diff --git a/lib/private/Calendar/Resource/Manager.php b/lib/private/Calendar/Resource/Manager.php
index cd00e20649d19..e5e0c93100c06 100644
--- a/lib/private/Calendar/Resource/Manager.php
+++ b/lib/private/Calendar/Resource/Manager.php
@@ -11,7 +11,6 @@
 
 use OC\AppFramework\Bootstrap\Coordinator;
 use OC\Calendar\ResourcesRoomsUpdater;
-use OCP\AppFramework\QueryException;
 use OCP\Calendar\Resource\IBackend;
 use OCP\Calendar\Resource\IManager;
 use Psr\Container\ContainerInterface;
@@ -21,11 +20,11 @@ class Manager implements IManager {
 
 	/**
 	 * @var string[] holds all registered resource backends
-	 * @psalm-var class-string<IBackend>[]
+	 * @psalm-var list<class-string<IBackend>>
 	 */
 	private array $backends = [];
 
-	/** @var IBackend[] holds all backends that have been initialized already */
+	/** @var array<class-string<IBackend>, IBackend> holds all backends that have been initialized already */
 	private array $initializedBackends = [];
 
 	public function __construct(
@@ -35,26 +34,6 @@ public function __construct(
 	) {
 	}
 
-	/**
-	 * Registers a resource backend
-	 *
-	 * @since 14.0.0
-	 */
-	#[\Override]
-	public function registerBackend(string $backendClass): void {
-		$this->backends[$backendClass] = $backendClass;
-	}
-
-	/**
-	 * Unregisters a resource backend
-	 *
-	 * @since 14.0.0
-	 */
-	#[\Override]
-	public function unregisterBackend(string $backendClass): void {
-		unset($this->backends[$backendClass], $this->initializedBackends[$backendClass]);
-	}
-
 	private function fetchBootstrapBackends(): void {
 		if ($this->bootstrapBackendsLoaded) {
 			return;
@@ -71,12 +50,6 @@ private function fetchBootstrapBackends(): void {
 		}
 	}
 
-	/**
-	 * @return IBackend[]
-	 * @throws QueryException
-	 * @since 14.0.0
-	 */
-	#[\Override]
 	public function getBackends():array {
 		$this->fetchBootstrapBackends();
 
@@ -91,12 +64,7 @@ public function getBackends():array {
 		return array_values($this->initializedBackends);
 	}
 
-	/**
-	 * @param string $backendId
-	 * @throws QueryException
-	 */
-	#[\Override]
-	public function getBackend($backendId): ?IBackend {
+	public function getBackend(string $backendId): ?IBackend {
 		$backends = $this->getBackends();
 		foreach ($backends as $backend) {
 			if ($backend->getBackendIdentifier() === $backendId) {
@@ -107,17 +75,6 @@ public function getBackend($backendId): ?IBackend {
 		return null;
 	}
 
-	/**
-	 * removes all registered backend instances
-	 *
-	 * @since 14.0.0
-	 */
-	#[\Override]
-	public function clear(): void {
-		$this->backends = [];
-		$this->initializedBackends = [];
-	}
-
 	#[\Override]
 	public function update(): void {
 		$this->updater->updateResources();
diff --git a/lib/private/Calendar/ResourcesRoomsUpdater.php b/lib/private/Calendar/ResourcesRoomsUpdater.php
index 10baad4a1f25b..3134655c6cc25 100644
--- a/lib/private/Calendar/ResourcesRoomsUpdater.php
+++ b/lib/private/Calendar/ResourcesRoomsUpdater.php
@@ -13,9 +13,7 @@
 use OCP\Calendar\BackendTemporarilyUnavailableException;
 use OCP\Calendar\IMetadataProvider;
 use OCP\Calendar\Resource\IBackend as IResourceBackend;
-use OCP\Calendar\Resource\IManager as IResourceManager;
 use OCP\Calendar\Resource\IResource;
-use OCP\Calendar\Room\IManager as IRoomManager;
 use OCP\Calendar\Room\IRoom;
 use OCP\IDBConnection;
 use Psr\Container\ContainerInterface;
@@ -33,7 +31,7 @@ public function __construct(
 	 */
 	public function updateResources(): void {
 		$this->updateFromBackend(
-			$this->container->get(IResourceManager::class),
+			$this->container->get(Resource\Manager::class),
 			'calendar_resources',
 			'calendar_resources_md',
 			'resource_id',
@@ -46,7 +44,7 @@ public function updateResources(): void {
 	 */
 	public function updateRooms(): void {
 		$this->updateFromBackend(
-			$this->container->get(IRoomManager::class),
+			$this->container->get(Room\Manager::class),
 			'calendar_rooms',
 			'calendar_rooms_md',
 			'room_id',
@@ -57,7 +55,7 @@ public function updateRooms(): void {
 	/**
 	 * Update cache from one specific backend manager, either ResourceManager or RoomManager
 	 *
-	 * @param IResourceManager|IRoomManager $backendManager
+	 * @param Resource\Manager|Room\Manager $backendManager
 	 */
 	private function updateFromBackend($backendManager,
 		string $dbTable,
@@ -311,15 +309,9 @@ private function serializeGroupRestrictions(array $groups): string {
 	/**
 	 * Gets all metadata of a backend
 	 *
-	 * @param IResource|IRoom $resource
-	 *
-	 * @return array
+	 * @return array<string, ?string>
 	 */
-	private function getAllMetadataOfBackend($resource): array {
-		if (!($resource instanceof IMetadataProvider)) {
-			return [];
-		}
-
+	private function getAllMetadataOfBackend(IMetadataProvider $resource): array {
 		$keys = $resource->getAllAvailableMetadataKeys();
 		$metadata = [];
 		foreach ($keys as $key) {
diff --git a/lib/private/Calendar/Room/Manager.php b/lib/private/Calendar/Room/Manager.php
index 76de5eb34a73c..4fbfe7450d03f 100644
--- a/lib/private/Calendar/Room/Manager.php
+++ b/lib/private/Calendar/Room/Manager.php
@@ -11,7 +11,6 @@
 
 use OC\AppFramework\Bootstrap\Coordinator;
 use OC\Calendar\ResourcesRoomsUpdater;
-use OCP\AppFramework\QueryException;
 use OCP\Calendar\Room\IBackend;
 use OCP\Calendar\Room\IManager;
 use Psr\Container\ContainerInterface;
@@ -35,27 +34,6 @@ public function __construct(
 	) {
 	}
 
-	/**
-	 * Registers a resource backend
-	 *
-	 * @since 14.0.0
-	 */
-	#[\Override]
-	public function registerBackend(string $backendClass): void {
-		$this->backends[$backendClass] = $backendClass;
-	}
-
-	/**
-	 * Unregisters a resource backend
-	 *
-	 * @param string $backendClass
-	 * @since 14.0.0
-	 */
-	#[\Override]
-	public function unregisterBackend(string $backendClass): void {
-		unset($this->backends[$backendClass], $this->initializedBackends[$backendClass]);
-	}
-
 	private function fetchBootstrapBackends(): void {
 		if ($this->bootstrapBackendsLoaded) {
 			return;
@@ -72,12 +50,6 @@ private function fetchBootstrapBackends(): void {
 		}
 	}
 
-	/**
-	 * @return IBackend[]
-	 * @throws QueryException
-	 * @since 14.0.0
-	 */
-	#[\Override]
 	public function getBackends():array {
 		$this->fetchBootstrapBackends();
 
@@ -89,7 +61,7 @@ public function getBackends():array {
 			/**
 			 * @todo fetch from the app container
 			 *
-			 * The backend might have services injected that can't be build from the
+			 * The backend might have services injected that can't be built from the
 			 * server container.
 			 */
 			$this->initializedBackends[$backend] = $this->container->get($backend);
@@ -98,12 +70,7 @@ public function getBackends():array {
 		return array_values($this->initializedBackends);
 	}
 
-	/**
-	 * @param string $backendId
-	 * @throws QueryException
-	 */
-	#[\Override]
-	public function getBackend($backendId): ?IBackend {
+	public function getBackend(string $backendId): ?IBackend {
 		$backends = $this->getBackends();
 		foreach ($backends as $backend) {
 			if ($backend->getBackendIdentifier() === $backendId) {
@@ -114,17 +81,6 @@ public function getBackend($backendId): ?IBackend {
 		return null;
 	}
 
-	/**
-	 * removes all registered backend instances
-	 *
-	 * @since 14.0.0
-	 */
-	#[\Override]
-	public function clear(): void {
-		$this->backends = [];
-		$this->initializedBackends = [];
-	}
-
 	#[\Override]
 	public function update(): void {
 		$this->updater->updateRooms();
diff --git a/lib/public/Calendar/Resource/IManager.php b/lib/public/Calendar/Resource/IManager.php
index 6bc0c9e82f9f3..d8a8c8ed4c0a6 100644
--- a/lib/public/Calendar/Resource/IManager.php
+++ b/lib/public/Calendar/Resource/IManager.php
@@ -13,49 +13,6 @@
  * @since 14.0.0
  */
 interface IManager {
-	/**
-	 * Registers a resource backend
-	 *
-	 * @param string $backendClass
-	 * @return void
-	 * @since 14.0.0
-	 * @deprecated 24.0.0 use \OCP\AppFramework\Bootstrap\IRegistrationContext::registerCalendarResourceBackend
-	 */
-	public function registerBackend(string $backendClass);
-
-	/**
-	 * Unregisters a resource backend
-	 *
-	 * @param string $backendClass
-	 * @return void
-	 * @since 14.0.0
-	 * @deprecated 24.0.0
-	 */
-	public function unregisterBackend(string $backendClass);
-
-	/**
-	 * @return IBackend[]
-	 * @since 14.0.0
-	 * @deprecated 24.0.0
-	 */
-	public function getBackends():array;
-
-	/**
-	 * @param string $backendId
-	 * @return IBackend|null
-	 * @since 14.0.0
-	 * @deprecated 24.0.0
-	 */
-	public function getBackend($backendId);
-
-	/**
-	 * removes all registered backend instances
-	 * @return void
-	 * @since 14.0.0
-	 * @deprecated 24.0.0
-	 */
-	public function clear();
-
 	/**
 	 * Update all resources from all backends right now.
 	 *
diff --git a/lib/public/Calendar/Room/IBackend.php b/lib/public/Calendar/Room/IBackend.php
index 34dfbf77f729b..17b71862d7f10 100644
--- a/lib/public/Calendar/Room/IBackend.php
+++ b/lib/public/Calendar/Room/IBackend.php
@@ -16,7 +16,7 @@
  */
 interface IBackend {
 	/**
-	 * get a list of all rooms in this backend
+	 * Get a list of all rooms in this backend.
 	 *
 	 * @throws BackendTemporarilyUnavailableException
 	 * @return IRoom[]
@@ -25,7 +25,7 @@ interface IBackend {
 	public function getAllRooms():array;
 
 	/**
-	 * get a list of all room identifiers in this backend
+	 * Get a list of all room identifiers in this backend.
 	 *
 	 * @throws BackendTemporarilyUnavailableException
 	 * @return string[]
@@ -34,7 +34,7 @@ public function getAllRooms():array;
 	public function listAllRooms():array;
 
 	/**
-	 * get a room by it's id
+	 * Get a room by its id.
 	 *
 	 * @param string $id
 	 * @throws BackendTemporarilyUnavailableException
@@ -44,7 +44,7 @@ public function listAllRooms():array;
 	public function getRoom($id);
 
 	/**
-	 * Get unique identifier of the backend
+	 * Get unique identifier of the backend.
 	 *
 	 * @return string
 	 * @since 14.0.0
diff --git a/lib/public/Calendar/Room/IManager.php b/lib/public/Calendar/Room/IManager.php
index eadb9c1669526..aaea1cb8ef689 100644
--- a/lib/public/Calendar/Room/IManager.php
+++ b/lib/public/Calendar/Room/IManager.php
@@ -13,49 +13,6 @@
  * @since 14.0.0
  */
 interface IManager {
-	/**
-	 * Registers a room backend
-	 *
-	 * @param string $backendClass
-	 * @return void
-	 * @since 14.0.0
-	 * @deprecated 24.0.0 use \OC\AppFramework\Bootstrap\::registerCalendarRoomBackend
-	 */
-	public function registerBackend(string $backendClass);
-
-	/**
-	 * Unregisters a room backend
-	 *
-	 * @param string $backendClass
-	 * @return void
-	 * @since 14.0.0
-	 * @deprecated 24.0.0
-	 */
-	public function unregisterBackend(string $backendClass);
-
-	/**
-	 * @return IBackend[]
-	 * @since 14.0.0
-	 * @deprecated 24.0.0
-	 */
-	public function getBackends():array;
-
-	/**
-	 * @param string $backendId
-	 * @return IBackend|null
-	 * @since 14.0.0
-	 * @deprecated 24.0.0
-	 */
-	public function getBackend($backendId);
-
-	/**
-	 * removes all registered backend instances
-	 * @return void
-	 * @since 14.0.0
-	 * @deprecated 24.0.0
-	 */
-	public function clear();
-
 	/**
 	 * Update all rooms from all backends right now.
 	 *
diff --git a/tests/lib/Calendar/Resource/ManagerTest.php b/tests/lib/Calendar/Resource/ManagerTest.php
index 69964d14aec47..c274e4c2b6f48 100644
--- a/tests/lib/Calendar/Resource/ManagerTest.php
+++ b/tests/lib/Calendar/Resource/ManagerTest.php
@@ -40,30 +40,6 @@ protected function setUp(): void {
 		);
 	}
 
-	public function testRegisterUnregisterBackend(): void {
-		$backend1 = $this->createMock(IBackend::class);
-		$backend1->method('getBackendIdentifier')->willReturn('backend_1');
-		$backend2 = $this->createMock(IBackend::class);
-		$backend2->method('getBackendIdentifier')->willReturn('backend_2');
-		$this->server->expects(self::exactly(2))
-			->method('get')
-			->willReturnMap([
-				['calendar_resource_backend1', $backend1,],
-				['calendar_resource_backend2', $backend2,],
-			]);
-
-		$this->manager->registerBackend('calendar_resource_backend1');
-		$this->manager->registerBackend('calendar_resource_backend2');
-
-		self::assertEquals([
-			$backend1, $backend2
-		], $this->manager->getBackends());
-		$this->manager->unregisterBackend('calendar_resource_backend1');
-		self::assertEquals([
-			$backend2
-		], $this->manager->getBackends());
-	}
-
 	public function testGetBackendFromBootstrapRegistration(): void {
 		$backendClass = '\\OCA\\CalendarResourceFoo\\Backend';
 		$backend = $this->createMock(IBackend::class);
@@ -85,49 +61,6 @@ public function testGetBackendFromBootstrapRegistration(): void {
 		self::assertEquals($backend, $this->manager->getBackend('from_bootstrap'));
 	}
 
-	public function testGetBackend(): void {
-		$backend1 = $this->createMock(IBackend::class);
-		$backend1->method('getBackendIdentifier')->willReturn('backend_1');
-		$backend2 = $this->createMock(IBackend::class);
-		$backend2->method('getBackendIdentifier')->willReturn('backend_2');
-		$this->server->expects(self::exactly(2))
-			->method('get')
-			->willReturnMap([
-				['calendar_resource_backend1', $backend1,],
-				['calendar_resource_backend2', $backend2,],
-			]);
-
-		$this->manager->registerBackend('calendar_resource_backend1');
-		$this->manager->registerBackend('calendar_resource_backend2');
-
-		self::assertEquals($backend1, $this->manager->getBackend('backend_1'));
-		self::assertEquals($backend2, $this->manager->getBackend('backend_2'));
-	}
-
-	public function testClear(): void {
-		$backend1 = $this->createMock(IBackend::class);
-		$backend1->method('getBackendIdentifier')->willReturn('backend_1');
-		$backend2 = $this->createMock(IBackend::class);
-		$backend2->method('getBackendIdentifier')->willReturn('backend_2');
-		$this->server->expects(self::exactly(2))
-			->method('get')
-			->willReturnMap([
-				['calendar_resource_backend1', $backend1,],
-				['calendar_resource_backend2', $backend2,],
-			]);
-
-		$this->manager->registerBackend('calendar_resource_backend1');
-		$this->manager->registerBackend('calendar_resource_backend2');
-
-		self::assertEquals([
-			$backend1, $backend2
-		], $this->manager->getBackends());
-
-		$this->manager->clear();
-
-		self::assertEquals([], $this->manager->getBackends());
-	}
-
 	public function testUpdate(): void {
 		$this->resourcesRoomsUpdater->expects(self::once())
 			->method('updateResources');
diff --git a/tests/lib/Calendar/ResourcesRoomsUpdaterTest.php b/tests/lib/Calendar/ResourcesRoomsUpdaterTest.php
index e74ba90c96532..323382b4b65c5 100644
--- a/tests/lib/Calendar/ResourcesRoomsUpdaterTest.php
+++ b/tests/lib/Calendar/ResourcesRoomsUpdaterTest.php
@@ -9,7 +9,9 @@
 
 namespace Test\Calendar;
 
+use OC\Calendar\Resource;
 use OC\Calendar\ResourcesRoomsUpdater;
+use OC\Calendar\Room;
 use OCA\DAV\CalDAV\CalDavBackend;
 use OCP\Calendar\BackendTemporarilyUnavailableException;
 use OCP\Calendar\IMetadataProvider;
@@ -26,32 +28,24 @@ interface tmpI extends IResource, IMetadataProvider {
 
 class ResourcesRoomsUpdaterTest extends TestCase {
 	private ResourcesRoomsUpdater $updater;
-
-	/** @var IResourceManager|MockObject */
-	private $resourceManager;
-
-	/** @var IRoomManager|MockObject */
-	private $roomManager;
-
-	/** @var ContainerInterface|MockObject */
-	private $container;
-
-	/** @var CalDavBackend|MockObject */
-	private $calDavBackend;
+	private Resource\Manager&MockObject $resourceManager;
+	private Room\Manager&MockObject $roomManager;
+	private ContainerInterface&MockObject $container;
+	private CalDavBackend&MockObject $calDavBackend;
 
 	#[\Override]
 	protected function setUp(): void {
 		parent::setUp();
 
-		$this->resourceManager = $this->createMock(IResourceManager::class);
-		$this->roomManager = $this->createMock(IRoomManager::class);
+		$this->resourceManager = $this->createMock(Resource\Manager::class);
+		$this->roomManager = $this->createMock(Room\Manager::class);
 		$this->container = $this->createMock(ContainerInterface::class);
 		$this->calDavBackend = $this->createMock(CalDavBackend::class);
 
 		$this->container->method('get')
 			->willReturnMap([
-				[IResourceManager::class, $this->resourceManager],
-				[IRoomManager::class, $this->roomManager],
+				[Resource\Manager::class, $this->resourceManager],
+				[Room\Manager::class, $this->roomManager],
 			]);
 
 		$this->updater = new ResourcesRoomsUpdater(
diff --git a/tests/lib/Calendar/Room/ManagerTest.php b/tests/lib/Calendar/Room/ManagerTest.php
index a678c58d0e7c9..4937dd2cef0b4 100644
--- a/tests/lib/Calendar/Room/ManagerTest.php
+++ b/tests/lib/Calendar/Room/ManagerTest.php
@@ -20,17 +20,10 @@
 use Test\TestCase;
 
 class ManagerTest extends TestCase {
-	/** @var Coordinator|MockObject */
-	private $coordinator;
-
-	/** @var ContainerInterface|MockObject */
-	private $server;
-
-	/** @var ResourcesRoomsUpdater|MockObject */
-	private $resourcesRoomsUpdater;
-
-	/** @var Manager */
-	private $manager;
+	private Coordinator&MockObject $coordinator;
+	private ContainerInterface&MockObject $server;
+	private ResourcesRoomsUpdater&MockObject $resourcesRoomsUpdater;
+	private Manager $manager;
 
 	#[\Override]
 	protected function setUp(): void {
@@ -47,32 +40,6 @@ protected function setUp(): void {
 		);
 	}
 
-	public function testRegisterUnregisterBackend(): void {
-		$backend1 = $this->createMock(IBackend::class);
-		$backend1->method('getBackendIdentifier')->willReturn('backend_1');
-		$backend2 = $this->createMock(IBackend::class);
-		$backend2->method('getBackendIdentifier')->willReturn('backend_2');
-		$this->server->expects(self::exactly(2))
-			->method('get')
-			->willReturnMap([
-				['calendar_room_backend1', $backend1,],
-				['calendar_room_backend2', $backend2,],
-			]);
-
-		$this->manager->registerBackend('calendar_room_backend1');
-		$this->manager->registerBackend('calendar_room_backend2');
-
-		self::assertEquals([
-			$backend1, $backend2
-		], $this->manager->getBackends());
-
-		$this->manager->unregisterBackend('calendar_room_backend1');
-
-		self::assertEquals([
-			$backend2
-		], $this->manager->getBackends());
-	}
-
 	public function testGetBackendFromBootstrapRegistration(): void {
 		$backendClass = '\\OCA\\CalendarRoomFoo\\Backend';
 		$backend = $this->createMock(IBackend::class);
@@ -94,49 +61,6 @@ public function testGetBackendFromBootstrapRegistration(): void {
 		self::assertEquals($backend, $this->manager->getBackend('from_bootstrap'));
 	}
 
-	public function testGetBackend(): void {
-		$backend1 = $this->createMock(IBackend::class);
-		$backend1->method('getBackendIdentifier')->willReturn('backend_1');
-		$backend2 = $this->createMock(IBackend::class);
-		$backend2->method('getBackendIdentifier')->willReturn('backend_2');
-		$this->server->expects(self::exactly(2))
-			->method('get')
-			->willReturnMap([
-				['calendar_room_backend1', $backend1,],
-				['calendar_room_backend2', $backend2,],
-			]);
-
-		$this->manager->registerBackend('calendar_room_backend1');
-		$this->manager->registerBackend('calendar_room_backend2');
-
-		self::assertEquals($backend1, $this->manager->getBackend('backend_1'));
-		self::assertEquals($backend2, $this->manager->getBackend('backend_2'));
-	}
-
-	public function testClear(): void {
-		$backend1 = $this->createMock(IBackend::class);
-		$backend1->method('getBackendIdentifier')->willReturn('backend_1');
-		$backend2 = $this->createMock(IBackend::class);
-		$backend2->method('getBackendIdentifier')->willReturn('backend_2');
-		$this->server->expects(self::exactly(2))
-			->method('get')
-			->willReturnMap([
-				['calendar_room_backend1', $backend1,],
-				['calendar_room_backend2', $backend2,],
-			]);
-
-		$this->manager->registerBackend('calendar_room_backend1');
-		$this->manager->registerBackend('calendar_room_backend2');
-
-		self::assertEquals([
-			$backend1, $backend2
-		], $this->manager->getBackends());
-
-		$this->manager->clear();
-
-		self::assertEquals([], $this->manager->getBackends());
-	}
-
 	public function testUpdate(): void {
 		$this->resourcesRoomsUpdater->expects(self::once())
 			->method('updateRooms');