apps/dav/lib/Events/CalendarShareUpdatedEvent.php
@@ -26,6 +26,8 @@ declare(strict_types=1);
 namespace OCA\DAV\Events;
 
 use OCP\EventDispatcher\Event;
+use Sabre\CalDAV\Xml\Property\ScheduleCalendarTransp;
+use Sabre\CalDAV\Xml\Property\SupportedCalendarComponentSet;
 
 /**
  * Class CalendarShareUpdatedEvent
@@ -34,30 +36,28 @@ use OCP\EventDispatcher\Event;
  * @since 20.0.0
  */
 class CalendarShareUpdatedEvent extends Event {
+	private int $calendarId;
 
-	/** @var int */
-	private $calendarId;
+	/** @var array{id: int, uri: string, '{http://calendarserver.org/ns/}getctag': string, '{http://sabredav.org/ns}sync-token': int, '{urn:ietf:params:xml:ns:caldav}supported-calendar-component-set': SupportedCalendarComponentSet, '{urn:ietf:params:xml:ns:caldav}schedule-calendar-transp': ScheduleCalendarTransp } */
+	private array $calendarData;
 
-	/** @var array */
-	private $calendarData;
+	/** @var list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}> */
+	private array $oldShares;
 
-	/** @var array */
-	private $oldShares;
+	/** @var list<array{href: string, commonName: string, readOnly: bool}> */
+	private array $added;
 
-	/** @var array */
-	private $added;
-
-	/** @var array */
-	private $removed;
+	/** @var list<string> */
+	private array $removed;
 
 	/**
 	 * CalendarShareUpdatedEvent constructor.
 	 *
 	 * @param int $calendarId
-	 * @param array $calendarData
-	 * @param array $oldShares
-	 * @param array $added
-	 * @param array $removed
+	 * @param array{id: int, uri: string, '{http://calendarserver.org/ns/}getctag': string, '{http://sabredav.org/ns}sync-token': int, '{urn:ietf:params:xml:ns:caldav}supported-calendar-component-set': SupportedCalendarComponentSet, '{urn:ietf:params:xml:ns:caldav}schedule-calendar-transp': ScheduleCalendarTransp } $calendarData
+	 * @param list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}> $oldShares
+	 * @param list<array{href: string, commonName: string, readOnly: bool}> $added
+	 * @param list<string> $removed
 	 * @since 20.0.0
 	 */
 	public function __construct(int $calendarId,
@@ -74,7 +74,6 @@ class CalendarShareUpdatedEvent extends Event {
 	}
 
 	/**
-	 * @return int
 	 * @since 20.0.0
 	 */
 	public function getCalendarId(): int {
@@ -82,7 +81,7 @@ class CalendarShareUpdatedEvent extends Event {
 	}
 
 	/**
-	 * @return array
+	 * @return array{id: int, uri: string, '{http://calendarserver.org/ns/}getctag': string, '{http://sabredav.org/ns}sync-token': int, '{urn:ietf:params:xml:ns:caldav}supported-calendar-component-set': SupportedCalendarComponentSet, '{urn:ietf:params:xml:ns:caldav}schedule-calendar-transp': ScheduleCalendarTransp }
 	 * @since 20.0.0
 	 */
 	public function getCalendarData(): array {
@@ -90,7 +89,7 @@ class CalendarShareUpdatedEvent extends Event {
 	}
 
 	/**
-	 * @return array
+	 * @return list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}>
 	 * @since 20.0.0
 	 */
 	public function getOldShares(): array {
@@ -98,7 +97,7 @@ class CalendarShareUpdatedEvent extends Event {
 	}
 
 	/**
-	 * @return array
+	 * @return list<array{href: string, commonName: string, readOnly: bool}>
 	 * @since 20.0.0
 	 */
 	public function getAdded(): array {
@@ -106,7 +105,7 @@ class CalendarShareUpdatedEvent extends Event {
 	}
 
 	/**
-	 * @return array
+	 * @return list<string>
 	 * @since 20.0.0
 	 */
 	public function getRemoved(): array {
diff --git a/apps/dav/lib/Events/CalendarUnpublishedEvent.php b/apps/dav/lib/Events/CalendarUnpublishedEvent.php
index 0cea53c6f0d..b2536fc7aef 100644
--- a/apps/dav/lib/Events/CalendarUnpublishedEvent.php
+++ b/apps/dav/lib/Events/CalendarUnpublishedEvent.php
@@ -6,6 +6,7 @@ declare(strict_types=1);
  * @copyright Copyright (c) 2020, Georg Ehrke
  *
  * @author Georg Ehrke <oc.list@georgehrke.com>
+ * @author Thomas Citharel <nextcloud@tcit.fr>
  *
  * @license GNU AGPL version 3 or any later version
  *
@@ -34,12 +35,8 @@ use OCP\EventDispatcher\Event;
  * @since 20.0.0
  */
 class CalendarUnpublishedEvent extends Event {
-
-	/** @var int */
-	private $calendarId;
-
-	/** @var array */
-	private $calendarData;
+	private int $calendarId;
+	private array $calendarData;
 
 	/**
 	 * CalendarUnpublishedEvent constructor.
diff --git a/apps/dav/lib/Exception/ServerMaintenanceMode.php b/apps/dav/lib/Exception/ServerMaintenanceMode.php
new file mode 100644
index 00000000000..9dad9f2d4d1
--- /dev/null
+++ b/apps/dav/lib/Exception/ServerMaintenanceMode.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2022 Joas Schilling <coding@schilljs.com>
+ *
+ * @author Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\DAV\Exception;
+
+use Sabre\DAV\Exception\ServiceUnavailable;
+
+class ServerMaintenanceMode extends ServiceUnavailable {
+
+}
diff --git a/apps/dav/lib/Listener/ActivityUpdaterListener.php b/apps/dav/lib/Listener/ActivityUpdaterListener.php
index 371912ff035..ea3ec49c14d 100644
--- a/apps/dav/lib/Listener/ActivityUpdaterListener.php
+++ b/apps/dav/lib/Listener/ActivityUpdaterListener.php
@@ -32,6 +32,7 @@ use OCA\DAV\Events\CalendarDeletedEvent;
 use OCA\DAV\Events\CalendarMovedToTrashEvent;
 use OCA\DAV\Events\CalendarObjectCreatedEvent;
 use OCA\DAV\Events\CalendarObjectDeletedEvent;
+use OCA\DAV\Events\CalendarObjectMovedEvent;
 use OCA\DAV\Events\CalendarObjectMovedToTrashEvent;
 use OCA\DAV\Events\CalendarObjectRestoredEvent;
 use OCA\DAV\Events\CalendarObjectUpdatedEvent;
@@ -173,7 +174,26 @@ class ActivityUpdaterListener implements IEventListener {
 				);
 
 				$this->logger->debug(
-					sprintf('Activity generated for deleted calendar object %d', $event->getCalendarId())
+					sprintf('Activity generated for updated calendar object in calendar %d', $event->getCalendarId())
+				);
+			} catch (Throwable $e) {
+				// Any error with activities shouldn't abort the calendar deletion, so we just log it
+				$this->logger->error('Error generating activity for a deleted calendar object: ' . $e->getMessage(), [
+					'exception' => $e,
+				]);
+			}
+		} elseif ($event instanceof CalendarObjectMovedEvent) {
+			try {
+				$this->activityBackend->onMovedCalendarObject(
+					$event->getSourceCalendarData(),
+					$event->getTargetCalendarData(),
+					$event->getSourceShares(),
+					$event->getTargetShares(),
+					$event->getObjectData()
+				);
+
+				$this->logger->debug(
+					sprintf('Activity generated for moved calendar object from calendar %d to calendar %d', $event->getSourceCalendarId(), $event->getTargetCalendarId())
 				);
 			} catch (Throwable $e) {
 				// Any error with activities shouldn't abort the calendar deletion, so we just log it
diff --git a/apps/dav/lib/Listener/BirthdayListener.php b/apps/dav/lib/Listener/BirthdayListener.php
new file mode 100644
index 00000000000..43ad782fa9e
--- /dev/null
+++ b/apps/dav/lib/Listener/BirthdayListener.php
@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2022 Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @author Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\DAV\Listener;
+
+use OCA\DAV\CalDAV\BirthdayService;
+use OCA\DAV\Events\CardCreatedEvent;
+use OCA\DAV\Events\CardDeletedEvent;
+use OCA\DAV\Events\CardUpdatedEvent;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+
+class BirthdayListener implements IEventListener {
+	private BirthdayService $birthdayService;
+
+	public function __construct(BirthdayService $birthdayService) {
+		$this->birthdayService = $birthdayService;
+	}
+
+	public function handle(Event $event): void {
+		if ($event instanceof CardCreatedEvent || $event instanceof CardUpdatedEvent) {
+			$cardData = $event->getCardData();
+
+			$this->birthdayService->onCardChanged($event->getAddressBookId(), $cardData['uri'], $cardData['carddata']);
+		}
+
+		if ($event instanceof CardDeletedEvent) {
+			$cardData = $event->getCardData();
+			$this->birthdayService->onCardDeleted($event->getAddressBookId(), $cardData['uri']);
+		}
+	}
+}
diff --git a/apps/dav/lib/Listener/CalendarPublicationListener.php b/apps/dav/lib/Listener/CalendarPublicationListener.php
new file mode 100644
index 00000000000..1453694d6fb
--- /dev/null
+++ b/apps/dav/lib/Listener/CalendarPublicationListener.php
@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2022 Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @author Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\DAV\Listener;
+
+use OCA\DAV\CalDAV\Activity\Backend;
+use OCA\DAV\Events\CalendarPublishedEvent;
+use OCA\DAV\Events\CalendarUnpublishedEvent;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use Psr\Log\LoggerInterface;
+
+class CalendarPublicationListener implements IEventListener {
+	private Backend $activityBackend;
+	private LoggerInterface $logger;
+
+	public function __construct(Backend $activityBackend,
+								LoggerInterface $logger) {
+		$this->activityBackend = $activityBackend;
+		$this->logger = $logger;
+	}
+
+	/**
+	 * In case the user has set their default calendar to the deleted one
+	 */
+	public function handle(Event $event): void {
+		if ($event instanceof CalendarPublishedEvent) {
+			$this->logger->debug('Creating activity for Calendar being published');
+
+			$this->activityBackend->onCalendarPublication(
+				$event->getCalendarData(),
+				true
+			);
+		} elseif ($event instanceof CalendarUnpublishedEvent) {
+			$this->logger->debug('Creating activity for Calendar being unpublished');
+
+			$this->activityBackend->onCalendarPublication(
+				$event->getCalendarData(),
+				false
+			);
+		}
+	}
+}
diff --git a/apps/dav/lib/Listener/CalendarShareUpdateListener.php b/apps/dav/lib/Listener/CalendarShareUpdateListener.php
new file mode 100644
index 00000000000..88865759162
--- /dev/null
+++ b/apps/dav/lib/Listener/CalendarShareUpdateListener.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2022 Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @author Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\DAV\Listener;
+
+use OCA\DAV\CalDAV\Activity\Backend;
+use OCA\DAV\Events\CalendarShareUpdatedEvent;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use Psr\Log\LoggerInterface;
+
+class CalendarShareUpdateListener implements IEventListener {
+	private Backend $activityBackend;
+	private LoggerInterface $logger;
+
+	public function __construct(Backend $activityBackend,
+								LoggerInterface $logger) {
+		$this->activityBackend = $activityBackend;
+		$this->logger = $logger;
+	}
+
+	/**
+	 * In case the user has set their default calendar to the deleted one
+	 */
+	public function handle(Event $event): void {
+		if (!($event instanceof CalendarShareUpdatedEvent)) {
+			// Not what we subscribed to
+			return;
+		}
+
+		$this->logger->debug("Creating activity for Calendar having it's shares updated");
+
+		$this->activityBackend->onCalendarUpdateShares(
+			$event->getCalendarData(),
+			$event->getOldShares(),
+			$event->getAdded(),
+			$event->getRemoved()
+		);
+	}
+}
diff --git a/apps/dav/lib/Listener/ClearPhotoCacheListener.php b/apps/dav/lib/Listener/ClearPhotoCacheListener.php
new file mode 100644
index 00000000000..ed02770e35d
--- /dev/null
+++ b/apps/dav/lib/Listener/ClearPhotoCacheListener.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2022 Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @author Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\DAV\Listener;
+
+use OCA\DAV\CardDAV\PhotoCache;
+use OCA\DAV\Events\CardDeletedEvent;
+use OCA\DAV\Events\CardUpdatedEvent;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+
+class ClearPhotoCacheListener implements IEventListener {
+	private PhotoCache $photoCache;
+
+	public function __construct(PhotoCache $photoCache) {
+		$this->photoCache = $photoCache;
+	}
+
+	public function handle(Event $event): void {
+		if ($event instanceof CardUpdatedEvent || $event instanceof CardDeletedEvent) {
+			$cardData = $event->getCardData();
+
+			$this->photoCache->delete($event->getAddressBookId(), $cardData['uri']);
+		}
+	}
+}
diff --git a/apps/dav/lib/Listener/SubscriptionListener.php b/apps/dav/lib/Listener/SubscriptionListener.php
new file mode 100644
index 00000000000..36db234aa05
--- /dev/null
+++ b/apps/dav/lib/Listener/SubscriptionListener.php
@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2022 Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @author Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\DAV\Listener;
+
+use OCA\DAV\BackgroundJob\RefreshWebcalJob;
+use OCA\DAV\CalDAV\Reminder\Backend as ReminderBackend;
+use OCA\DAV\CalDAV\WebcalCaching\RefreshWebcalService;
+use OCA\DAV\Events\SubscriptionCreatedEvent;
+use OCA\DAV\Events\SubscriptionDeletedEvent;
+use OCP\BackgroundJob\IJobList;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use Psr\Log\LoggerInterface;
+
+class SubscriptionListener implements IEventListener {
+	private IJobList $jobList;
+	private RefreshWebcalService $refreshWebcalService;
+	private ReminderBackend $reminderBackend;
+	private LoggerInterface $logger;
+
+	public function __construct(IJobList $jobList, RefreshWebcalService $refreshWebcalService, ReminderBackend $reminderBackend,
+								LoggerInterface $logger) {
+		$this->jobList = $jobList;
+		$this->refreshWebcalService = $refreshWebcalService;
+		$this->reminderBackend = $reminderBackend;
+		$this->logger = $logger;
+	}
+
+	/**
+	 * In case the user has set their default calendar to the deleted one
+	 */
+	public function handle(Event $event): void {
+		if ($event instanceof SubscriptionCreatedEvent) {
+			$subscriptionId = $event->getSubscriptionId();
+			$subscriptionData = $event->getSubscriptionData();
+
+			$this->logger->debug('Refreshing webcal data for subscription ' . $subscriptionId);
+			$this->refreshWebcalService->refreshSubscription(
+				(string)$subscriptionData['principaluri'],
+				(string)$subscriptionData['uri']
+			);
+
+			$this->logger->debug('Scheduling webcal data refreshment for subscription ' . $subscriptionId);
+			$this->jobList->add(RefreshWebcalJob::class, [
+				'principaluri' => $subscriptionData['principaluri'],
+				'uri' => $subscriptionData['uri']
+			]);
+		} elseif ($event instanceof SubscriptionDeletedEvent) {
+			$subscriptionId = $event->getSubscriptionId();
+			$subscriptionData = $event->getSubscriptionData();
+
+			$this->logger->debug('Removing refresh webcal job for subscription ' . $subscriptionId);
+			$this->jobList->remove(RefreshWebcalJob::class, [
+				'principaluri' => $subscriptionData['principaluri'],
+				'uri' => $subscriptionData['uri']
+			]);
+
+			$this->logger->debug('Cleaning all reminders for subscription ' . $subscriptionId);
+			$this->reminderBackend->cleanRemindersForCalendar($subscriptionId);
+		}
+	}
+}
diff --git a/apps/dav/lib/Listener/TrustedServerRemovedListener.php b/apps/dav/lib/Listener/TrustedServerRemovedListener.php
new file mode 100644
index 00000000000..29ff050983b
--- /dev/null
+++ b/apps/dav/lib/Listener/TrustedServerRemovedListener.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2022 Carl Schwan <carl@carlschwan.eu>
+ *
+ * @author Carl Schwan <carl@carlschwan.eu>
+ *
+ * @license AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\DAV\Listener;
+
+use OCA\DAV\CardDAV\CardDavBackend;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use OCP\Federation\Events\TrustedServerRemovedEvent;
+
+class TrustedServerRemovedListener implements IEventListener {
+	private CardDavBackend $cardDavBackend;
+
+	public function __construct(CardDavBackend $cardDavBackend) {
+		$this->cardDavBackend = $cardDavBackend;
+	}
+
+	public function handle(Event $event): void {
+		if (!$event instanceof TrustedServerRemovedEvent) {
+			return;
+		}
+		$addressBookUri = $event->getUrlHash();
+		$addressBook = $this->cardDavBackend->getAddressBooksByUri('principals/system/system', $addressBookUri);
+		if (!is_null($addressBook)) {
+			$this->cardDavBackend->deleteAddressBook($addressBook['id']);
+		}
+	}
+}
diff --git a/apps/dav/lib/Listener/UserPreferenceListener.php b/apps/dav/lib/Listener/UserPreferenceListener.php
new file mode 100644
index 00000000000..947f6d3fd01
--- /dev/null
+++ b/apps/dav/lib/Listener/UserPreferenceListener.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2022 Joas Schilling <coding@schilljs.com>
+ *
+ * @author Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\DAV\Listener;
+
+use OCA\DAV\BackgroundJob\UserStatusAutomation;
+use OCP\BackgroundJob\IJobList;
+use OCP\Config\BeforePreferenceDeletedEvent;
+use OCP\Config\BeforePreferenceSetEvent;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+
+class UserPreferenceListener implements IEventListener {
+
+	protected IJobList $jobList;
+
+	public function __construct(IJobList $jobList) {
+		$this->jobList = $jobList;
+	}
+
+	public function handle(Event $event): void {
+		if ($event instanceof BeforePreferenceSetEvent) {
+			if ($event->getAppId() === 'dav' && $event->getConfigKey() === 'user_status_automation' && $event->getConfigValue() === 'yes') {
+				$event->setValid(true);
+
+				// Not the cleanest way, but we just add the job in the before event.
+				// If something ever turns wrong the first execution will remove the job again.
+				// We also first delete the current job, so the next run time is reset.
+				$this->jobList->remove(UserStatusAutomation::class, ['userId' => $event->getUserId()]);
+				$this->jobList->add(UserStatusAutomation::class, ['userId' => $event->getUserId()]);
+			}
+		} elseif ($event instanceof BeforePreferenceDeletedEvent) {
+			if ($event->getAppId() === 'dav' && $event->getConfigKey() === 'user_status_automation') {
+				$event->setValid(true);
+			}
+		}
+	}
+}
diff --git a/apps/dav/lib/Migration/RemoveObjectProperties.php b/apps/dav/lib/Migration/RemoveObjectProperties.php
new file mode 100644
index 00000000000..c72dfbebfea
--- /dev/null
+++ b/apps/dav/lib/Migration/RemoveObjectProperties.php
@@ -0,0 +1,65 @@
+<?php
+/**
+ * @copyright Copyright (c) 2021, Thomas Citharel <nextcloud@tcit.fr>.
+ *
+ * @author Thomas Citharel <nextcloud@tcit.fr>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program. If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+namespace OCA\DAV\Migration;
+
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\IDBConnection;
+use OCP\Migration\IOutput;
+use OCP\Migration\IRepairStep;
+
+class RemoveObjectProperties implements IRepairStep {
+	private const RESOURCE_TYPE_PROPERTY = '{DAV:}resourcetype';
+	private const ME_CARD_PROPERTY = '{http://calendarserver.org/ns/}me-card';
+	private const CALENDAR_TRANSP_PROPERTY = '{urn:ietf:params:xml:ns:caldav}schedule-calendar-transp';
+
+	/** @var IDBConnection */
+	private $connection;
+
+	/**
+	 * RemoveObjectProperties constructor.
+	 *
+	 * @param IDBConnection $connection
+	 */
+	public function __construct(IDBConnection $connection) {
+		$this->connection = $connection;
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function getName() {
+		return 'Remove invalid object properties';
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function run(IOutput $output) {
+		$query = $this->connection->getQueryBuilder();
+		$updated = $query->delete('properties')
+			->where($query->expr()->in('propertyname', $query->createNamedParameter([self::RESOURCE_TYPE_PROPERTY, self::ME_CARD_PROPERTY, self::CALENDAR_TRANSP_PROPERTY], IQueryBuilder::PARAM_STR_ARRAY)))
+			->andWhere($query->expr()->eq('propertyvalue', $query->createNamedParameter('Object')))
+			->executeStatement();
+
+		$output->info("$updated invalid object properties removed.");
+	}
+}
diff --git a/apps/dav/lib/Migration/Version1024Date20211221144219.php b/apps/dav/lib/Migration/Version1024Date20211221144219.php
new file mode 100644
index 00000000000..b93f8ac801e
--- /dev/null
+++ b/apps/dav/lib/Migration/Version1024Date20211221144219.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\DAV\Migration;
+
+use Closure;
+use Doctrine\DBAL\Schema\SchemaException;
+use OCA\DAV\DAV\CustomPropertiesBackend;
+use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+/**
+ * Auto-generated migration step: Please modify to your needs!
+ */
+class Version1024Date20211221144219 extends SimpleMigrationStep {
+
+	/**
+	 * @param IOutput $output
+	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 */
+	public function preSchemaChange(IOutput $output, Closure $schemaClosure, array $options): void {
+	}
+
+	/**
+	 * @param IOutput $output
+	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 * @throws SchemaException
+	 */
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+		$propertiesTable = $schema->getTable('properties');
+
+		if ($propertiesTable->hasColumn('valuetype')) {
+			return null;
+		}
+		$propertiesTable->addColumn('valuetype', Types::SMALLINT, [
+			'notnull' => false,
+			'default' => CustomPropertiesBackend::PROPERTY_TYPE_STRING
+		]);
+
+		return $schema;
+	}
+
+	/**
+	 * @param IOutput $output
+	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 */
+	public function postSchemaChange(IOutput $output, Closure $schemaClosure, array $options): void {
+	}
+}
diff --git a/apps/dav/lib/RootCollection.php b/apps/dav/lib/RootCollection.php
index 8a11a676609..29ab65d46a9 100644
--- a/apps/dav/lib/RootCollection.php
+++ b/apps/dav/lib/RootCollection.php
@@ -7,6 +7,7 @@
  * @author Georg Ehrke <oc.list@georgehrke.com>
  * @author Joas Schilling <coding@schilljs.com>
  * @author Roeland Jago Douma <roeland@famdouma.nl>
+ * @author Thomas Citharel <nextcloud@tcit.fr>
  * @author Thomas Müller <thomas.mueller@tmit.eu>
  * @author Vincent Petry <vincent@nextcloud.com>
  *
@@ -43,6 +44,7 @@ use OCA\DAV\DAV\GroupPrincipalBackend;
 use OCA\DAV\DAV\SystemPrincipalBackend;
 use OCA\DAV\Provisioning\Apple\AppleProvisioningNode;
 use OCA\DAV\Upload\CleanupService;
+use OCP\Accounts\IAccountManager;
 use OCP\App\IAppManager;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\EventDispatcher\IEventDispatcher;
@@ -61,13 +63,13 @@ class RootCollection extends SimpleCollection {
 		$shareManager = \OC::$server->getShareManager();
 		$db = \OC::$server->getDatabaseConnection();
 		$dispatcher = \OC::$server->get(IEventDispatcher::class);
-		$legacyDispatcher = \OC::$server->getEventDispatcher();
 		$config = \OC::$server->get(IConfig::class);
 		$proxyMapper = \OC::$server->query(ProxyMapper::class);
 
 		$userPrincipalBackend = new Principal(
 			$userManager,
 			$groupManager,
+			\OC::$server->get(IAccountManager::class),
 			$shareManager,
 			\OC::$server->getUserSession(),
 			\OC::$server->getAppManager(),
@@ -105,7 +107,6 @@ class RootCollection extends SimpleCollection {
 			$random,
 			$logger,
 			$dispatcher,
-			$legacyDispatcher,
 			$config
 		);
 		$userCalendarRoot = new CalendarRoot($userPrincipalBackend, $caldavBackend, 'principals/users', $logger);
@@ -140,11 +141,11 @@ class RootCollection extends SimpleCollection {
 		);
 
 		$pluginManager = new PluginManager(\OC::$server, \OC::$server->query(IAppManager::class));
-		$usersCardDavBackend = new CardDavBackend($db, $userPrincipalBackend, $userManager, $groupManager, $dispatcher, $legacyDispatcher);
+		$usersCardDavBackend = new CardDavBackend($db, $userPrincipalBackend, $userManager, $groupManager, $dispatcher);
 		$usersAddressBookRoot = new AddressBookRoot($userPrincipalBackend, $usersCardDavBackend, $pluginManager, 'principals/users');
 		$usersAddressBookRoot->disableListing = $disableListing;
 
-		$systemCardDavBackend = new CardDavBackend($db, $userPrincipalBackend, $userManager, $groupManager, $dispatcher, $legacyDispatcher);
+		$systemCardDavBackend = new CardDavBackend($db, $userPrincipalBackend, $userManager, $groupManager, $dispatcher);
 		$systemAddressBookRoot = new AddressBookRoot(new SystemPrincipalBackend(), $systemCardDavBackend, $pluginManager, 'principals/system');
 		$systemAddressBookRoot->disableListing = $disableListing;
 
diff --git a/apps/dav/lib/Server.php b/apps/dav/lib/Server.php
index 5b532465aba..2cfcb3f5393 100644
--- a/apps/dav/lib/Server.php
+++ b/apps/dav/lib/Server.php
@@ -62,6 +62,7 @@ use OCA\DAV\Connector\Sabre\SharesPlugin;
 use OCA\DAV\Connector\Sabre\TagsPlugin;
 use OCA\DAV\DAV\CustomPropertiesBackend;
 use OCA\DAV\DAV\PublicAuth;
+use OCA\DAV\DAV\ViewOnlyPlugin;
 use OCA\DAV\Events\SabrePluginAuthInitEvent;
 use OCA\DAV\Files\BrowserErrorPagePlugin;
 use OCA\DAV\Files\LazySearchBackend;
@@ -229,6 +230,11 @@ class Server {
 			$this->server->addPlugin(new FakeLockerPlugin());
 		}
 
+		// Allow view-only plugin for webdav requests
+		$this->server->addPlugin(new ViewOnlyPlugin(
+			$logger
+		));
+
 		if (BrowserErrorPagePlugin::isBrowserRequest($request)) {
 			$this->server->addPlugin(new BrowserErrorPagePlugin());
 		}
diff --git a/apps/dav/lib/Settings/AvailabilitySettings.php b/apps/dav/lib/Settings/AvailabilitySettings.php
index 9a163e21edb..d2b75ba4866 100644
--- a/apps/dav/lib/Settings/AvailabilitySettings.php
+++ b/apps/dav/lib/Settings/AvailabilitySettings.php
@@ -27,10 +27,34 @@ namespace OCA\DAV\Settings;
 
 use OCA\DAV\AppInfo\Application;
 use OCP\AppFramework\Http\TemplateResponse;
+use OCP\AppFramework\Services\IInitialState;
+use OCP\IConfig;
 use OCP\Settings\ISettings;
 
 class AvailabilitySettings implements ISettings {
+	protected IConfig $config;
+	protected IInitialState $initialState;
+	protected ?string $userId;
+
+	public function __construct(IConfig $config,
+								IInitialState $initialState,
+								?string $userId) {
+		$this->config = $config;
+		$this->initialState = $initialState;
+		$this->userId = $userId;
+	}
+
 	public function getForm(): TemplateResponse {
+		$this->initialState->provideInitialState(
+			'user_status_automation',
+			$this->config->getUserValue(
+				$this->userId,
+				'dav',
+				'user_status_automation',
+				'no'
+			)
+		);
+
 		return new TemplateResponse(Application::APP_ID, 'settings-personal-availability');
 	}
 
diff --git a/apps/dav/lib/UserMigration/ContactsMigrator.php b/apps/dav/lib/UserMigration/ContactsMigrator.php
index ae1a61ce4f4..d2ba82eb2e5 100644
--- a/apps/dav/lib/UserMigration/ContactsMigrator.php
+++ b/apps/dav/lib/UserMigration/ContactsMigrator.php
@@ -131,6 +131,10 @@ class ContactsMigrator implements IMigrator, ISizeEstimationMigrator {
 			}
 		}
 
+		if (count($vCards) === 0) {
+			throw new InvalidAddressBookException();
+		}
+
 		return [
 			'name' => $addressBookNode->getName(),
 			'displayName' => $addressBookInfo['{DAV:}displayname'],