diff --git a/apps/files/tests/Sharing/Source/NodeShareSourceTypeTest.php b/apps/files/tests/Sharing/Source/NodeShareSourceTypeTest.php
index 31d699361cfd0..ee1e3a5a35414 100644
--- a/apps/files/tests/Sharing/Source/NodeShareSourceTypeTest.php
+++ b/apps/files/tests/Sharing/Source/NodeShareSourceTypeTest.php
@@ -12,6 +12,7 @@
 use NCU\Sharing\ShareAccessContext;
 use NCU\Sharing\Source\ShareSource;
 use OC\Files\Filesystem;
+use OC\Sharing\SharingManager;
 use OC\User\Database;
 use OCA\Files\Sharing\Source\NodeShareSourceType;
 use OCP\EventDispatcher\IEventDispatcher;
@@ -103,14 +104,14 @@ public function testDelete(): void {
 		$this->manager->addShareSource($accessContext, $id, new ShareSource($this->sourceType::class, (string)$this->node->getId()));
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->node->delete();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$this->dbConnection->beginTransaction();
 		$share = $this->manager->getShare($accessContext, $id);
-		$this->assertGreaterThanOrEqual($before, $share->lastUpdated);
-		$this->assertLessThanOrEqual($after, $share->lastUpdated);
+		$this->assertGreaterThanOrEqual($before, SharingManager::timeToMs($share->lastUpdated));
+		$this->assertLessThanOrEqual($after, SharingManager::timeToMs($share->lastUpdated));
 		$this->assertEquals([], $share->sources);
 
 		$this->manager->deleteShare($accessContext, $id);
diff --git a/apps/files_sharing/composer/composer/autoload_classmap.php b/apps/files_sharing/composer/composer/autoload_classmap.php
index 36aa12de200aa..b9aad64edd185 100644
--- a/apps/files_sharing/composer/composer/autoload_classmap.php
+++ b/apps/files_sharing/composer/composer/autoload_classmap.php
@@ -93,6 +93,7 @@
     'OCA\\Files_Sharing\\Migration\\Version33000Date20251030081948' => $baseDir . '/../lib/Migration/Version33000Date20251030081948.php',
     'OCA\\Files_Sharing\\Migration\\Version33000Date20260306120000' => $baseDir . '/../lib/Migration/Version33000Date20260306120000.php',
     'OCA\\Files_Sharing\\Migration\\Version33000Date20260306150000' => $baseDir . '/../lib/Migration/Version33000Date20260306150000.php',
+    'OCA\\Files_Sharing\\Migration\\Version35000Date20260720121254' => $baseDir . '/../lib/Migration/Version35000Date20260720121254.php',
     'OCA\\Files_Sharing\\MountProvider' => $baseDir . '/../lib/MountProvider.php',
     'OCA\\Files_Sharing\\Notification\\Listener' => $baseDir . '/../lib/Notification/Listener.php',
     'OCA\\Files_Sharing\\Notification\\Notifier' => $baseDir . '/../lib/Notification/Notifier.php',
@@ -107,6 +108,7 @@
     'OCA\\Files_Sharing\\SharedMount' => $baseDir . '/../lib/SharedMount.php',
     'OCA\\Files_Sharing\\SharedStorage' => $baseDir . '/../lib/SharedStorage.php',
     'OCA\\Files_Sharing\\SharesReminderJob' => $baseDir . '/../lib/SharesReminderJob.php',
+    'OCA\\Files_Sharing\\Sharing\\LegacyBackend' => $baseDir . '/../lib/Sharing/LegacyBackend.php',
     'OCA\\Files_Sharing\\Updater' => $baseDir . '/../lib/Updater.php',
     'OCA\\Files_Sharing\\ViewOnly' => $baseDir . '/../lib/ViewOnly.php',
 );
diff --git a/apps/files_sharing/composer/composer/autoload_static.php b/apps/files_sharing/composer/composer/autoload_static.php
index 0550359c85807..cf671c5fa5964 100644
--- a/apps/files_sharing/composer/composer/autoload_static.php
+++ b/apps/files_sharing/composer/composer/autoload_static.php
@@ -108,6 +108,7 @@ class ComposerStaticInitFiles_Sharing
         'OCA\\Files_Sharing\\Migration\\Version33000Date20251030081948' => __DIR__ . '/..' . '/../lib/Migration/Version33000Date20251030081948.php',
         'OCA\\Files_Sharing\\Migration\\Version33000Date20260306120000' => __DIR__ . '/..' . '/../lib/Migration/Version33000Date20260306120000.php',
         'OCA\\Files_Sharing\\Migration\\Version33000Date20260306150000' => __DIR__ . '/..' . '/../lib/Migration/Version33000Date20260306150000.php',
+        'OCA\\Files_Sharing\\Migration\\Version35000Date20260720121254' => __DIR__ . '/..' . '/../lib/Migration/Version35000Date20260720121254.php',
         'OCA\\Files_Sharing\\MountProvider' => __DIR__ . '/..' . '/../lib/MountProvider.php',
         'OCA\\Files_Sharing\\Notification\\Listener' => __DIR__ . '/..' . '/../lib/Notification/Listener.php',
         'OCA\\Files_Sharing\\Notification\\Notifier' => __DIR__ . '/..' . '/../lib/Notification/Notifier.php',
@@ -122,6 +123,7 @@ class ComposerStaticInitFiles_Sharing
         'OCA\\Files_Sharing\\SharedMount' => __DIR__ . '/..' . '/../lib/SharedMount.php',
         'OCA\\Files_Sharing\\SharedStorage' => __DIR__ . '/..' . '/../lib/SharedStorage.php',
         'OCA\\Files_Sharing\\SharesReminderJob' => __DIR__ . '/..' . '/../lib/SharesReminderJob.php',
+        'OCA\\Files_Sharing\\Sharing\\LegacyBackend' => __DIR__ . '/..' . '/../lib/Sharing/LegacyBackend.php',
         'OCA\\Files_Sharing\\Updater' => __DIR__ . '/..' . '/../lib/Updater.php',
         'OCA\\Files_Sharing\\ViewOnly' => __DIR__ . '/..' . '/../lib/ViewOnly.php',
     );
diff --git a/apps/files_sharing/lib/AppInfo/Application.php b/apps/files_sharing/lib/AppInfo/Application.php
index 580a3bb163d04..c9affd3fcf759 100644
--- a/apps/files_sharing/lib/AppInfo/Application.php
+++ b/apps/files_sharing/lib/AppInfo/Application.php
@@ -8,6 +8,8 @@
 
 namespace OCA\Files_Sharing\AppInfo;
 
+use NCU\Sharing\ISharingManager;
+use NCU\Sharing\ISharingRegistry;
 use OC\Group\DisplayNameCache as GroupDisplayNameCache;
 use OC\User\DisplayNameCache;
 use OCA\Files\Event\LoadAdditionalScriptsEvent;
@@ -36,6 +38,7 @@
 use OCA\Files_Sharing\MountProvider;
 use OCA\Files_Sharing\Notification\Listener;
 use OCA\Files_Sharing\Notification\Notifier;
+use OCA\Files_Sharing\Sharing\LegacyBackend;
 use OCP\AppFramework\App;
 use OCP\AppFramework\Bootstrap\IBootContext;
 use OCP\AppFramework\Bootstrap\IBootstrap;
@@ -49,6 +52,7 @@
 use OCP\Files\Events\BeforeZipCreatedEvent;
 use OCP\Files\Events\Node\BeforeNodeReadEvent;
 use OCP\Files\Events\UserHomeSetupEvent;
+use OCP\Files\IRootFolder;
 use OCP\Group\Events\BeforeGroupDeletedEvent;
 use OCP\Group\Events\GroupChangedEvent;
 use OCP\Group\Events\GroupDeletedEvent;
@@ -58,10 +62,14 @@
 use OCP\IDBConnection;
 use OCP\IGroup;
 use OCP\Interaction\RestrictInteractionEvent;
+use OCP\L10N\IFactory;
+use OCP\Server;
 use OCP\Share\Events\BeforeShareDeletedEvent;
 use OCP\Share\Events\ShareCreatedEvent;
 use OCP\Share\Events\ShareMovedEvent;
 use OCP\Share\Events\ShareTransferredEvent;
+use OCP\Share\IManager;
+use OCP\Snowflake\ISnowflakeGenerator;
 use OCP\User\Events\UserChangedEvent;
 use OCP\User\Events\UserDeletedEvent;
 use OCP\Util;
@@ -136,6 +144,9 @@ function () use ($c) {
 		$context->registerConfigLexicon(ConfigLexicon::class);
 
 		$context->registerEventListener(RestrictInteractionEvent::class, RestrictInteractionListener::class);
+
+		$registry = Server::get(ISharingRegistry::class);
+		$registry->registerLegacyBackend(Server::get(LegacyBackend::class));
 	}
 
 	#[\Override]
diff --git a/apps/files_sharing/lib/Migration/Version35000Date20260720121254.php b/apps/files_sharing/lib/Migration/Version35000Date20260720121254.php
new file mode 100644
index 0000000000000..8bdb2bab7083b
--- /dev/null
+++ b/apps/files_sharing/lib/Migration/Version35000Date20260720121254.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Files_Sharing\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+use Override;
+
+class Version35000Date20260720121254 extends SimpleMigrationStep {
+	#[Override]
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$shareLegacyMappingTable = $schema->createTable('share_legacy_mapping');
+		$shareLegacyMappingTable->addColumn('id', Types::BIGINT);
+		$shareLegacyMappingTable->addColumn('legacy_provider', Types::STRING, ['length' => 128]);
+		$shareLegacyMappingTable->addColumn('legacy_id', Types::STRING, ['length' => 128]);
+		$shareLegacyMappingTable->setPrimaryKey(['id']);
+		$shareLegacyMappingTable->addUniqueIndex(['legacy_provider', 'legacy_id']);
+
+		return null;
+	}
+}
diff --git a/apps/files_sharing/lib/Sharing/LegacyBackend.php b/apps/files_sharing/lib/Sharing/LegacyBackend.php
new file mode 100644
index 0000000000000..2bbd53dadd6b3
--- /dev/null
+++ b/apps/files_sharing/lib/Sharing/LegacyBackend.php
@@ -0,0 +1,605 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Files_Sharing\Sharing;
+
+use DateTime;
+use DateTimeInterface;
+use NCU\Sharing\Exception\ShareNotFoundException;
+use NCU\Sharing\ISharingManager;
+use NCU\Sharing\Permission\ISharePermissionType;
+use NCU\Sharing\Permission\SharePermission;
+use NCU\Sharing\Recipient\IShareRecipientType;
+use NCU\Sharing\Recipient\ShareRecipient;
+use NCU\Sharing\Share;
+use NCU\Sharing\ShareState;
+use NCU\Sharing\ShareUser;
+use NCU\Sharing\Source\ShareSource;
+use OC\Core\Sharing\Permission\ReshareSharePermissionType;
+use OC\Core\Sharing\Property\ExpirationDateSharePropertyType;
+use OC\Core\Sharing\Property\LabelSharePropertyType;
+use OC\Core\Sharing\Property\NoteSharePropertyType;
+use OC\Core\Sharing\Recipient\EmailShareRecipientType;
+use OC\Core\Sharing\Recipient\GroupShareRecipientType;
+use OC\Core\Sharing\Recipient\TeamShareRecipientType;
+use OC\Core\Sharing\Recipient\TokenShareRecipientType;
+use OC\Core\Sharing\Recipient\UserShareRecipientType;
+use OC\Sharing\ISharingLegacyBackend;
+use OCA\Files\Sharing\Permission\NodeCreateSharePermissionType;
+use OCA\Files\Sharing\Permission\NodeDeleteSharePermissionType;
+use OCA\Files\Sharing\Permission\NodeDownloadSharePermissionType;
+use OCA\Files\Sharing\Permission\NodeReadSharePermissionType;
+use OCA\Files\Sharing\Permission\NodeUpdateSharePermissionType;
+use OCA\Files\Sharing\Source\NodeShareSourceType;
+use OCP\Constants;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\Federation\ICloudIdManager;
+use OCP\Files\File;
+use OCP\Files\IRootFolder;
+use OCP\Files\Node;
+use OCP\IDBConnection;
+use OCP\IUser;
+use OCP\L10N\IFactory;
+use OCP\Share\Exceptions\ShareNotFound;
+use OCP\Share\IManager;
+use OCP\Share\IShare;
+use OCP\Snowflake\ISnowflakeGenerator;
+use RuntimeException;
+
+// TODO: Implement accept/reject mechanism and password expiration time
+final readonly class LegacyBackend implements ISharingLegacyBackend {
+	public function __construct(
+		IFactory $factory,
+		private IDBConnection $connection,
+		private IRootFolder $rootFolder,
+		private IManager $legacyManager,
+		private ISnowflakeGenerator $snowflakeGenerator,
+		private ISharingManager $sharingManager,
+		private ICloudIdManager $cloudIdManager,
+	) {
+	}
+
+	#[\Override]
+	public function getCompatibleSourceTypes(): array {
+		return [NodeShareSourceType::class];
+	}
+
+	#[\Override]
+	public function getCompatibleRecipientTypes(): array {
+		return [
+			EmailShareRecipientType::class,
+			GroupShareRecipientType::class,
+			TeamShareRecipientType::class,
+			TokenShareRecipientType::class,
+			UserShareRecipientType::class,
+		];
+	}
+
+	#[\Override]
+	public function updateShare(Share $share): void {
+		$legacyShares = $this->getLegacyShares($share->id);
+
+		/** @var array<class-string<IShareRecipientType>, array<string, array<string, IShare>>> $legacyShareMapping */
+		$legacyShareMapping = [];
+		foreach ($legacyShares as $legacyShare) {
+			$recipientTypeClass = $this->legacyShareTypeToRecipientTypeClass($legacyShare->getShareType());
+			$sharedWith = $legacyShare->getSharedWith();
+			$legacyNodeId = (string)$legacyShare->getNodeId();
+
+			$legacyShareMapping[$recipientTypeClass] ??= [];
+			$legacyShareMapping[$recipientTypeClass][$sharedWith] ??= [];
+			$legacyShareMapping[$recipientTypeClass][$sharedWith][$legacyNodeId] = $legacyShare;
+		}
+
+		/** @var array<string, true> $validLegacyShares */
+		$validLegacyShares = [];
+		/** @var array<string, true> $updatedLegacyShares */
+		$updatedLegacyShares = [];
+		foreach ($share->recipients as $recipient) {
+			$legacyShareType = $this->recipientTypeClassToLegacyShareType($recipient->class, $recipient->instance);
+			foreach ($share->sources as $source) {
+				$create = false;
+				if (($legacyShare = $legacyShareMapping[$recipient->class][$recipient->value][$source->value] ?? null) === null) {
+					$legacyShare = $this->legacyManager->newShare();
+					$legacyShare->setShareType($legacyShareType);
+					$legacyShare->setNodeId((int)$source->value);
+					$legacyShare->setSharedWith($this->recipientToLegacySharedWith($recipient));
+
+					$this->setCommonFields($share, $legacyShare);
+					$create = true;
+				}
+
+				$update = false;
+
+
+				if ($recipient->instance !== null) {
+					throw new \Exception('Incoming remote shares aren\'t handled by ' . self::class);
+				}
+
+				if ($recipient->initiator !== null && $legacyShare->getSharedBy() !== $recipient->initiator->userId) {
+					$legacyShare->setSharedBy($recipient->initiator->userId);
+					$update = true;
+				}
+
+				[$permissions, $allowDownload] = $this->permissionsToLegacyPermission($source, array_keys($share->getEnabledPermissions()));
+				if ($legacyShare->getPermissions() !== $permissions) {
+					$legacyShare->setPermissions($permissions);
+					$update = true;
+				}
+
+				if ($legacyShare->getShareType() === IShare::TYPE_LINK || $legacyShare->getShareType() === IShare::TYPE_EMAIL) {
+					if ($legacyShare->getHideDownload() !== !$allowDownload) {
+						$legacyShare->setHideDownload(!$allowDownload);
+						$update = true;
+					}
+				} else {
+					$attributes = $legacyShare->getAttributes() ?? $legacyShare->newAttributes();
+					if ($attributes->getAttribute('permissions', 'download') !== !$allowDownload) {
+						$attributes->setAttribute('permissions', 'download', true);
+						$legacyShare->setAttributes($attributes);
+						$update = true;
+					}
+				}
+
+				$token = $recipient->secret ?? '';
+				if (in_array($recipient->class, [EmailShareRecipientType::class, TokenShareRecipientType::class], true) && $legacyShare->getToken() !== $token) {
+					$legacyShare->setToken($token);
+					$update = true;
+				}
+
+				if ($create) {
+					$legacyShare = $this->legacyManager->createShare($legacyShare);
+					// No need to insert the legacy full id, because the listener in the SharingManager will already trigger this process.
+					$legacyShares[$legacyShare->getFullId()] = $legacyShare;
+				} elseif ($update) {
+					$updatedLegacyShares[$legacyShare->getFullId()] = true;
+					$legacyShares[$legacyShare->getFullId()] = $legacyShare;
+				}
+
+				$validLegacyShares[$legacyShare->getFullId()] = true;
+			}
+		}
+
+		$invalidLegacyShares = array_diff(array_keys($legacyShares), array_keys($validLegacyShares));
+		foreach ($invalidLegacyShares as $invalidLegacyShareId) {
+			$this->deleteShare($invalidLegacyShareId);
+			unset($legacyShares[$invalidLegacyShareId]);
+		}
+
+		foreach ($legacyShares as $legacyShare) {
+			$update = $this->setCommonFields($share, $legacyShare);
+
+			if ($update || ($updatedLegacyShares[$legacyShare->getFullId()] ?? false)) {
+				$this->legacyManager->updateShare($legacyShare, false);
+			}
+		}
+	}
+
+	private function setCommonFields(Share $share, IShare $legacyShare): bool {
+		$update = false;
+
+		if ($share->owner->instance !== null) {
+			throw new \Exception('Incoming remote shares aren\'t handled by ' . self::class);
+		}
+		if ($legacyShare->getShareOwner() !== $share->owner->userId) {
+			$legacyShare->setShareOwner($share->owner->userId);
+			$update = true;
+		}
+
+		// TODO: Implement accept/reject mechanism
+		$status = IShare::STATUS_ACCEPTED;
+		if ($legacyShare->getShareType() === IShare::TYPE_USER && $legacyShare->getStatus() !== $status) {
+			$legacyShare->setStatus($status);
+			$update = true;
+		}
+
+		$note = $share->properties[NoteSharePropertyType::class]?->value ?? '';
+		if ($legacyShare->getNote() !== $note) {
+			$legacyShare->setNote($note);
+			$update = true;
+		}
+
+		$label = $share->properties[LabelSharePropertyType::class]?->value ?? '';
+		if (($legacyShare->getShareType() === IShare::TYPE_LINK || $legacyShare->getShareType() === IShare::TYPE_EMAIL) && $legacyShare->getLabel() !== $label) {
+			$legacyShare->setLabel($label);
+			$update = true;
+		}
+
+		$expirationDateProperty = $share->properties[ExpirationDateSharePropertyType::class] ?? null;
+		$expirationDate = $expirationDateProperty?->value;
+		if ($expirationDate !== null) {
+			$expirationDate = DateTime::createFromFormat(DateTimeInterface::ATOM, $expirationDate);
+		}
+
+		if ($legacyShare->getExpirationDate()?->getTimestamp() !== $expirationDate?->getTimestamp()) {
+			$legacyShare->setExpirationDate($expirationDate);
+			$update = true;
+		}
+
+		// The value and applying a default value is already handled by Unified Sharing.
+		if ($expirationDate === null && !$legacyShare->getNoExpirationDate()) {
+			$legacyShare->setNoExpirationDate(true);
+			$update = true;
+		}
+
+		// TODO: Update details that are the same for all legacy shares
+
+		return $update;
+	}
+
+	/**
+	 * @param list<class-string<ISharePermissionType>> $permissions
+	 * @return array{int-mask-of<Constants::PERMISSION_*>, bool}
+	 */
+	private function permissionsToLegacyPermission(ShareSource $source, array $permissions): array {
+		$node = $this->rootFolder->getFirstNodeById((int)$source->value);
+		if (!$node instanceof Node) {
+			throw new RuntimeException('Share source does not exist: ' . $source->value);
+		}
+
+		$nodeIsFile = $node instanceof File;
+
+		/** @var int-mask-of<Constants::PERMISSION_*> $legacyPermissions */
+		$legacyPermissions = 0;
+		$allowDownload = false;
+
+		if (in_array(NodeReadSharePermissionType::class, $permissions, true)) {
+			$legacyPermissions |= Constants::PERMISSION_READ;
+		}
+
+		if (in_array(NodeUpdateSharePermissionType::class, $permissions, true)) {
+			$legacyPermissions |= Constants::PERMISSION_UPDATE;
+		}
+
+		if (!$nodeIsFile && in_array(NodeCreateSharePermissionType::class, $permissions, true)) {
+			$legacyPermissions |= Constants::PERMISSION_CREATE;
+		}
+
+		if (!$nodeIsFile && in_array(NodeDeleteSharePermissionType::class, $permissions, true)) {
+			$legacyPermissions |= Constants::PERMISSION_DELETE;
+		}
+
+		if (in_array(ReshareSharePermissionType::class, $permissions, true)) {
+			$legacyPermissions |= Constants::PERMISSION_SHARE;
+		}
+
+		if (in_array(NodeDownloadSharePermissionType::class, $permissions, true)) {
+			$allowDownload = true;
+		}
+
+		return [$legacyPermissions, $allowDownload];
+	}
+
+	/**
+	 * @param int-mask-of<Constants::PERMISSION_*> $legacyPermissions
+	 * @return list<class-string<ISharePermissionType>>
+	 */
+	private function legacyPermissionsToPermissions(int $legacyPermissions, bool $allowDownload): array {
+		$permissions = [];
+
+		foreach ([
+			NodeReadSharePermissionType::class => Constants::PERMISSION_READ,
+			NodeUpdateSharePermissionType::class => Constants::PERMISSION_UPDATE,
+			NodeCreateSharePermissionType::class => Constants::PERMISSION_CREATE,
+			NodeDeleteSharePermissionType::class => Constants::PERMISSION_DELETE,
+			ReshareSharePermissionType::class => Constants::PERMISSION_SHARE,
+		] as $permissionTypeClass => $mask) {
+			if (($legacyPermissions & $mask) === $mask) {
+				$permissions[] = $permissionTypeClass;
+			}
+		}
+
+		if ($allowDownload) {
+			$permissions[] = NodeDownloadSharePermissionType::class;
+		}
+
+		return $permissions;
+	}
+
+	#[\Override]
+	public function deleteShare(string $id): void {
+		foreach ($this->getLegacyFullIds($id) as $legacyShareId) {
+			try {
+				$this->legacyManager->deleteShare($this->legacyManager->getShareById($legacyShareId, null, false));
+				$this->removeLegacyFullId($legacyShareId);
+			} catch (ShareNotFound) {
+				throw new ShareNotFoundException();
+			}
+		}
+	}
+
+	#[\Override]
+	public function getShare(string $id): Share {
+		$legacyShareIds = $this->getLegacyFullIds($id);
+		if ($legacyShareIds === []) {
+			throw new ShareNotFoundException();
+		}
+
+		$sources = [];
+		$recipients = [];
+
+		$legacyShares = array_map(fn (string $legacyShareId): IShare => $this->legacyManager->getShareById($legacyShareId, null, false), $legacyShareIds);
+
+		foreach ($legacyShares as $legacyShare) {
+			$nodeId = $legacyShare->getNodeId();
+			$sources[$nodeId] ??= new ShareSource(NodeShareSourceType::class, (string)$nodeId);
+
+			$recipientTypeClass = $this->legacyShareTypeToRecipientTypeClass($legacyShare->getShareType());
+			$isTokenRecipient = $recipientTypeClass === TokenShareRecipientType::class;
+			$recipients[$recipientTypeClass] ??= [];
+			$uniqueId = $isTokenRecipient ? $legacyShare->getToken() : $legacyShare->getSharedWith();
+			$recipient = $this->splitLegacySharedWith($legacyShare->getShareType(), $legacyShare->getSharedWith());
+			/** @psalm-suppress ArgumentTypeCoercion */
+			$recipients[$recipientTypeClass][$uniqueId] ??= new ShareRecipient(
+				$recipientTypeClass,
+				$recipient['value'],
+				$recipient['remote'],
+				$isTokenRecipient ? $legacyShare->getToken() : $this->sharingManager->generateSecret(),
+				new ShareUser(
+					$legacyShare->getSharedBy(),
+					// Incoming remote shares aren't handled by this
+					null,
+				),
+			);
+		}
+
+
+		if (!$this->checkAllSame($legacyShares, fn (IShare $share) => $share->getShareOwner())) {
+			throw new \Exception('All legacy shares sharing a share id don\'t have the same owner');
+		}
+
+		/** @psalm-suppress ArgumentTypeCoercion */
+		$owner = new ShareUser(
+			$legacyShares[0]->getShareOwner(),
+			// Incoming remote shares aren't handled by this
+			null,
+		);
+
+		// TODO
+		$properties = [];
+
+		if (!$this->checkAllSame($legacyShares, fn (IShare $share) => $share->getAttributes())) {
+			throw new \Exception('All legacy shares sharing a share id don\'t have the same attributes');
+		}
+		if (!$this->checkAllSame($legacyShares, fn (IShare $share) => $share->getPermissions())) {
+			throw new \Exception('All legacy shares sharing a share id don\'t have the same permissions');
+		}
+
+		$allowDownload = $legacyShares[0]->getShareType() === IShare::TYPE_LINK || $legacyShares[0]->getShareType() === IShare::TYPE_EMAIL
+			? !$legacyShares[0]->getHideDownload()
+			: $legacyShares[0]->getAttributes()?->getAttribute('permissions', 'download') === true;
+		$enabledPermissions = $this->legacyPermissionsToPermissions($legacyShares[0]->getPermissions(), $allowDownload);
+		$permissions = [];
+		foreach ([
+			NodeReadSharePermissionType::class,
+			NodeUpdateSharePermissionType::class,
+			NodeCreateSharePermissionType::class,
+			NodeDeleteSharePermissionType::class,
+			ReshareSharePermissionType::class,
+			NodeDownloadSharePermissionType::class,
+		] as $permissionTypeClass) {
+			$permissions[$permissionTypeClass] = new SharePermission($permissionTypeClass, in_array($permissionTypeClass, $enabledPermissions, true));
+		}
+
+		/** @psalm-suppress ArgumentTypeCoercion */
+		return new Share(
+			$id,
+			$owner,
+			\DateTimeImmutable::createFromMutable($legacyShares[0]->getShareTime()),
+			// TODO
+			ShareState::Active,
+			array_values($sources),
+			array_merge(...array_values($recipients)),
+			$properties,
+			$permissions,
+		);
+	}
+
+	/**
+	 * Check that all items return the same result when used as argument to a function
+	 *
+	 * @template T
+	 * @param iterable<T> $items
+	 * @param callable(T):mixed $fn
+	 * @return bool
+	 */
+	private function checkAllSame(iterable $items, callable $fn): bool {
+		$first = true;
+		$commonValue = null;
+		foreach ($items as $item) {
+			$value = $fn($item);
+			if ($first) {
+				$commonValue = $value;
+				$first = false;
+			} elseif ($value !== $commonValue) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	#[\Override]
+	public function getShareByLegacyProviderAndId(string $legacyProvider, string $legacyId): Share {
+		$id = $this->getId($legacyProvider, $legacyId);
+		if ($id === null) {
+			throw new ShareNotFoundException();
+		}
+
+		return $this->getShare($id);
+	}
+
+	#[\Override]
+	public function getUnmappedShares(IUser $user): array {
+		// TODO: Make it work with all providers
+		// TODO: Filter by user
+		$qb = $this->connection->getQueryBuilder();
+		$result = $qb
+			->select('s.id')
+			->from('share', 's')
+			->leftJoin('s', 'share_legacy_mapping', 'l', $qb->expr()->eq('s.id', 'l.legacy_id'))
+			->where($qb->expr()->isNull('l.legacy_id'))
+			->andWhere($qb->expr()->in('s.share_type', $qb->createNamedParameter([
+				IShare::TYPE_USER,
+				IShare::TYPE_REMOTE,
+				IShare::TYPE_GROUP,
+				IShare::TYPE_REMOTE_GROUP,
+				IShare::TYPE_LINK,
+				IShare::TYPE_EMAIL,
+				IShare::TYPE_CIRCLE,
+			], IQueryBuilder::PARAM_INT_ARRAY)))
+			->executeQuery();
+
+		/** @var list<int> $legacyIds */
+		$legacyIds = $result->fetchFirstColumn();
+		if ($legacyIds === []) {
+			return [];
+		}
+
+		$ids = [];
+		foreach ($legacyIds as $legacyId) {
+			$id = $this->snowflakeGenerator->nextId();
+			$this->addLegacyFullId($id, 'ocinternal', (string)$legacyId);
+			$ids[] = $id;
+		}
+
+		return array_map($this->getShare(...), $ids);
+	}
+
+	/**
+	 * @return list<string>
+	 */
+	public function getLegacyFullIds(string $id): array {
+		$qb = $this->connection->getQueryBuilder();
+		$result = $qb
+			->select('legacy_provider', 'legacy_id')
+			->from('share_legacy_mapping')
+			->where($qb->expr()->eq('id', $qb->createNamedParameter($id)))
+			->executeQuery();
+
+		/** @var list<array{legacy_provider: string, legacy_id: string}> $rows */
+		$rows = $result->fetchAllAssociative();
+
+		return array_map(static fn (array $row): string => $row['legacy_provider'] . ':' . $row['legacy_id'], $rows);
+	}
+
+	private function getId(string $legacyProvider, string $legacyId): ?string {
+		$qb = $this->connection->getQueryBuilder();
+		$result = $qb
+			->select('id')
+			->from('share_legacy_mapping')
+			->where($qb->expr()->eq('legacy_provider', $qb->createNamedParameter($legacyProvider)))
+			->andWhere($qb->expr()->eq('legacy_id', $qb->createNamedParameter($legacyId)))
+			->executeQuery();
+
+		/** @var int|false $id */
+		$id = $result->fetchOne();
+		if ($id === false) {
+			return null;
+		}
+
+		return (string)$id;
+	}
+
+	/**
+	 * @return array<string, IShare>
+	 */
+	private function getLegacyShares(string $id): array {
+		$legacyIds = $this->getLegacyFullIds($id);
+
+		$shares = [];
+		foreach ($legacyIds as $legacyFullId) {
+			try {
+				$shares[$legacyFullId] = $this->legacyManager->getShareById($legacyFullId, null, false);
+			} catch (ShareNotFound) {
+				$this->removeLegacyFullId($legacyFullId);
+			}
+		}
+
+		return $shares;
+	}
+
+	private function removeLegacyFullId(string $legacyFullId): void {
+		[$providerId, $shareId] = explode(':', $legacyFullId);
+
+		$qb = $this->connection->getQueryBuilder();
+		$qb
+			->delete('share_legacy_mapping')
+			->where($qb->expr()->eq('legacy_provder', $qb->createNamedParameter($providerId)))
+			->where($qb->expr()->eq('legacy_id', $qb->createNamedParameter($shareId)))
+			->executeStatement();
+	}
+
+	private function addLegacyFullId(string $id, string $legacyProvider, string $legacyId): void {
+		$qb = $this->connection->getQueryBuilder();
+		$qb
+			->insert('share_legacy_mapping')
+			->values([
+				'id' => $qb->createNamedParameter($id),
+				'legacy_provider' => $qb->createNamedParameter($legacyProvider),
+				'legacy_id' => $qb->createNamedParameter($legacyId),
+			])
+			->executeStatement();
+	}
+
+	/**
+	 * @param IShare::TYPE_* $legacyShareType
+	 * @return class-string<IShareRecipientType>
+	 */
+	private function legacyShareTypeToRecipientTypeClass(int $legacyShareType): string {
+		return match ($legacyShareType) {
+			IShare::TYPE_USER, IShare::TYPE_REMOTE => UserShareRecipientType::class,
+			IShare::TYPE_GROUP, IShare::TYPE_REMOTE_GROUP => GroupShareRecipientType::class,
+			IShare::TYPE_LINK => TokenShareRecipientType::class,
+			IShare::TYPE_EMAIL => EmailShareRecipientType::class,
+			IShare::TYPE_CIRCLE => TeamShareRecipientType::class,
+			default => throw new RuntimeException('Unsupported legacy share type: ' . $legacyShareType),
+		};
+	}
+
+	/**
+	 * @param class-string<IShareRecipientType> $recipientTypeClass
+	 * @return IShare::TYPE_*
+	 */
+	private function recipientTypeClassToLegacyShareType(string $recipientTypeClass, ?string $instance): int {
+		return match ($recipientTypeClass) {
+			UserShareRecipientType::class => $instance === null ? IShare::TYPE_USER : IShare::TYPE_REMOTE,
+			GroupShareRecipientType::class => $instance === null ? IShare::TYPE_GROUP : IShare::TYPE_REMOTE_GROUP,
+			TokenShareRecipientType::class => IShare::TYPE_LINK,
+			EmailShareRecipientType::class => IShare::TYPE_EMAIL,
+			TeamShareRecipientType::class => IShare::TYPE_CIRCLE,
+			default => throw new RuntimeException('Unsupported recipient type: ' . $recipientTypeClass),
+		};
+	}
+
+	private function recipientToLegacySharedWith(ShareRecipient $recipient): string {
+		if ($recipient->class === TokenShareRecipientType::class) {
+			return $this->cloudIdManager->getCloudId($recipient->value, $recipient->instance)->getId();
+		} else {
+			return $recipient->value;
+		}
+	}
+
+	/**
+	 * @return array{value: string, remote: string|null}
+	 */
+	private function splitLegacySharedWith(int $shareType, string $sharedWith): array {
+		if ($shareType === IShare::TYPE_REMOTE || $shareType === IShare::TYPE_REMOTE_GROUP) {
+			$cloudId = $this->cloudIdManager->resolveCloudId($sharedWith);
+			return [
+				'value' => $cloudId->getUser(),
+				'remote' => $cloudId->getRemote(),
+			];
+		} else {
+			return [
+				'value' => $sharedWith,
+				'remote' => null,
+			];
+		}
+	}
+}
diff --git a/apps/files_sharing/tests/Sharing/LegacyBackendTest.php b/apps/files_sharing/tests/Sharing/LegacyBackendTest.php
new file mode 100644
index 0000000000000..b5a29b953a00f
--- /dev/null
+++ b/apps/files_sharing/tests/Sharing/LegacyBackendTest.php
@@ -0,0 +1,661 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Files_Sharing\Tests\Sharing;
+
+use DateInterval;
+use DateTimeImmutable;
+use DateTimeInterface;
+use OC\Core\Sharing\Permission\ReshareSharePermissionType;
+use OC\Core\Sharing\Property\ExpirationDateSharePropertyType;
+use OC\Core\Sharing\Property\LabelSharePropertyType;
+use OC\Core\Sharing\Property\NoteSharePropertyType;
+use OC\Core\Sharing\Recipient\EmailShareRecipientType;
+use OC\Core\Sharing\Recipient\GroupShareRecipientType;
+use OC\Core\Sharing\Recipient\TeamShareRecipientType;
+use OC\Core\Sharing\Recipient\TokenShareRecipientType;
+use OC\Core\Sharing\Recipient\UserShareRecipientType;
+use OC\Sharing\ISharingLegacyBackend;
+use OCA\Circles\CirclesManager;
+use OCA\Circles\Service\CircleService;
+use OCA\Files\Sharing\Permission\NodeCreateSharePermissionType;
+use OCA\Files\Sharing\Permission\NodeDeleteSharePermissionType;
+use OCA\Files\Sharing\Permission\NodeDownloadSharePermissionType;
+use OCA\Files\Sharing\Permission\NodeReadSharePermissionType;
+use OCA\Files\Sharing\Permission\NodeUpdateSharePermissionType;
+use OCA\Files\Sharing\Source\NodeShareSourceType;
+use OCA\Files_Sharing\Sharing\LegacyBackend;
+use OCP\Constants;
+use OCP\Federation\ICloudIdManager;
+use OCP\Files\IRootFolder;
+use OCP\IDBConnection;
+use OCP\IGroupManager;
+use OCP\IUserManager;
+use OCP\L10N\IFactory;
+use OCP\Server;
+use OCP\Share\IManager;
+use OCP\Share\IShare;
+use OCP\Sharing\ISharingManager;
+use OCP\Sharing\Permission\SharePermission;
+use OCP\Sharing\Property\ShareProperty;
+use OCP\Sharing\Recipient\ShareRecipient;
+use OCP\Sharing\Share;
+use OCP\Sharing\ShareState;
+use OCP\Sharing\ShareUser;
+use OCP\Sharing\Source\ShareSource;
+use OCP\Snowflake\ISnowflakeGenerator;
+use PHPUnit\Framework\Attributes\Group;
+use Test\TestCase;
+
+#[Group(name: 'DB')]
+final class LegacyBackendTest extends TestCase {
+	private IManager $legacyManager;
+
+	private IDBConnection $dbConnection;
+
+	private ISharingLegacyBackend $legacyBackend;
+
+	#[\Override]
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->legacyManager = Server::get(IManager::class);
+		$this->dbConnection = Server::get(IDBConnection::class);
+
+		$this->legacyBackend = new LegacyBackend(
+			Server::get(IFactory::class),
+			$this->dbConnection,
+			Server::get(IRootFolder::class),
+			$this->legacyManager,
+			Server::get(ISnowflakeGenerator::class),
+			Server::get(ISharingManager::class),
+			Server::get(ICloudIdManager::class),
+		);
+	}
+
+	#[\Override]
+	protected function tearDown(): void {
+		foreach ([
+			'share',
+			'share_external',
+			'share_legacy_mapping',
+		] as $table) {
+			$qb = $this->dbConnection->getQueryBuilder();
+			$qb
+				->select($qb->func()->count('*'))
+				->from($table);
+			$this->assertEquals(0, $qb->executeQuery()->fetchOne(), $table);
+		}
+
+		parent::tearDown();
+	}
+
+	public function testUpdateShare(): void {
+		$userManager = Server::get(IUserManager::class);
+		$groupManager = Server::get(IGroupManager::class);
+
+		$owner = $userManager->createUser('owner', 'password');
+		$this->assertNotFalse($owner);
+		$this->assertTrue($owner->setDisplayName('Owner'));
+
+		$user = $userManager->createUser('user', 'password');
+		$this->assertNotFalse($user);
+		$this->assertTrue($user->setDisplayName('User'));
+
+		$group = $groupManager->createGroup('group');
+		$this->assertNotNull($group);
+		$this->assertTrue($group->setDisplayName('Group'));
+		// Clear display name cache, because setting the display name on the group doesn't update it in the cache of the manager
+		self::invokePrivate(self::invokePrivate($groupManager, 'displayNameCache'), 'clear');
+
+		$circle = null;
+		if (class_exists(CirclesManager::class)) {
+			$circlesManager = Server::get(CirclesManager::class);
+			$circlesManager->startSession($circlesManager->getLocalFederatedUser($owner->getUID()));
+			/** @psalm-suppress MixedAssignment */
+			$circle = $circlesManager->createCircle('circle');
+			/** @psalm-suppress MixedMethodCall, UndefinedClass */
+			Server::get(CircleService::class)->updateName($circle->getSingleId(), 'Circle');
+			/** @psalm-suppress MixedMethodCall, MixedAssignment */
+			$circle = $circlesManager->getCircle($circle->getSingleId());
+		}
+
+		$node1 = Server::get(IRootFolder::class)->getUserFolder($owner->getUID())->newFolder('foo');
+
+		$node2 = Server::get(IRootFolder::class)->getUserFolder($owner->getUID())->newFile('foo.txt');
+
+		// TODO: Accept arbitrary expiration dates.
+		$expirationDate = (new DateTimeImmutable())->add(new DateInterval('P1D'))->setTime(23, 59, 59)->format(DateTimeInterface::ATOM);
+
+		// TODO: Test federated owner.
+		/** @psalm-suppress MixedMethodCall, MixedArgument */
+		$share = new Share(
+			'123',
+			new ShareUser(
+				$owner->getUID(),
+				null,
+			),
+			0,
+			ShareState::Active,
+			[
+				new ShareSource(
+					NodeShareSourceType::class,
+					(string)$node1->getId(),
+				),
+				new ShareSource(
+					NodeShareSourceType::class,
+					(string)$node2->getId(),
+				),
+			],
+			array_merge(
+				[
+					// TODO: Test federation
+					new ShareRecipient(
+						UserShareRecipientType::class,
+						$user->getUID(),
+						null,
+						'user secret',
+						new ShareUser(
+							$owner->getUID(),
+							null,
+						),
+					),
+					// TODO: Test federation
+					new ShareRecipient(
+						GroupShareRecipientType::class,
+						$group->getGID(),
+						null,
+						'group secret',
+						new ShareUser(
+							$owner->getUID(),
+							null,
+						),
+					),
+					new ShareRecipient(
+						TokenShareRecipientType::class,
+						'token',
+						null,
+						'token secret',
+						new ShareUser(
+							$owner->getUID(),
+							null,
+						),
+					),
+					new ShareRecipient(
+						EmailShareRecipientType::class,
+						'example@example.com',
+						null,
+						'email secret',
+						new ShareUser(
+							$owner->getUID(),
+							null,
+						),
+					),
+				],
+				$circle !== null ? [
+					new ShareRecipient(
+						TeamShareRecipientType::class,
+						$circle->getSingleId(),
+						null,
+						'team secret',
+						new ShareUser(
+							$owner->getUID(),
+							null,
+						),
+					),
+				] : [],
+			),
+			[
+				NoteSharePropertyType::class => new ShareProperty(
+					NoteSharePropertyType::class,
+					'Note',
+				),
+				ExpirationDateSharePropertyType::class => new ShareProperty(
+					ExpirationDateSharePropertyType::class,
+					$expirationDate,
+				),
+				LabelSharePropertyType::class => new ShareProperty(
+					LabelSharePropertyType::class,
+					'Label',
+				),
+				// TODO: Test all property types
+			],
+			[
+				NodeReadSharePermissionType::class => new SharePermission(
+					NodeReadSharePermissionType::class,
+					true,
+				),
+				NodeUpdateSharePermissionType::class => new SharePermission(
+					NodeUpdateSharePermissionType::class,
+					true,
+				),
+				NodeCreateSharePermissionType::class => new SharePermission(
+					NodeCreateSharePermissionType::class,
+					true,
+				),
+				NodeDeleteSharePermissionType::class => new SharePermission(
+					NodeDeleteSharePermissionType::class,
+					true,
+				),
+				ReshareSharePermissionType::class => new SharePermission(
+					ReshareSharePermissionType::class,
+					true,
+				),
+				NodeDownloadSharePermissionType::class => new SharePermission(
+					NodeDownloadSharePermissionType::class,
+					true,
+				),
+			],
+		);
+
+		$this->legacyBackend->updateShare($share);
+
+		$legacyIds = $this->getLegacyIds($share->id);
+		usort($legacyIds, static fn (string $a, string $b): int => explode(':', $a)[1] <=> explode(':', $b)[1]);
+		$legacyShares = array_map(fn (string $legacyId): array => $this->formatLegacyShare($this->legacyManager->getShareById($legacyId)), $legacyIds);
+		/** @psalm-suppress MixedMethodCall, MixedOperand */
+		$this->assertEquals(array_merge(
+			[
+				[
+					'id' => explode(':', $legacyIds[0])[1],
+					'full_id' => $legacyIds[0],
+					'node_id' => $node1->getId(),
+					'node_type' => 'folder',
+					'share_type' => IShare::TYPE_USER,
+					'shared_with' => $user->getUID(),
+					'shared_with_display_name' => $user->getDisplayName(),
+					'shared_with_avatar' => null,
+					'permissions' => Constants::PERMISSION_ALL,
+					'attributes' => [
+						[
+							'scope' => 'permissions',
+							'key' => 'download',
+							'value' => true,
+						]
+					],
+					'status' => IShare::STATUS_ACCEPTED,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => '',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => null,
+					'parent' => null,
+					'original_target' => null,
+					'target' => '/foo',
+					'mail_send' => false,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+				[
+					'id' => explode(':', $legacyIds[1])[1],
+					'full_id' => $legacyIds[1],
+					'node_id' => $node2->getId(),
+					'node_type' => 'file',
+					'share_type' => IShare::TYPE_USER,
+					'shared_with' => $user->getUID(),
+					'shared_with_display_name' => $user->getDisplayName(),
+					'shared_with_avatar' => null,
+					'permissions' => Constants::PERMISSION_ALL & ~Constants::PERMISSION_CREATE & ~Constants::PERMISSION_DELETE,
+					'attributes' => [
+						[
+							'scope' => 'permissions',
+							'key' => 'download',
+							'value' => true,
+						]
+					],
+					'status' => IShare::STATUS_ACCEPTED,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => '',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => null,
+					'parent' => null,
+					'original_target' => null,
+					'target' => '/foo.txt',
+					'mail_send' => false,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+				[
+					'id' => explode(':', $legacyIds[2])[1],
+					'full_id' => $legacyIds[2],
+					'node_id' => $node1->getId(),
+					'node_type' => 'folder',
+					'share_type' => IShare::TYPE_GROUP,
+					'shared_with' => $group->getGID(),
+					'shared_with_display_name' => $group->getDisplayName(),
+					'shared_with_avatar' => null,
+					'permissions' => Constants::PERMISSION_ALL,
+					'attributes' => [
+						[
+							'scope' => 'permissions',
+							'key' => 'download',
+							'value' => true,
+						]
+					],
+					'status' => IShare::STATUS_PENDING,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => '',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => null,
+					'parent' => null,
+					'original_target' => null,
+					'target' => '/foo',
+					'mail_send' => false,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+				[
+					'id' => explode(':', $legacyIds[3])[1],
+					'full_id' => $legacyIds[3],
+					'node_id' => $node2->getId(),
+					'node_type' => 'file',
+					'share_type' => IShare::TYPE_GROUP,
+					'shared_with' => $group->getGID(),
+					'shared_with_display_name' => $group->getDisplayName(),
+					'shared_with_avatar' => null,
+					'permissions' => Constants::PERMISSION_ALL & ~Constants::PERMISSION_CREATE & ~Constants::PERMISSION_DELETE,
+					'attributes' => [
+						[
+							'scope' => 'permissions',
+							'key' => 'download',
+							'value' => true,
+						]
+					],
+					'status' => IShare::STATUS_PENDING,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => '',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => null,
+					'parent' => null,
+					'original_target' => null,
+					'target' => '/foo.txt',
+					'mail_send' => false,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+				[
+					'id' => explode(':', $legacyIds[4])[1],
+					'full_id' => $legacyIds[4],
+					'node_id' => $node1->getId(),
+					'node_type' => 'folder',
+					'share_type' => IShare::TYPE_LINK,
+					'shared_with' => null,
+					'shared_with_display_name' => '',
+					'shared_with_avatar' => null,
+					'permissions' => Constants::PERMISSION_ALL,
+					'attributes' => null,
+					'status' => IShare::STATUS_PENDING,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => 'Label',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => 'secret',
+					'parent' => null,
+					'original_target' => null,
+					'target' => '/foo',
+					'mail_send' => false,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+				[
+					'id' => explode(':', $legacyIds[5])[1],
+					'full_id' => $legacyIds[5],
+					'node_id' => $node2->getId(),
+					'node_type' => 'file',
+					'share_type' => IShare::TYPE_LINK,
+					'shared_with' => null,
+					'shared_with_display_name' => '',
+					'shared_with_avatar' => null,
+					'permissions' => Constants::PERMISSION_ALL & ~Constants::PERMISSION_CREATE & ~Constants::PERMISSION_DELETE,
+					'attributes' => null,
+					'status' => IShare::STATUS_PENDING,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => 'Label',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => 'secret',
+					'parent' => null,
+					'original_target' => null,
+					'target' => '/foo.txt',
+					'mail_send' => false,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+				[
+					'id' => explode(':', $legacyIds[6])[1],
+					'full_id' => $legacyIds[6],
+					'node_id' => $node1->getId(),
+					'node_type' => 'folder',
+					'share_type' => IShare::TYPE_EMAIL,
+					'shared_with' => 'example@example.com',
+					'shared_with_display_name' => '',
+					'shared_with_avatar' => null,
+					'permissions' => Constants::PERMISSION_ALL,
+					'attributes' => null,
+					'status' => null,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => 'Label',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => 'secret',
+					'parent' => null,
+					'original_target' => null,
+					'target' => null,
+					'mail_send' => false,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+				[
+					'id' => explode(':', $legacyIds[7])[1],
+					'full_id' => $legacyIds[7],
+					'node_id' => $node2->getId(),
+					'node_type' => 'file',
+					'share_type' => IShare::TYPE_EMAIL,
+					'shared_with' => 'example@example.com',
+					'shared_with_display_name' => '',
+					'shared_with_avatar' => null,
+					'permissions' => Constants::PERMISSION_ALL & ~Constants::PERMISSION_CREATE & ~Constants::PERMISSION_DELETE,
+					'attributes' => null,
+					'status' => null,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => 'Label',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => 'secret',
+					'parent' => null,
+					'original_target' => null,
+					'target' => null,
+					'mail_send' => false,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+			],
+			$circle !== null ? [
+				[
+					'id' => explode(':', $legacyIds[8])[1],
+					'full_id' => $legacyIds[8],
+					'node_id' => $node1->getId(),
+					'node_type' => 'folder',
+					'share_type' => IShare::TYPE_CIRCLE,
+					'shared_with' => $circle->getSingleId(),
+					'shared_with_display_name' => $circle->getDisplayName() . ' (Team owned by ' . $owner->getDisplayName() . ')',
+					'shared_with_avatar' => 'http://localhost/apps/circles/img/circles.svg',
+					'permissions' => Constants::PERMISSION_ALL,
+					'attributes' => [
+						[
+							'scope' => 'permissions',
+							'key' => 'download',
+							'value' => true,
+						]
+					],
+					'status' => IShare::STATUS_ACCEPTED,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => '',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => '',
+					'parent' => null,
+					'original_target' => null,
+					'target' => '/foo',
+					'mail_send' => true,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+				[
+					'id' => explode(':', $legacyIds[9])[1],
+					'full_id' => $legacyIds[9],
+					'node_id' => $node2->getId(),
+					'node_type' => 'file',
+					'share_type' => IShare::TYPE_CIRCLE,
+					'shared_with' => $circle->getSingleId(),
+					'shared_with_display_name' => $circle->getDisplayName() . ' (Team owned by ' . $owner->getDisplayName() . ')',
+					'shared_with_avatar' => 'http://localhost/apps/circles/img/circles.svg',
+					'permissions' => Constants::PERMISSION_ALL & ~Constants::PERMISSION_CREATE & ~Constants::PERMISSION_DELETE,
+					'attributes' => [
+						[
+							'scope' => 'permissions',
+							'key' => 'download',
+							'value' => true,
+						]
+					],
+					'status' => IShare::STATUS_ACCEPTED,
+					'note' => 'Note',
+					'expiration_date' => $expirationDate,
+					'no_expiration_date' => false,
+					'label' => '',
+					'shared_by' => 'owner',
+					'share_owner' => 'owner',
+					'password' => null,
+					'password_expiration_time' => null,
+					'send_password_by_talk' => false,
+					'token' => '',
+					'parent' => null,
+					'original_target' => null,
+					'target' => '/foo.txt',
+					'mail_send' => true,
+					'hide_download' => false,
+					'reminder_sent' => false,
+				],
+			] : [],
+		), $legacyShares);
+
+		$this->legacyBackend->deleteShare($share->id);
+		if (class_exists(CirclesManager::class) && $circle !== null) {
+			$circlesManager = Server::get(CirclesManager::class);
+			$circlesManager->startSession($circlesManager->getLocalFederatedUser($owner->getUID()));
+			/** @psalm-suppress MixedMethodCall */
+			$circlesManager->destroyCircle($circle->getSingleId());
+		}
+
+		$this->assertTrue($group->delete());
+		$this->assertTrue($user->delete());
+		$this->assertTrue($owner->delete());
+	}
+
+	/**
+	 * @return array<string, string|int|bool|mixed[]|null>
+	 */
+	private function formatLegacyShare(IShare $legacyShare): array {
+		// Omitted, because it is not predictable
+		$this->assertGreaterThan(0, $legacyShare->getShareTime()->getTimestamp());
+
+		return [
+			'id' => $legacyShare->getId(),
+			'full_id' => $legacyShare->getFullId(),
+			'node_id' => $legacyShare->getNodeId(),
+			'node_type' => $legacyShare->getNodeType(),
+			'share_type' => $legacyShare->getShareType(),
+			'shared_with' => $legacyShare->getSharedWith(),
+			'shared_with_display_name' => $legacyShare->getSharedWithDisplayName(),
+			'shared_with_avatar' => $legacyShare->getSharedWithAvatar(),
+			'permissions' => $legacyShare->getPermissions(),
+			'attributes' => $legacyShare->getAttributes()?->toArray(),
+			'status' => $legacyShare->getStatus(),
+			'note' => $legacyShare->getNote(),
+			'expiration_date' => $legacyShare->getExpirationDate()?->format(DateTimeInterface::ATOM),
+			'no_expiration_date' => $legacyShare->getNoExpirationDate(),
+			'label' => $legacyShare->getLabel(),
+			'shared_by' => $legacyShare->getSharedBy(),
+			'share_owner' => $legacyShare->getShareOwner(),
+			'password' => $legacyShare->getPassword(),
+			'password_expiration_time' => $legacyShare->getPasswordExpirationTime()?->format(DateTimeInterface::ATOM),
+			'send_password_by_talk' => $legacyShare->getSendPasswordByTalk(),
+			'token' => $legacyShare->getToken(),
+			'parent' => $legacyShare->getParent(),
+			'original_target' => $legacyShare->getOriginalTarget(),
+			'target' => $legacyShare->getTarget(),
+			'mail_send' => $legacyShare->getMailSend(),
+			'hide_download' => $legacyShare->getHideDownload(),
+			'reminder_sent' => $legacyShare->getReminderSent(),
+		];
+	}
+
+	/**
+	 * @return list<string>
+	 */
+	private function getLegacyIds(string $id): array {
+		$qb = $this->dbConnection->getQueryBuilder();
+		$result = $qb
+			->select('legacy_id')
+			->from('share_legacy_mapping')
+			->where($qb->expr()->eq('id', $qb->createNamedParameter($id)))
+			->executeQuery();
+		/** @var list<string> $ids */
+		$ids = $result->fetchFirstColumn();
+		return $ids;
+	}
+}
diff --git a/build/rector-strict.php b/build/rector-strict.php
index db161bfd07bb0..bc547d1f267d7 100644
--- a/build/rector-strict.php
+++ b/build/rector-strict.php
@@ -47,6 +47,8 @@
 		$nextcloudDir . '/tests/Core/Sharing',
 		$nextcloudDir . '/apps/files/lib/Sharing',
 		$nextcloudDir . '/apps/files/tests/Sharing',
+		$nextcloudDir . '/apps/files_sharing/lib/Sharing',
+		$nextcloudDir . '/apps/files_sharing/tests/Sharing',
 	])
 	->withAutoloadPaths([
 		// ensure rector properly autoload the public interfaces
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index 79825014fdffc..f661fe8152658 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -896,6 +896,7 @@
     'OCP\\SetupCheck\\ISetupCheckManager' => $baseDir . '/lib/public/SetupCheck/ISetupCheckManager.php',
     'OCP\\SetupCheck\\SetupResult' => $baseDir . '/lib/public/SetupCheck/SetupResult.php',
     'OCP\\Share' => $baseDir . '/lib/public/Share.php',
+    'OCP\\Share\\Events\\AfterShareModifiedEvent' => $baseDir . '/lib/public/Share/Events/AfterShareModifiedEvent.php',
     'OCP\\Share\\Events\\BeforeShareCreatedEvent' => $baseDir . '/lib/public/Share/Events/BeforeShareCreatedEvent.php',
     'OCP\\Share\\Events\\BeforeShareDeletedEvent' => $baseDir . '/lib/public/Share/Events/BeforeShareDeletedEvent.php',
     'OCP\\Share\\Events\\ShareAcceptedEvent' => $baseDir . '/lib/public/Share/Events/ShareAcceptedEvent.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index 260349ab1fdac..422bf9ccaf828 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -937,6 +937,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\SetupCheck\\ISetupCheckManager' => __DIR__ . '/../../..' . '/lib/public/SetupCheck/ISetupCheckManager.php',
         'OCP\\SetupCheck\\SetupResult' => __DIR__ . '/../../..' . '/lib/public/SetupCheck/SetupResult.php',
         'OCP\\Share' => __DIR__ . '/../../..' . '/lib/public/Share.php',
+        'OCP\\Share\\Events\\AfterShareModifiedEvent' => __DIR__ . '/../../..' . '/lib/public/Share/Events/AfterShareModifiedEvent.php',
         'OCP\\Share\\Events\\BeforeShareCreatedEvent' => __DIR__ . '/../../..' . '/lib/public/Share/Events/BeforeShareCreatedEvent.php',
         'OCP\\Share\\Events\\BeforeShareDeletedEvent' => __DIR__ . '/../../..' . '/lib/public/Share/Events/BeforeShareDeletedEvent.php',
         'OCP\\Share\\Events\\ShareAcceptedEvent' => __DIR__ . '/../../..' . '/lib/public/Share/Events/ShareAcceptedEvent.php',
diff --git a/lib/private/Share20/Manager.php b/lib/private/Share20/Manager.php
index f1b8dbc4ce97e..0278c5605230e 100644
--- a/lib/private/Share20/Manager.php
+++ b/lib/private/Share20/Manager.php
@@ -60,6 +60,7 @@
 use OCP\Security\PasswordContext;
 use OCP\Server;
 use OCP\Share;
+use OCP\Share\Events\AfterShareModifiedEvent;
 use OCP\Share\Events\BeforeShareCreatedEvent;
 use OCP\Share\Events\BeforeShareDeletedEvent;
 use OCP\Share\Events\ShareAcceptedEvent;
@@ -642,6 +643,7 @@ public function createShare(IShare $share): IShare {
 				$provider = $this->factory->getProviderForType($share->getShareType());
 				if ($provider instanceof IShareProviderWithNotification) {
 					$provider->sendMailNotification($share);
+					$this->dispatcher->dispatchTyped(new AfterShareModifiedEvent($share));
 				} else {
 					$this->logger->debug('Share notification not sent because the provider does not support it.', ['app' => 'share']);
 				}
@@ -753,6 +755,7 @@ public function updateShare(IShare $share, bool $onlyValid = true): IShare {
 		} else {
 			$share = $provider->update($share);
 		}
+		$this->dispatcher->dispatchTyped(new AfterShareModifiedEvent($share));
 
 		if ($expirationDateUpdated === true) {
 			\OC_Hook::emit(Share::class, 'post_set_expiration_date', [
@@ -1067,7 +1070,11 @@ public function restoreShare(IShare $share, string $recipientId): IShare {
 		[$providerId,] = $this->splitFullId($share->getFullId());
 		$provider = $this->factory->getProvider($providerId);
 
-		return $provider->restore($share, $recipientId);
+		$provider->restore($share, $recipientId);
+
+		$this->dispatcher->dispatchTyped(new AfterShareModifiedEvent($share));
+
+		return $share;
 	}
 
 	#[Override]
@@ -1449,6 +1456,8 @@ public function checkPassword(IShare $share, ?string $password): bool {
 			$share->setPassword($newHash);
 			$provider = $this->factory->getProviderForType($share->getShareType());
 			$provider->update($share);
+
+			$this->dispatcher->dispatchTyped(new AfterShareModifiedEvent($share));
 		}
 
 		return true;
diff --git a/lib/private/Share20/Share.php b/lib/private/Share20/Share.php
index d88710e4e191f..e018c3324d936 100644
--- a/lib/private/Share20/Share.php
+++ b/lib/private/Share20/Share.php
@@ -120,6 +120,15 @@ public function setProviderId(string $id): self {
 		return $this;
 	}
 
+	#[Override]
+	public function getProviderId(): string {
+		if ($this->providerId === null) {
+			throw new \UnexpectedValueException;
+		}
+
+		return $this->providerId;
+	}
+
 	#[Override]
 	public function setNode(Node $node): self {
 		$this->fileId = null;
diff --git a/lib/private/Sharing/ISharingLegacyBackend.php b/lib/private/Sharing/ISharingLegacyBackend.php
index 5aa9f45271e75..9c7774031ff19 100644
--- a/lib/private/Sharing/ISharingLegacyBackend.php
+++ b/lib/private/Sharing/ISharingLegacyBackend.php
@@ -12,8 +12,8 @@
 use NCU\Sharing\Exception\ShareNotFoundException;
 use NCU\Sharing\Recipient\IShareRecipientType;
 use NCU\Sharing\Share;
-use NCU\Sharing\ShareAccessContext;
 use NCU\Sharing\Source\IShareSourceType;
+use OCP\IUser;
 
 /**
  * This interface is only temporary and implemented in the files_sharing app.
@@ -46,14 +46,19 @@ public function deleteShare(string $id): void;
 	 *
 	 * @throws ShareNotFoundException
 	 */
-	public function getShare(ShareAccessContext $accessContext, string $id): Share;
+	public function getShare(string $id): Share;
 
 	/**
-	 * Get multiple shares.
+	 * Get a share by it's legacy provider and id.
+	 *
+	 * @throws ShareNotFoundException
+	 */
+	public function getShareByLegacyProviderAndId(string $legacyProvider, string $legacyId): Share;
+
+	/**
+	 * Get unmapped shares.
 	 *
-	 * @param ?class-string<IShareSourceType> $filterSourceTypeClass
-	 * @param ?positive-int $limit
 	 * @return list<Share>
 	 */
-	public function getShares(ShareAccessContext $accessContext, ?string $filterSourceTypeClass, ?string $filterSourceTypeValue, ?string $lastShareID, ?int $limit): array;
+	public function getUnmappedShares(IUser $user): array;
 }
diff --git a/lib/private/Sharing/SharingBackend.php b/lib/private/Sharing/SharingBackend.php
index 5d6cb5d4017d2..d6c4b0f473240 100644
--- a/lib/private/Sharing/SharingBackend.php
+++ b/lib/private/Sharing/SharingBackend.php
@@ -58,7 +58,7 @@ public function __construct(
 	}
 
 	#[\Override]
-	public function createShare(string $id, ShareUser $owner, int $lastUpdated): void {
+	public function createShare(string $id, ShareUser $owner, \DateTimeImmutable $lastUpdated): void {
 		$qb = $this->connection->getQueryBuilder();
 		$qb
 			->insert('sharing_share')
@@ -66,7 +66,7 @@ public function createShare(string $id, ShareUser $owner, int $lastUpdated): voi
 				'id' => $qb->createNamedParameter($id),
 				'owner_user_id' => $qb->createNamedParameter($owner->userId),
 				'owner_instance' => $qb->createNamedParameter($owner->instance),
-				'last_updated' => $qb->createNamedParameter($lastUpdated),
+				'last_updated' => $qb->createNamedParameter(SharingManager::timeToMs($lastUpdated)),
 				'state' => $qb->createNamedParameter(ShareState::Draft->value),
 			])
 			->executeStatement();
@@ -533,13 +533,13 @@ public function getShareOwner(string $id): ShareUser {
 	 * @param non-empty-list<string> $ids
 	 */
 	#[\Override]
-	public function setLastUpdated(array $ids, int $lastUpdated): void {
+	public function setLastUpdated(array $ids, \DateTimeImmutable $lastUpdated): void {
 		foreach (array_chunk($ids, 1000) as $chunk) {
 			$qb = $this->connection->getQueryBuilder();
 
 			$rowCount = $qb
 				->update('sharing_share')
-				->set('last_updated', $qb->createNamedParameter($lastUpdated, IQueryBuilder::PARAM_INT))
+				->set('last_updated', $qb->createNamedParameter(SharingManager::timeToMs($lastUpdated), IQueryBuilder::PARAM_INT))
 				->where($qb->expr()->in('id', $qb->createNamedParameter($chunk, IQueryBuilder::PARAM_INT_ARRAY)))
 				->executeStatement();
 			if ($rowCount !== count($chunk)) {
@@ -954,7 +954,7 @@ private function list(ShareAccessContext $accessContext, ?string $filterShareID,
 		$shares = array_map(static fn (array $share): Share => new Share(
 			$share['id'],
 			$share['owner'],
-			$share['last_updated'],
+			new \DateTimeImmutable('@' . $share['last_updated'] / 1000), // timestamp is stored in milliseconds
 			$share['state'],
 			$share['sources'],
 			$share['recipients'],
diff --git a/lib/private/Sharing/SharingManager.php b/lib/private/Sharing/SharingManager.php
index 76593a8f4bc0b..d42772d26b209 100644
--- a/lib/private/Sharing/SharingManager.php
+++ b/lib/private/Sharing/SharingManager.php
@@ -11,6 +11,7 @@
 
 use Exception;
 use NCU\Sharing\Exception\ShareInvalidException;
+use NCU\Sharing\Exception\ShareNotFoundException;
 use NCU\Sharing\Exception\ShareOperationForbiddenException;
 use NCU\Sharing\ISharingBackend;
 use NCU\Sharing\ISharingManager;
@@ -40,8 +41,16 @@
 use OCP\IUserManager;
 use OCP\L10N\IFactory;
 use OCP\Security\ISecureRandom;
+use OCP\Share\Events\AfterShareModifiedEvent;
+use OCP\Share\Events\ShareAcceptedEvent;
+use OCP\Share\Events\ShareCreatedEvent;
+use OCP\Share\Events\ShareDeletedEvent;
+use OCP\Share\Events\ShareDeletedFromSelfEvent;
+use OCP\Share\Events\ShareMovedEvent;
+use OCP\Share\IManager;
 use OCP\Snowflake\ISnowflakeGenerator;
 use OCP\User\Events\BeforeUserDeletedEvent;
+use Psr\Clock\ClockInterface;
 use Random\Randomizer;
 use RuntimeException;
 
@@ -53,22 +62,27 @@
 
 /**
  * @psalm-import-type SharingShare from Share
- * @template-implements IEventListener<BeforeUserDeletedEvent>
+ * @template-implements IEventListener<BeforeUserDeletedEvent|AfterShareModifiedEvent|ShareAcceptedEvent|ShareCreatedEvent|ShareDeletedEvent|ShareDeletedFromSelfEvent|ShareMovedEvent>
  */
-final readonly class SharingManager implements ISharingManager, IEventListener {
-	private Randomizer $randomizer;
+final class SharingManager implements ISharingManager, IEventListener {
+	private readonly Randomizer $randomizer;
 
-	private IL10N $l10n;
+	private readonly IL10N $l10n;
 
-	private ISharingBackend $backend;
+	private readonly ISharingBackend $backend;
+
+	/** @var array<string, true> */
+	private array $currentlyUpdatingLegacyShares;
 
 	public function __construct(
 		IEventDispatcher $eventDispatcher,
-		private IUserManager $userManager,
-		private IFactory $l10nFactory,
-		private ISnowflakeGenerator $snowflakeGenerator,
-		private IDBConnection $dbConnection,
-		private ISharingRegistry $registry,
+		private readonly IUserManager $userManager,
+		private readonly IFactory $l10nFactory,
+		private readonly ISnowflakeGenerator $snowflakeGenerator,
+		private readonly IDBConnection $dbConnection,
+		private readonly ISharingRegistry $registry,
+		private readonly IManager $legacyManager,
+		private readonly ClockInterface $clock,
 		IAppConfig $appConfig,
 	) {
 		$this->randomizer = new Randomizer();
@@ -83,6 +97,14 @@ public function __construct(
 		);
 
 		$eventDispatcher->addServiceListener(BeforeUserDeletedEvent::class, self::class);
+		$eventDispatcher->addServiceListener(AfterShareModifiedEvent::class, self::class);
+		$eventDispatcher->addServiceListener(ShareAcceptedEvent::class, self::class);
+		$eventDispatcher->addServiceListener(ShareCreatedEvent::class, self::class);
+		$eventDispatcher->addServiceListener(ShareDeletedEvent::class, self::class);
+		$eventDispatcher->addServiceListener(ShareDeletedFromSelfEvent::class, self::class);
+		$eventDispatcher->addServiceListener(ShareMovedEvent::class, self::class);
+
+		$this->currentlyUpdatingLegacyShares = [];
 	}
 
 	#[\Override]
@@ -140,13 +162,8 @@ public function generateSecret(): string {
 	}
 
 	#[\Override]
-	public function generateTimestamp(): int {
-		$time = (int)(microtime(true) * 1000.0);
-		if ($time < 0) {
-			throw new RuntimeException('Have you invented time travel?');
-		}
-
-		return $time;
+	public function getTime(): \DateTimeImmutable {
+		return $this->clock->now();
 	}
 
 	#[\Override]
@@ -158,7 +175,7 @@ public function createShare(ShareAccessContext $accessContext): string {
 		$this->assertInTransaction();
 
 		$id = $this->snowflakeGenerator->nextId();
-		$lastUpdated = $this->generateTimestamp();
+		$lastUpdated = $this->getTime();
 		$this->backend->createShare($id, new ShareUser($currentUser->getUID(), null), $lastUpdated);
 
 		$this->processShareUpdates([$id]);
@@ -190,7 +207,7 @@ public function onOwnerDeleted(ShareAccessContext $accessContext, ShareUser $own
 	public function updateShareState(ShareAccessContext $accessContext, string $id, ShareState $state): void {
 		$this->assertInTransaction();
 
-		$this->backend->setLastUpdated([$id], $this->generateTimestamp());
+		$this->backend->setLastUpdated([$id], $this->getTime());
 
 		$owner = $this->backend->getShareOwner($id);
 		$this->validateShareOwnerOperation($accessContext, $owner);
@@ -209,7 +226,7 @@ public function updateShareState(ShareAccessContext $accessContext, string $id,
 	public function addShareSource(ShareAccessContext $accessContext, string $id, ShareSource $source): void {
 		$this->assertInTransaction();
 
-		$this->backend->setLastUpdated([$id], $this->generateTimestamp());
+		$this->backend->setLastUpdated([$id], $this->getTime());
 
 		$owner = $this->backend->getShareOwner($id);
 		$this->validateShareOwnerOperation($accessContext, $owner);
@@ -250,7 +267,7 @@ public function addShareSource(ShareAccessContext $accessContext, string $id, Sh
 	public function removeShareSource(ShareAccessContext $accessContext, string $id, ShareSource $source): void {
 		$this->assertInTransaction();
 
-		$this->backend->setLastUpdated([$id], $this->generateTimestamp());
+		$this->backend->setLastUpdated([$id], $this->getTime());
 
 		$owner = $this->backend->getShareOwner($id);
 		$this->validateShareOwnerOperation($accessContext, $owner);
@@ -268,7 +285,7 @@ public function onSourceDeleted(ShareAccessContext $accessContext, ShareSource $
 
 		$this->assertInTransaction();
 
-		$timestamp = $this->generateTimestamp();
+		$timestamp = $this->getTime();
 
 		$updatedIds = $this->backend->onSourceDeleted($source);
 		if ($updatedIds === []) {
@@ -288,7 +305,7 @@ public function addShareRecipient(ShareAccessContext $accessContext, string $id,
 
 		$this->assertInTransaction();
 
-		$this->backend->setLastUpdated([$id], $this->generateTimestamp());
+		$this->backend->setLastUpdated([$id], $this->getTime());
 
 		$owner = $this->backend->getShareOwner($id);
 
@@ -351,7 +368,7 @@ public function removeShareRecipient(ShareAccessContext $accessContext, string $
 
 		$this->assertInTransaction();
 
-		$this->backend->setLastUpdated([$id], $this->generateTimestamp());
+		$this->backend->setLastUpdated([$id], $this->getTime());
 
 		$owner = $this->backend->getShareOwner($id);
 
@@ -376,7 +393,7 @@ public function onRecipientDeleted(ShareAccessContext $accessContext, ShareRecip
 
 		$this->assertInTransaction();
 
-		$timestamp = $this->generateTimestamp();
+		$timestamp = $this->getTime();
 
 		$updatedIds = $this->backend->onRecipientDeleted($recipient);
 		if ($updatedIds === []) {
@@ -396,7 +413,7 @@ public function onInitiatorDeleted(ShareAccessContext $accessContext, ShareUser
 
 		$this->assertInTransaction();
 
-		$timestamp = $this->generateTimestamp();
+		$timestamp = $this->getTime();
 
 		$updatedIds = $this->backend->onInitiatorDeleted($initiator);
 		if ($updatedIds === []) {
@@ -412,7 +429,7 @@ public function onInitiatorDeleted(ShareAccessContext $accessContext, ShareUser
 	public function updateShareRecipientSecret(ShareAccessContext $accessContext, string $id, ShareRecipient $recipient, string $secret): void {
 		$this->assertInTransaction();
 
-		$this->backend->setLastUpdated([$id], $this->generateTimestamp());
+		$this->backend->setLastUpdated([$id], $this->getTime());
 
 		$owner = $this->backend->getShareOwner($id);
 
@@ -444,7 +461,7 @@ public function updateShareRecipientSecret(ShareAccessContext $accessContext, st
 	public function createSharePropertyDefaultValue(Share $share, string $propertyTypeClass): Share {
 		$this->assertInTransaction();
 
-		$timestamp = $this->generateTimestamp();
+		$timestamp = $this->getTime();
 		$this->backend->setLastUpdated([$share->id], $timestamp);
 
 		if (($propertyType = $this->registry->getPropertyTypes()[$propertyTypeClass] ?? null) === null) {
@@ -478,7 +495,7 @@ public function createSharePropertyDefaultValue(Share $share, string $propertyTy
 	public function updateShareProperty(ShareAccessContext $accessContext, string $id, ShareProperty $property): void {
 		$this->assertInTransaction();
 
-		$this->backend->setLastUpdated([$id], $this->generateTimestamp());
+		$this->backend->setLastUpdated([$id], $this->getTime());
 
 		$owner = $this->backend->getShareOwner($id);
 		$this->validateShareOwnerOperation($accessContext, $owner);
@@ -503,8 +520,8 @@ public function updateShareProperty(ShareAccessContext $accessContext, string $i
 	public function createSharePermissionDefaultValue(Share $share, string $permissionTypeClass): Share {
 		$this->assertInTransaction();
 
-		$timestamp = $this->generateTimestamp();
-		$this->backend->setLastUpdated([$share->id], $timestamp);
+		$time = $this->getTime();
+		$this->backend->setLastUpdated([$share->id], $time);
 
 		if (($permissionType = $this->registry->getPermissionTypes()[$permissionTypeClass] ?? null) === null) {
 			throw new RuntimeException('The permission is not registered: ' . $permissionTypeClass);
@@ -520,7 +537,7 @@ public function createSharePermissionDefaultValue(Share $share, string $permissi
 		$share = new Share(
 			$share->id,
 			$share->owner,
-			$timestamp,
+			$time,
 			$share->state,
 			$share->sources,
 			$share->recipients,
@@ -537,7 +554,7 @@ public function createSharePermissionDefaultValue(Share $share, string $permissi
 	public function updateSharePermission(ShareAccessContext $accessContext, string $id, SharePermission $permission): void {
 		$this->assertInTransaction();
 
-		$this->backend->setLastUpdated([$id], $this->generateTimestamp());
+		$this->backend->setLastUpdated([$id], $this->getTime());
 
 		$owner = $this->backend->getShareOwner($id);
 		$this->validateShareOwnerOperation($accessContext, $owner);
@@ -574,7 +591,7 @@ public function updateSharePermission(ShareAccessContext $accessContext, string
 	public function selectSharePermissionPreset(ShareAccessContext $accessContext, string $id, string $permissionPresetClass): void {
 		$this->assertInTransaction();
 
-		$this->backend->setLastUpdated([$id], $this->generateTimestamp());
+		$this->backend->setLastUpdated([$id], $this->getTime());
 
 		$owner = $this->backend->getShareOwner($id);
 		$this->validateShareOwnerOperation($accessContext, $owner);
@@ -617,22 +634,124 @@ public function getShare(ShareAccessContext $accessContext, string $id): Share {
 	public function getShares(ShareAccessContext $accessContext, ?string $filterSourceTypeClass, ?string $filterSourceTypeValue, ?string $lastShareID, ?int $limit): array {
 		$this->assertInTransaction();
 
+		if (($currentUser = $accessContext->currentUser) instanceof IUser) {
+			$this->importSharesFromLegacyBackend($currentUser);
+		}
+
 		return $this->backend->getShares($accessContext, $filterSourceTypeClass, $filterSourceTypeValue, $lastShareID, $limit);
 	}
 
+	#[\Override]
+	public function importSharesFromLegacyBackend(IUser $user): array {
+		$this->assertInTransaction();
+
+		$shareIds = [];
+
+		$legacyBackend = $this->registry->getLegacyBackend();
+		if ($legacyBackend instanceof ISharingLegacyBackend) {
+			foreach ($legacyBackend->getUnmappedShares($user) as $unmappedShare) {
+				$this->updateShare($unmappedShare);
+				$shareIds[] = $unmappedShare->id;
+			}
+		}
+
+		return $shareIds;
+	}
+
+	#[\Override]
+	public function exportShareToLegacyBackend(string $id): void {
+		$this->assertInTransaction();
+
+		$share = $this->getShare(new ShareAccessContext(overrideChecks: true), $id);
+
+		$this->updateShareInLegacyBackend($share);
+	}
+
 	#[\Override]
 	public function handle(Event $event): void {
-		$shareUser = new ShareUser($event->getUser()->getUID(), null);
+		if ($event instanceof BeforeUserDeletedEvent) {
+			$shareUser = new ShareUser($event->getUser()->getUID(), null);
+
+			try {
+				$this->dbConnection->beginTransaction();
+				$this->onOwnerDeleted(new ShareAccessContext(overrideChecks: true), $shareUser);
+				$this->onInitiatorDeleted(new ShareAccessContext(overrideChecks: true), $shareUser);
+				$this->dbConnection->commit();
+			} catch (Exception $exception) {
+				$this->dbConnection->rollBack();
+				throw $exception;
+			}
+
+			return;
+		}
+
+		$legacyShare = $event->getShare();
+		$legacyBackend = $this->registry->getLegacyBackend();
+		if (!$legacyBackend instanceof ISharingLegacyBackend) {
+			return;
+		}
 
+		$ids = [];
 		try {
 			$this->dbConnection->beginTransaction();
-			$this->onOwnerDeleted(new ShareAccessContext(overrideChecks: true), $shareUser);
-			$this->onInitiatorDeleted(new ShareAccessContext(overrideChecks: true), $shareUser);
+			try {
+				$share = $legacyBackend->getShareByLegacyProviderAndId($legacyShare->getProviderId(), $legacyShare->getId());
+				if (!isset($this->currentlyUpdatingLegacyShares[$share->id])) {
+					$this->updateShare($share);
+					$ids[] = $share->id;
+				}
+			} catch (ShareNotFoundException) {
+				// TODO: Support federation
+				$owner = $this->userManager->get($legacyShare->getShareOwner());
+				if ($owner instanceof IUser) {
+					$ids = array_merge($ids, $this->importSharesFromLegacyBackend($owner));
+				}
+			}
+
 			$this->dbConnection->commit();
 		} catch (Exception $exception) {
 			$this->dbConnection->rollBack();
 			throw $exception;
 		}
+
+		// TODO: Only run in behat tests
+		return;
+		foreach ($ids as $id) {
+			try {
+				$this->dbConnection->beginTransaction();
+
+				$legacyIds = $legacyBackend->getLegacyFullIds($id);
+				$legacySharesBefore = array_map(fn (string $legacyId): IShare => $this->legacyManager->getShareById($legacyId), $legacyIds);
+
+				$this->exportShareToLegacyBackend($id);
+
+				$legacySharesAfter = array_map(fn (string $legacyId): IShare => $this->legacyManager->getShareById($legacyId), $legacyIds);
+
+				for ($i = 0, $iMax = count($legacyIds); $i < $iMax; ++$i) {
+					$legacyShareBefore = $legacySharesBefore[$i];
+					$legacyShareAfter = $legacySharesAfter[$i];
+
+					$comparisons = [
+						'id' => static fn (IShare $share): mixed => $share->getId(),
+						'full_id' => static fn (IShare $share): mixed => $share->getFullId(),
+						// TODO
+					];
+
+					foreach ($comparisons as $field => $getter) {
+						$valueBefore = $getter($legacyShareBefore);
+						$valueAfter = $getter($legacyShareAfter);
+						if ($valueBefore !== $valueAfter) {
+							throw new RuntimeException('Values for ' . $field . ' do not match:\\nBefore: ' . var_export($valueBefore, true) . '\\nAfter: ' . var_export($valueAfter, true));
+						}
+					}
+				}
+
+				$this->dbConnection->rollBack();
+			} catch (Exception $exception) {
+				$this->dbConnection->rollBack();
+				throw $exception;
+			}
+		}
 	}
 
 	private function assertInTransaction(): void {
@@ -802,28 +921,69 @@ private function processShareUpdates(array $sharesOrIds): array {
 				}
 			}
 
-			$legacyBackend = $this->registry->getLegacyBackend();
-			if ($legacyBackend instanceof ISharingLegacyBackend) {
-				$compatibleSourceTypes = array_fill_keys($legacyBackend->getCompatibleSourceTypes(), true);
-				foreach ($share->sources as $source) {
-					if (!isset($compatibleSourceTypes[$source->class])) {
-						throw new RuntimeException('The legacy backend ' . $legacyBackend::class . ' does not support this source type: ' . $source->class);
-					}
-				}
+			$this->currentlyUpdatingLegacyShares[$share->id] = true;
+			$this->updateShareInLegacyBackend($share);
+			unset($this->currentlyUpdatingLegacyShares[$share->id]);
 
-				$compatibleRecipientTypes = array_fill_keys($legacyBackend->getCompatibleRecipientTypes(), true);
-				foreach ($share->recipients as $recipient) {
-					if (!isset($compatibleRecipientTypes[$recipient->class])) {
-						throw new RuntimeException('The legacy backend ' . $legacyBackend::class . ' does not support this recipient type: ' . $recipient->class);
-					}
+			$shares[] = $share;
+		}
+
+		return $shares;
+	}
+
+	private function updateShareInLegacyBackend(Share $share): void {
+		$legacyBackend = $this->registry->getLegacyBackend();
+		if ($legacyBackend instanceof ISharingLegacyBackend) {
+			$compatibleSourceTypes = array_fill_keys($legacyBackend->getCompatibleSourceTypes(), true);
+			foreach ($share->sources as $source) {
+				if (!isset($compatibleSourceTypes[$source->class])) {
+					throw new RuntimeException('The legacy backend ' . $legacyBackend::class . ' does not support this source type: ' . $source->class);
 				}
+			}
 
-				$legacyBackend->updateShare($share);
+			$compatibleRecipientTypes = array_fill_keys($legacyBackend->getCompatibleRecipientTypes(), true);
+			foreach ($share->recipients as $recipient) {
+				if (!isset($compatibleRecipientTypes[$recipient->class])) {
+					throw new RuntimeException('The legacy backend ' . $legacyBackend::class . ' does not support this recipient type: ' . $recipient->class);
+				}
 			}
 
-			$shares[] = $share;
+			$legacyBackend->updateShare($share);
 		}
+	}
 
-		return $shares;
+	private function updateShare(Share $share): void {
+		// To avoid diffing the shares, we just delete and create it.
+		try {
+			$this->backend->deleteShare($share->id);
+		} catch (ShareNotFoundException) {
+		}
+
+		$this->backend->createShare($share->id, $share->owner, $share->lastUpdated);
+		$this->backend->updateShareState($share->id, $share->state);
+		foreach ($share->sources as $source) {
+			$this->backend->addShareSource($share->id, $source);
+		}
+
+		foreach ($share->recipients as $recipient) {
+			$this->backend->addShareRecipient($share->id, $recipient);
+		}
+
+		foreach ($share->properties as $property) {
+			$this->backend->createShareProperty($share->id, $property);
+		}
+
+		foreach ($share->permissions as $permission) {
+			$this->backend->createSharePermission($share->id, $permission);
+		}
+	}
+
+	public static function timeToMs(\DateTimeImmutable $time): int {
+		if (method_exists($time, 'getMicrosecond')) {
+			$micros = $time->getMicrosecond();
+		} else {
+			$micros = (int)$time->format('u');
+		}
+		return $time->getTimestamp() * 1000 + (int)floor($micros / 1000);
 	}
 }
diff --git a/lib/public/Share/Events/AfterShareModifiedEvent.php b/lib/public/Share/Events/AfterShareModifiedEvent.php
new file mode 100644
index 0000000000000..df9aa24f38611
--- /dev/null
+++ b/lib/public/Share/Events/AfterShareModifiedEvent.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\Share\Events;
+
+use OCP\AppFramework\Attribute\Consumable;
+use OCP\EventDispatcher\Event;
+use OCP\Share\IShare;
+
+/**
+ * @since 35.0.0
+ */
+// TODO: Create separate events and listen for each
+#[Consumable(since: '35.0.0')]
+final class AfterShareModifiedEvent extends Event {
+	/**
+	 * @since 35.0.0
+	 */
+	public function __construct(
+		public readonly IShare $share,
+	) {
+		parent::__construct();
+	}
+
+	/**
+	 * @since 35.0.0
+	 */
+	public function getShare(): IShare {
+		return $this->share;
+	}
+}
diff --git a/lib/public/Share/IShare.php b/lib/public/Share/IShare.php
index 5e5647f52aa10..8310bb5862040 100644
--- a/lib/public/Share/IShare.php
+++ b/lib/public/Share/IShare.php
@@ -155,6 +155,13 @@ public function getFullId(): string;
 	 */
 	public function setProviderId(string $id): self;
 
+	/**
+	 * Get the provider id.
+	 *
+	 * @since 35.0.0
+	 */
+	public function getProviderId(): string;
+
 	/**
 	 * Set the node of the file/folder that is shared
 	 *
diff --git a/lib/unstable/Sharing/ISharingBackend.php b/lib/unstable/Sharing/ISharingBackend.php
index a4cb1401dd9cc..5fbc5a7149abd 100644
--- a/lib/unstable/Sharing/ISharingBackend.php
+++ b/lib/unstable/Sharing/ISharingBackend.php
@@ -29,7 +29,7 @@ interface ISharingBackend {
 	 *
 	 * @experimental 35.0.0
 	 */
-	public function createShare(string $id, ShareUser $owner, int $lastUpdated): void;
+	public function createShare(string $id, ShareUser $owner, \DateTimeImmutable $lastUpdated): void;
 
 	/**
 	 * Perform all updates when the owner was deleted.
@@ -199,9 +199,8 @@ public function getShareOwner(string $id): ShareUser;
 	 * Set the last updated timestamp for multiple shares.
 	 *
 	 * @param non-empty-list<string> $ids
-	 * @param non-negative-int $lastUpdated
 	 * @throws ShareNotFoundException
 	 * @experimental 35.0.0
 	 */
-	public function setLastUpdated(array $ids, int $lastUpdated): void;
+	public function setLastUpdated(array $ids, \DateTimeImmutable $lastUpdated): void;
 }
diff --git a/lib/unstable/Sharing/ISharingManager.php b/lib/unstable/Sharing/ISharingManager.php
index 21128680aaefc..46965673904f1 100644
--- a/lib/unstable/Sharing/ISharingManager.php
+++ b/lib/unstable/Sharing/ISharingManager.php
@@ -22,6 +22,7 @@
 use NCU\Sharing\Source\IShareSourceType;
 use NCU\Sharing\Source\ShareSource;
 use OCP\AppFramework\Attribute\Consumable;
+use OCP\IUser;
 
 /**
  * @experimental 35.0.0
@@ -50,12 +51,11 @@ public function searchRecipients(ShareAccessContext $accessContext, ?array $filt
 	public function generateSecret(): string;
 
 	/**
-	 * Generate a new timestamp in milliseconds since the UNIX epoch.
-	 *
-	 * @return non-negative-int
+	 * Get the current time
+     *
 	 * @experimental 35.0.0
 	 */
-	public function generateTimestamp(): int;
+	public function getTime(): \DateTimeImmutable;
 
 	/**
 	 * Create a new share.
@@ -221,4 +221,15 @@ public function getShare(ShareAccessContext $accessContext, string $id): Share;
 	 * @experimental 35.0.0
 	 */
 	public function getShares(ShareAccessContext $accessContext, ?string $filterSourceTypeClass, ?string $filterSourceTypeValue, ?string $lastShareID, ?int $limit): array;
+
+	/**
+	 * @return list<string>
+	 * @since 35.0.0
+	 */
+	public function importSharesFromLegacyBackend(IUser $user): array;
+
+	/**
+	 * @since 35.0.0
+	 */
+	public function exportShareToLegacyBackend(string $id): void;
 }
diff --git a/lib/unstable/Sharing/Share.php b/lib/unstable/Sharing/Share.php
index ed74a4f2bcb8f..7f8f0cf01a7a9 100644
--- a/lib/unstable/Sharing/Share.php
+++ b/lib/unstable/Sharing/Share.php
@@ -154,8 +154,7 @@ public function __construct(
 		/** @var non-empty-string $id */
 		public readonly string $id,
 		public readonly ShareUser $owner,
-		/** @var non-negative-int $lastUpdated Unix time in milliseconds */
-		public readonly int $lastUpdated,
+		public readonly \DateTimeImmutable $lastUpdated,
 		public readonly ShareState $state,
 		/** @var list<ShareSource> $sources */
 		public readonly array $sources,
@@ -237,10 +236,12 @@ public function format(ISharingRegistry $registry, IFactory $l10nFactory, IURLGe
 		// First sort by priority and then sort by class name to get a stable order regardless of the DB order
 		usort($permissions, static fn (array $a, array $b): int => 2 * ($b['priority'] <=> $a['priority']) + ($a['class'] <=> $b['class']));
 
+		/** @var non-negative-int $timestamp */
+		$timestamp = $this->lastUpdated->getTimestamp();
 		return [
 			'id' => $this->id,
 			'owner' => $this->owner->format($userManager),
-			'last_updated' => $this->lastUpdated,
+			'last_updated' => $timestamp,
 			'state' => $this->state->value,
 			'sources' => ShareSource::formatMultiple($registry, $l10nFactory, $this->sources),
 			'recipients' => ShareRecipient::formatMultiple($registry, $l10nFactory, $urlGenerator, $userManager, $this->recipients),
diff --git a/psalm-strict.xml b/psalm-strict.xml
index c1b5dc95b0a22..fffa842517d16 100644
--- a/psalm-strict.xml
+++ b/psalm-strict.xml
@@ -53,6 +53,8 @@
 		<directory name="tests/Core/Sharing"/>
 		<directory name="apps/files/lib/Sharing"/>
 		<directory name="apps/files/tests/Sharing"/>
+		<directory name="apps/files_sharing/lib/Sharing"/>
+		<directory name="apps/files_sharing/tests/Sharing"/>
 		<ignoreFiles>
 			<!-- Circles internals are used -->
 			<file name="core/Sharing/Recipient/TeamShareRecipientType.php"/>
diff --git a/tests/Core/Sharing/Recipient/GroupShareRecipientTypeTest.php b/tests/Core/Sharing/Recipient/GroupShareRecipientTypeTest.php
index abfd54bc2a847..9866137487205 100644
--- a/tests/Core/Sharing/Recipient/GroupShareRecipientTypeTest.php
+++ b/tests/Core/Sharing/Recipient/GroupShareRecipientTypeTest.php
@@ -15,6 +15,7 @@
 use NCU\Sharing\ShareAccessContext;
 use OC\Core\Sharing\Recipient\GroupShareRecipientType;
 use OC\Group\Database;
+use OC\Sharing\SharingManager;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\IDBConnection;
 use OCP\IGroup;
@@ -140,14 +141,14 @@ public function testDelete(): void {
 		$this->manager->addShareRecipient($accessContext, $id, new ShareRecipient($this->recipientType::class, $this->group1->getGID(), null));
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->group1->delete();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$this->dbConnection->beginTransaction();
 		$share = $this->manager->getShare($accessContext, $id);
-		$this->assertGreaterThanOrEqual($before, $share->lastUpdated);
-		$this->assertLessThanOrEqual($after, $share->lastUpdated);
+		$this->assertGreaterThanOrEqual($before, SharingManager::timeToMs($share->lastUpdated));
+		$this->assertLessThanOrEqual($after, SharingManager::timeToMs($share->lastUpdated));
 		$this->assertEquals([], $share->recipients);
 
 		$this->manager->deleteShare($accessContext, $id);
diff --git a/tests/Core/Sharing/Recipient/TeamShareRecipientTypeTest.php b/tests/Core/Sharing/Recipient/TeamShareRecipientTypeTest.php
index 8b24d567c1655..31bbfd3458a55 100644
--- a/tests/Core/Sharing/Recipient/TeamShareRecipientTypeTest.php
+++ b/tests/Core/Sharing/Recipient/TeamShareRecipientTypeTest.php
@@ -171,14 +171,14 @@ public function testDelete(): void {
 		$circlesManager = Server::get(CirclesManager::class);
 		$circlesManager->startSession($circlesManager->getLocalFederatedUser($this->user1->getUID()));
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$circlesManager->destroyCircle($this->team1->getId());
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$this->dbConnection->beginTransaction();
 		$share = $this->manager->getShare($accessContext, $id);
-		$this->assertGreaterThanOrEqual($before, $share->lastUpdated);
-		$this->assertLessThanOrEqual($after, $share->lastUpdated);
+		$this->assertGreaterThanOrEqual($before, $share->lastUpdated->getTimestamp());
+		$this->assertLessThanOrEqual($after, $share->lastUpdated->getTimestamp());
 		$this->assertEquals([], $share->recipients);
 
 		$this->manager->deleteShare($accessContext, $id);
diff --git a/tests/Core/Sharing/Recipient/UserShareRecipientTypeTest.php b/tests/Core/Sharing/Recipient/UserShareRecipientTypeTest.php
index 453c0ecd12ac4..49935cd13d980 100644
--- a/tests/Core/Sharing/Recipient/UserShareRecipientTypeTest.php
+++ b/tests/Core/Sharing/Recipient/UserShareRecipientTypeTest.php
@@ -14,6 +14,7 @@
 use NCU\Sharing\Recipient\ShareRecipient;
 use NCU\Sharing\ShareAccessContext;
 use OC\Core\Sharing\Recipient\UserShareRecipientType;
+use OC\Sharing\SharingManager;
 use OC\User\Database;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\IDBConnection;
@@ -144,14 +145,14 @@ public function testDelete(): void {
 		$this->manager->addShareRecipient($accessContext, $id, new ShareRecipient($this->recipientType::class, $this->user2->getUID(), null));
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->user2->delete();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$this->dbConnection->beginTransaction();
 		$share = $this->manager->getShare($accessContext, $id);
-		$this->assertGreaterThanOrEqual($before, $share->lastUpdated);
-		$this->assertLessThanOrEqual($after, $share->lastUpdated);
+		$this->assertGreaterThanOrEqual($before, SharingManager::timeToMs($share->lastUpdated));
+		$this->assertLessThanOrEqual($after, SharingManager::timeToMs($share->lastUpdated));
 		$this->assertEquals([], $share->recipients);
 
 		$this->manager->deleteShare($accessContext, $id);
diff --git a/tests/lib/Sharing/AbstractSharingManagerTests.php b/tests/lib/Sharing/AbstractSharingManagerTests.php
index 8f4522dc86ff2..5da9fe2777908 100644
--- a/tests/lib/Sharing/AbstractSharingManagerTests.php
+++ b/tests/lib/Sharing/AbstractSharingManagerTests.php
@@ -567,9 +567,9 @@ public function testSearchRecipientsOmitExisting(): void {
 	public function testCreateShare(): void {
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->createShare($accessContext);
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		unset($share['id']);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
@@ -690,9 +690,9 @@ public function testUpdateShareState(array $sources, array $recipients, array $p
 				$this->assertEquals($errorMessage, $exception->getHint());
 			}
 		} else {
-			$before = $this->manager->generateTimestamp();
+			$before = $this->manager->getTime();
 			$share = $this->updateShareState($accessContext, $id, ShareState::Active);
-			$after = $this->manager->generateTimestamp();
+			$after = $this->manager->getTime();
 			$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 			$this->assertLessThanOrEqual($after, $share['last_updated']);
 			$this->assertEquals(ShareState::Active->value, $share['state']);
@@ -706,9 +706,9 @@ public function testAddShareSource(): void {
 		$id = $this->manager->createShare($accessContext);
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals([
@@ -765,9 +765,9 @@ public function testRemoveShareSource(): void {
 
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->removeShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Active->value, $share['state']);
@@ -782,9 +782,9 @@ public function testRemoveShareSource(): void {
 			],
 		], $share['sources']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->removeShareSource($accessContext, $id, new ShareSource(TestShareSourceType2::class, 'source2'));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Draft->value, $share['state']);
@@ -798,9 +798,9 @@ public function testAddShareRecipient(): void {
 		$id = $this->manager->createShare($accessContext);
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->addShareRecipient($accessContext, $id, new ShareRecipient(TestShareRecipientType1::class, 'recipient1', null));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals([
@@ -890,9 +890,9 @@ public function testAddChildShareRecipientWithResharePermission(): void {
 
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->addShareRecipient(new ShareAccessContext($this->user1), $id, new ShareRecipient(TestShareRecipientType2::class, 'recipient2', null));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals([
@@ -955,9 +955,9 @@ public function testRemoveShareRecipient(): void {
 
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->removeShareRecipient($accessContext, $id, new ShareRecipient(TestShareRecipientType1::class, 'recipient1', null));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Active->value, $share['state']);
@@ -985,9 +985,9 @@ public function testRemoveShareRecipient(): void {
 			],
 		], $share['recipients']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->removeShareRecipient($accessContext, $id, new ShareRecipient(TestShareRecipientType2::class, 'recipient2', null));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Draft->value, $share['state']);
@@ -1074,9 +1074,9 @@ public function testRemoveChildShareRecipientWithResharePermission(): void {
 
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->removeShareRecipient(new ShareAccessContext($this->user1), $id, new ShareRecipient(TestShareRecipientType2::class, 'recipient2', null));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals([
@@ -1232,9 +1232,9 @@ public function testUpdateShareRecipientSecret(bool $isSecretUpdatable): void {
 				$this->assertEquals('You are not allowed to edit this share.', $exception->getHint());
 			}
 		} else {
-			$before = $this->manager->generateTimestamp();
+			$before = $this->manager->getTime();
 			$share = $this->updateShareRecipientSecret($accessContext, $id, $recipient, 'mysecret');
-			$after = $this->manager->generateTimestamp();
+			$after = $this->manager->getTime();
 			$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 			$this->assertLessThanOrEqual($after, $share['last_updated']);
 			unset($share['last_updated']);
@@ -1292,9 +1292,9 @@ public function testUpdateShareProperty(array $values): void {
 		$this->dbConnection->commit();
 
 		foreach ($values as $value) {
-			$before = $this->manager->generateTimestamp();
+			$before = $this->manager->getTime();
 			$share = $this->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyType1::class, $value));
-			$after = $this->manager->generateTimestamp();
+			$after = $this->manager->getTime();
 			$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 			$this->assertLessThanOrEqual($after, $share['last_updated']);
 			$this->assertEquals([
@@ -1329,9 +1329,9 @@ public function testUpdateSharePropertyRequired(): void {
 
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyTypeRequired::class, 'valid1'));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Draft->value, $share['state']);
@@ -1364,9 +1364,9 @@ public function testUpdateSharePropertyRequired(): void {
 		$this->manager->updateShareState($accessContext, $id, ShareState::Active);
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyTypeRequired::class, 'valid2'));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Active->value, $share['state']);
@@ -1395,9 +1395,9 @@ public function testUpdateSharePropertyRequired(): void {
 			],
 		], $share['properties']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyTypeRequired::class, null));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Draft->value, $share['state']);
@@ -1497,9 +1497,9 @@ public function testUpdateSharePropertyModifyProperties(): void {
 		$this->manager->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyTypeModifyValue::class, 'old-value'));
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyTypeModifyValue::class, 'modify-on-save-old-value'));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals([
@@ -1527,9 +1527,9 @@ public function testUpdateSharePropertyModifyProperties(): void {
 			],
 		], $share['properties']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyTypeModifyValue::class, 'modify-on-save'));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals([
@@ -1557,9 +1557,9 @@ public function testUpdateSharePropertyModifyProperties(): void {
 			],
 		], $share['properties']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyTypeModifyValue::class, 'modify-on-load'));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals([
@@ -1599,10 +1599,10 @@ public function testUpdateSharePermission(): void {
 
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->updateSharePermission($accessContext, $id, new SharePermission(ReshareSharePermissionType::class, true));
 		$share = $this->updateSharePermission($accessContext, $id, new SharePermission(TestSharePermissionType1::class, true));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Draft->value, $share['state']);
@@ -1631,9 +1631,9 @@ public function testUpdateSharePermission(): void {
 		$this->manager->updateShareState($accessContext, $id, ShareState::Active);
 		$this->dbConnection->commit();
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateSharePermission($accessContext, $id, new SharePermission(ReshareSharePermissionType::class, false));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Active->value, $share['state']);
@@ -1658,9 +1658,9 @@ public function testUpdateSharePermission(): void {
 			],
 		], $share['permissions']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateSharePermission($accessContext, $id, new SharePermission(TestSharePermissionType1::class, false));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(ShareState::Draft->value, $share['state']);
@@ -1727,12 +1727,12 @@ public function testSelectSharePermissionPreset(): void {
 
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->getShare($accessContext, $id);
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare($accessContext, $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -1768,9 +1768,9 @@ public function testSelectSharePermissionPreset(): void {
 			],
 		], $share['permissions']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->selectSharePermissionPreset($accessContext, $id, TestSharePermissionPreset2::class);
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(TestSharePermissionPreset2::class, $share['permission_preset']);
@@ -1804,9 +1804,9 @@ public function testSelectSharePermissionPreset(): void {
 			],
 		], $share['permissions']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateSharePermission($accessContext, $id, new SharePermission(TestSharePermissionType3::class, true));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertNull($share['permission_preset']);
@@ -1840,9 +1840,9 @@ public function testSelectSharePermissionPreset(): void {
 			],
 		], $share['permissions']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->selectSharePermissionPreset($accessContext, $id, TestSharePermissionPreset1::class);
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(TestSharePermissionPreset1::class, $share['permission_preset']);
@@ -1876,9 +1876,9 @@ public function testSelectSharePermissionPreset(): void {
 			],
 		], $share['permissions']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->updateSharePermission($accessContext, $id, new SharePermission(TestSharePermissionType1::class, false));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertNull($share['permission_preset']);
@@ -1926,12 +1926,12 @@ public function testSelectSharePermissionPresetCompatible(): void {
 
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->getShare($accessContext, $id);
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare($accessContext, $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -1949,9 +1949,9 @@ public function testSelectSharePermissionPresetCompatible(): void {
 			],
 		], $share['permissions']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->selectSharePermissionPreset($accessContext, $id, TestSharePermissionPreset2::class);
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(TestSharePermissionPreset2::class, $share['permission_preset']);
@@ -1967,9 +1967,9 @@ public function testSelectSharePermissionPresetCompatible(): void {
 			],
 		], $share['permissions']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertNull($share['permission_preset']);
@@ -1994,9 +1994,9 @@ public function testSelectSharePermissionPresetCompatible(): void {
 			],
 		], $share['permissions']);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$share = $this->selectSharePermissionPreset($accessContext, $id, TestSharePermissionPreset2::class);
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
 		$this->assertLessThanOrEqual($after, $share['last_updated']);
 		$this->assertEquals(TestSharePermissionPreset2::class, $share['permission_preset']);
@@ -2043,7 +2043,7 @@ public function testDeleteShare(): void {
 	public function testGetShare(): void {
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -2051,7 +2051,7 @@ public function testGetShare(): void {
 		$this->manager->getShare($accessContext, $id);
 
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare($accessContext, $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -2160,7 +2160,7 @@ public function testGetShareAsRecipientNotActive(): void {
 	public function testGetShareAsRecipientActive(): void {
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -2171,7 +2171,7 @@ public function testGetShareAsRecipientActive(): void {
 		$this->manager->updateShareState($accessContext, $id, ShareState::Active);
 
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare(new ShareAccessContext(currentUser: $this->user1), $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -2285,7 +2285,7 @@ public function testGetShareAsRecipientWithArguments(): void {
 
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -2295,7 +2295,7 @@ public function testGetShareAsRecipientWithArguments(): void {
 		$this->manager->updateShareState($accessContext, $id, ShareState::Active);
 
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare(new ShareAccessContext(currentUser: $this->user1, arguments: [TestShareRecipientTypeArguments::class => 'secret']), $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -2409,7 +2409,7 @@ public function testGetShareWithSecretActive(): void {
 
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -2418,7 +2418,7 @@ public function testGetShareWithSecretActive(): void {
 		$this->manager->updateSharePermission($accessContext, $id, new SharePermission(TestSharePermissionType1::class, true));
 		$this->manager->updateShareState($accessContext, $id, ShareState::Active);
 
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->manager->getShare($accessContext, $id);
 		$this->dbConnection->commit();
@@ -2535,7 +2535,7 @@ public function testGetShareAsRecipientFilteredProperties(): void {
 
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -2546,7 +2546,7 @@ public function testGetShareAsRecipientFilteredProperties(): void {
 		$this->manager->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyTypeFilter::class, 'visible'));
 
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare(new ShareAccessContext(currentUser: $this->user1), $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -2644,11 +2644,11 @@ public function testGetShareAsRecipientFilteredProperties(): void {
 			'permission_preset' => TestSharePermissionPreset1::class,
 		], $share);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$this->manager->updateShareProperty($accessContext, $id, new ShareProperty(TestSharePropertyTypeFilter::class, 'filtered'));
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare(new ShareAccessContext(currentUser: $this->owner), $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -2761,7 +2761,7 @@ public function testGetShareAsRecipientFilteredArguments(): void {
 
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -2771,7 +2771,7 @@ public function testGetShareAsRecipientFilteredArguments(): void {
 		$this->manager->updateShareState($accessContext, $id, ShareState::Active);
 
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare(new ShareAccessContext(currentUser: $this->user1), $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -3004,14 +3004,14 @@ public function testGetShareWithPublicSecret(bool $isSecretPublic): void {
 
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareRecipient($accessContext, $id, new ShareRecipient(TestShareRecipientType1::class, 'recipient1', null));
 		$this->manager->addShareRecipient($accessContext, $id, new ShareRecipient(TestShareRecipientTypePublicSecret::class, 'recipient2', null));
 
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare($accessContext, $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -3081,7 +3081,7 @@ public function testGetShareWithSecret(): void {
 
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -3094,7 +3094,7 @@ public function testGetShareWithSecret(): void {
 		$this->manager->addShareRecipient(new ShareAccessContext($this->user2), $id, new ShareRecipient(TestShareRecipientTypePublicSecret::class, 'recipient4', null));
 
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$share = $this->getShare(new ShareAccessContext($this->user2), $id);
 		$this->assertGreaterThanOrEqual($before, $share['last_updated']);
@@ -3255,7 +3255,7 @@ public function testGetShareUniqueDisplayNames(): void {
 	public function testGetShareDisabledOwner(): void {
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -3266,7 +3266,7 @@ public function testGetShareDisabledOwner(): void {
 		$this->manager->updateShareState($accessContext, $id, ShareState::Active);
 
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$this->owner->setEnabled(false);
 
@@ -3294,7 +3294,7 @@ public function testGetShareDisabledOwner(): void {
 	public function testGetShareDisabledInitiator(): void {
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -3304,7 +3304,7 @@ public function testGetShareDisabledInitiator(): void {
 		$this->manager->addShareRecipient(new ShareAccessContext(currentUser: $this->user1), $id, new ShareRecipient(TestShareRecipientType2::class, 'recipient2', null));
 
 		$this->dbConnection->commit();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 
 		$this->user1->setEnabled(false);
 
@@ -3367,7 +3367,7 @@ public function testGetShareDisabledInitiator(): void {
 	public function testGetShares(): void {
 		$accessContext = new ShareAccessContext($this->owner);
 
-		$before1 = $this->manager->generateTimestamp();
+		$before1 = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id1 = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id1, new ShareSource(TestShareSourceType1::class, 'source1'));
@@ -3375,9 +3375,9 @@ public function testGetShares(): void {
 		$this->manager->getShare($accessContext, $id1);
 
 		$this->dbConnection->commit();
-		$after1 = $this->manager->generateTimestamp();
+		$after1 = $this->manager->getTime();
 
-		$before2 = $this->manager->generateTimestamp();
+		$before2 = $this->manager->getTime();
 		$this->dbConnection->beginTransaction();
 		$id2 = $this->manager->createShare($accessContext);
 		$this->manager->addShareSource($accessContext, $id2, new ShareSource(TestShareSourceType2::class, 'source2'));
@@ -3385,7 +3385,7 @@ public function testGetShares(): void {
 		$this->manager->getShare($accessContext, $id2);
 
 		$this->dbConnection->commit();
-		$after2 = $this->manager->generateTimestamp();
+		$after2 = $this->manager->getTime();
 
 		$shares = $this->getShares($accessContext, null, null, null, null);
 		$this->assertCount(2, $shares);
@@ -3978,9 +3978,9 @@ public function testInitiatorDeleted(): void {
 		$this->manager->updateShareState($accessContext, $id, ShareState::Active);
 		$this->manager->addShareRecipient(new ShareAccessContext(currentUser: $this->user1), $id, new ShareRecipient(TestShareRecipientType2::class, 'recipient2', null));
 
-		$before = $this->manager->generateTimestamp();
+		$before = $this->manager->getTime();
 		$this->user1->delete();
-		$after = $this->manager->generateTimestamp();
+		$after = $this->manager->getTime();
 		$this->dbConnection->commit();
 
 		$share = $this->getShare(new ShareAccessContext(overrideChecks: true), $id);
diff --git a/unified-sharing-check.sh b/unified-sharing-check.sh
new file mode 100755
index 0000000000000..c1d5f50e70447
--- /dev/null
+++ b/unified-sharing-check.sh
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -euxo pipefail
+
+composer psalm
+composer psalm:ocp
+composer psalm:ncu
+composer psalm:strict
+composer rector:strict
+composer openapi
+./build/autoloaderchecker.sh
diff --git a/unified-sharing-test.sh b/unified-sharing-test.sh
new file mode 100755
index 0000000000000..2d965aa7088e4
--- /dev/null
+++ b/unified-sharing-test.sh
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+set -euxo pipefail
+
+for target in tests/lib/Sharing tests/Core/Sharing apps/sharing apps/files/tests/Sharing apps/files_sharing/tests/Listener/RestrictInteractionListenerTest.php apps/files_sharing/tests/Sharing; do
+	if [ -d "$target" ] || [ -f "$target" ]; then
+		./autotest.sh sqlite "$target"
+	fi
+done