diff --git a/CHANGELOG.md b/CHANGELOG.md
index 20fddaabd..261edb250 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -28,6 +28,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 
 - Update npm dependencies [#1123](https://github.com/nextcloud/integration_openproject/pull/1123)
+- Make OAuth2 Client class usage compatible with older Nextcloud versions [#1148](https://github.com/nextcloud/integration_openproject/pull/1148)
 
 ### Removed
 
diff --git a/lib/Controller/ConfigController.php b/lib/Controller/ConfigController.php
index 92ede69ee..4613bea6b 100755
--- a/lib/Controller/ConfigController.php
+++ b/lib/Controller/ConfigController.php
@@ -12,8 +12,8 @@
 use GuzzleHttp\Exception\GuzzleException;
 use InvalidArgumentException;
 use OC\User\NoUserException;
-use OCA\OAuth2\Controller\SettingsController;
 use OCA\OAuth2\Exceptions\ClientNotFoundException;
+use OCA\OAuth2\Service\ClientService;
 use OCA\OpenProject\AppInfo\Application;
 use OCA\OpenProject\Exception\OpenprojectErrorException;
 use OCA\OpenProject\Exception\OpenprojectGroupfolderSetupConflictException;
@@ -71,11 +71,6 @@ class ConfigController extends Controller {
 	 */
 	private $oauthService;
 
-	/**
-	 * @var SettingsController
-	 */
-	private $oauthSettingsController;
-
 	private SettingsService $settingsService;
 
 	public function __construct(
@@ -88,7 +83,7 @@ public function __construct(
 		OpenProjectAPIService $openprojectAPIService,
 		LoggerInterface $logger,
 		OauthService $oauthService,
-		SettingsController $oauthSettingsController,
+		private readonly ClientService $clientService,
 		SettingsService $settingsService,
 		?string $userId
 	) {
@@ -101,7 +96,6 @@ public function __construct(
 		$this->logger = $logger;
 		$this->userId = $userId;
 		$this->oauthService = $oauthService;
-		$this->oauthSettingsController = $oauthSettingsController;
 		$this->settingsService = $settingsService;
 	}
 
@@ -583,7 +577,7 @@ private function deleteOauthClient(): void {
 		if ($oauthClientInternalId !== '') {
 			$id = (int) $oauthClientInternalId;
 			try {
-				$this->oauthSettingsController->deleteClient($id);
+				$this->clientService->deleteClient($id);
 			} catch (ClientNotFoundException $e) {
 			}
 			$this->config->deleteAppValue(Application::APP_ID, 'nc_oauth_client_id');
diff --git a/lib/Service/OauthService.php b/lib/Service/OauthService.php
index bd4c5b520..973257a83 100644
--- a/lib/Service/OauthService.php
+++ b/lib/Service/OauthService.php
@@ -49,20 +49,24 @@ public function __construct(ClientMapper $clientMapper,
 	 */
 	public function createNcOauthClient(string $name, string $redirectUri): array {
 		$clientId = $this->secureRandom->generate(64, self::validChars);
+		$clientSecret = $this->secureRandom->generate(64, self::validChars);
+		$hashedClientSecret = bin2hex($this->crypto->calculateHMAC($clientSecret));
+		$redirectUri = sprintf($redirectUri, $clientId);
+
 		$client = new Client();
-		$client->setName($name);
-		$client->setRedirectUri(sprintf($redirectUri, $clientId));
-		$secret = $this->secureRandom->generate(64, self::validChars);
-		$client->setSecret(bin2hex($this->crypto->calculateHMAC($secret)));
-		$client->setClientIdentifier($clientId);
+		$this->setClientProperty($client, 'name', $name);
+		$this->setClientProperty($client, 'redirectUri', $redirectUri);
+		$this->setClientProperty($client, 'clientIdentifier', $clientId);
+		$this->setClientProperty($client, 'secret', $hashedClientSecret);
+
 		$client = $this->clientMapper->insert($client);
 
 		return [
-			'id' => $client->getId(),
-			'nextcloud_oauth_client_name' => $client->getName(),
-			'openproject_redirect_uri' => $client->getRedirectUri(),
-			'nextcloud_client_id' => $client->getClientIdentifier(),
-			'nextcloud_client_secret' => $secret,
+			'id' => $this->getClientProperty($client, 'id'),
+			'nextcloud_oauth_client_name' => $this->getClientProperty($client, 'name'),
+			'openproject_redirect_uri' => $this->getClientProperty($client, 'redirectUri'),
+			'nextcloud_client_id' => $this->getClientProperty($client, 'clientIdentifier'),
+			'nextcloud_client_secret' => $clientSecret,
 		];
 	}
 
@@ -74,10 +78,10 @@ public function getClientInfo(int $id): ?array {
 		try {
 			$client = $this->clientMapper->getByUid($id);
 			return [
-				'id' => $client->getId(),
-				'nextcloud_oauth_client_name' => $client->getName(),
-				'openproject_redirect_uri' => $client->getRedirectUri(),
-				'nextcloud_client_id' => $client->getClientIdentifier()
+				'id' => $this->getClientProperty($client, 'id'),
+				'nextcloud_oauth_client_name' => $this->getClientProperty($client, 'name'),
+				'openproject_redirect_uri' => $this->getClientProperty($client, 'redirectUri'),
+				'nextcloud_client_id' => $this->getClientProperty($client, 'clientIdentifier')
 			];
 		} catch (ClientNotFoundException $e) {
 			return null;
@@ -92,13 +96,53 @@ public function getClientInfo(int $id): ?array {
 	public function setClientRedirectUri(int $id, string $opUrl): bool {
 		try {
 			$client = $this->clientMapper->getByUid($id);
-			$clientId = $client->getClientIdentifier();
+			$clientId = $this->getClientProperty($client, 'clientIdentifier');
+
 			$redirectUri = rtrim($opUrl, '/') .'/oauth_clients/'.$clientId.'/callback';
-			$client->setRedirectUri($redirectUri);
+			$client = $this->setClientProperty($client, 'redirectUri', $redirectUri);
+
 			$this->clientMapper->update($client);
 			return true;
 		} catch (ClientNotFoundException $e) {
 			return false;
 		}
 	}
+
+	/**
+	 * @param Client $client
+	 * @param string $property
+	 * @param string|int $value
+	 *
+	 * @return Client
+	 */
+	public function setClientProperty(Client $client, string $property, string|int $value): Client {
+		$fn = 'set' . ucfirst($property);
+		// In NC35, OAuth2 Client class changed to attribute-based entity.
+		// NOTE: we can remove setClientProperty and getClientProperty methods
+		// once we drop support for NC34 and below.
+		if (\method_exists(Client::class, 'addType')) {
+			$client->$fn($value);
+		} else {
+			$client->{$property} = $value;
+		}
+
+		return $client;
+	}
+
+	/**
+	 * @param Client $client
+	 * @param string $property
+	 *
+	 * @return string|int
+	 */
+	public function getClientProperty(Client $client, string $property): string|int {
+		$fn = 'get' . ucfirst($property);
+		// In NC35, OAuth2 Client class changed to attribute-based entity.
+		// NOTE: we can remove setClientProperty and getClientProperty methods
+		// once we drop support for NC34 and below.
+		if (\method_exists(Client::class, 'addType')) {
+			return $client->$fn();
+		}
+		return $client->{$property};
+	}
 }
diff --git a/tests/lib/Controller/ConfigControllerTest.php b/tests/lib/Controller/ConfigControllerTest.php
index 318204b38..dc0181db5 100644
--- a/tests/lib/Controller/ConfigControllerTest.php
+++ b/tests/lib/Controller/ConfigControllerTest.php
@@ -8,7 +8,11 @@
 namespace OCA\OpenProject\Controller;
 
 use GuzzleHttp\Exception\ConnectException;
-use OCA\OAuth2\Controller\SettingsController;
+use OC\Authentication\Token\IProvider;
+use OCA\OAuth2\Db\AccessTokenMapper;
+use OCA\OAuth2\Db\Client;
+use OCA\OAuth2\Db\ClientMapper;
+use OCA\OAuth2\Service\ClientService;
 use OCA\OpenProject\AppInfo\Application;
 use OCA\OpenProject\Exception\OpenprojectErrorException;
 use OCA\OpenProject\Service\OauthService;
@@ -25,6 +29,7 @@
 use OCP\IURLGenerator;
 use OCP\IUser;
 use OCP\IUserManager;
+use OCP\Security\ICrypto;
 use OCP\Security\ISecureRandom;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
@@ -126,6 +131,32 @@ public function getSettingsService(): SettingsService {
 		);
 	}
 
+	/**
+	 * @param ClientMapper|null $clientMapper
+	 * @param IUserManager|null $userManager
+	 * @param AccessTokenMapper|null $accessTokenMapper
+	 *
+	 * @return ClientService
+	 */
+	public function getClientService(
+		ClientMapper $clientMapper = null,
+		AccessTokenMapper $accessTokenMapper = null,
+	): ClientService {
+		if ($clientMapper === null) {
+			$clientMapper = $this->createMock(ClientMapper::class);
+			$clientMapper->method('getByUid')->willReturn(new Client());
+		}
+		return new ClientService(
+			$this->createMock(ISecureRandom::class),
+			$this->createMock(ICrypto::class),
+			$clientMapper,
+			$this->createMock(IUserManager::class),
+			$this->createMock(IProvider::class),
+			$this->createMock(LoggerInterface::class),
+			$accessTokenMapper ?? $this->createMock(AccessTokenMapper::class),
+		);
+	}
+
 	/**
 	 * Format has to be [<string> => <object|string>] with the first being the constructor parameter name and the second one the mock.
 	 * Example: ['config' => $createdMockObject]
@@ -144,7 +175,7 @@ private function getConfigControllerConstructArgs(array $constructParams = []):
 			'openprojectAPIService' => $this->createMock(OpenProjectAPIService::class),
 			'loggerInterface' => $this->createMock(LoggerInterface::class),
 			'oauthService' => $this->createMock(OauthService::class),
-			'settingsController' => $this->createMock(SettingsController::class),
+			'clientService' => $this->getClientService(),
 			'settingsService' => $this->getSettingsService(),
 			'userId' => 'testUser'
 		];
@@ -768,9 +799,7 @@ public function testSetAdminConfigClearUserDataChangeNCOauthClient(
 
 		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
 		$oauthServiceMock = $this->createMock(OauthService::class);
-		$oauthSettingsControllerMock = $this->getMockBuilder(SettingsController::class)
-			->disableOriginalConstructor()
-			->getMock();
+
 		$configMock
 			->method('getAppValue')
 			->willReturnMap([
@@ -788,23 +817,31 @@ public function testSetAdminConfigClearUserDataChangeNCOauthClient(
 				[$testUser, Application::APP_ID, 'token', '', 'testtoken'],
 			]);
 
+		$clientService = $this->getClientService();
 		if ($updateNCOAuthClient) {
 			if ($updateNCOAuthClient === 'change') {
 				$oauthServiceMock
 					->expects($this->once())
 					->method('setClientRedirectUri')
 					->with(123, $credsToUpdate['openproject_instance_url']);
-				$oauthSettingsControllerMock
-					->expects($this->never())
-					->method('deleteClient');
+
+				$clientMapperMock = $this->createMock(ClientMapper::class);
+				$clientMapperMock->expects($this->never())->method('getByUid');
+				$clientMapperMock->expects($this->never())->method('delete');
+				$accessTokenMapperMock = $this->createMock(AccessTokenMapper::class);
+				$accessTokenMapperMock->expects($this->never())->method('deleteByClientId');
+				$clientService = $this->getClientService($clientMapperMock, $accessTokenMapperMock);
 			} else { // delete the client
 				$oauthServiceMock
 					->expects($this->never())
 					->method('setClientRedirectUri');
-				$oauthSettingsControllerMock
-					->expects($this->once())
-					->method('deleteClient')
-					->with(123);
+
+				$clientMapperMock = $this->createMock(ClientMapper::class);
+				$clientMapperMock->expects($this->once())->method('getByUid')->willReturn(new Client());
+				$clientMapperMock->expects($this->once())->method('delete');
+				$accessTokenMapperMock = $this->createMock(AccessTokenMapper::class);
+				$accessTokenMapperMock->expects($this->once())->method('deleteByClientId');
+				$clientService = $this->getClientService($clientMapperMock, $accessTokenMapperMock);
 			}
 		} else {
 			$oauthServiceMock->expects($this->never())->method('setClientRedirectUri');
@@ -845,7 +882,7 @@ public function testSetAdminConfigClearUserDataChangeNCOauthClient(
 			'userManager' => $userManager,
 			'openprojectAPIService' => $apiService,
 			'oauthService' => $oauthServiceMock,
-			'settingsController' => $oauthSettingsControllerMock,
+			'clientService' => $clientService,
 			'userId' => 'test101'
 		]);
 		$configController = new ConfigController(...$constructArgs);
@@ -984,7 +1021,6 @@ public function testSetAdminConfigForOPOAuthTokenRevoke(array $oldConfig, array
 			->getMock();
 		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
 		$oauthServiceMock = $this->createMock(OauthService::class);
-		$oauthSettingsControllerMock = $this->createMock('OCA\OAuth2\Controller\SettingsController');
 
 		if ($mode === "reset") {
 			$this->expectMethodCalls($configMock, 'deleteAppValue', [
@@ -1060,7 +1096,6 @@ public function testSetAdminConfigForOPOAuthTokenRevoke(array $oldConfig, array
 			'userManager' => $userManager,
 			'openprojectAPIService' => $apiService,
 			'oauthService' => $oauthServiceMock,
-			'settingsController' => $oauthSettingsControllerMock,
 			'userId' => 'test101'
 		]);
 		$configController = new ConfigController(...$constructArgs);
@@ -1118,7 +1153,6 @@ public function testOPOAuthTokenRevokeErrors($errorCode, $exception, $errMessage
 			->getMock();
 		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
 		$oauthServiceMock = $this->createMock(OauthService::class);
-		$oauthSettingsControllerMock = $this->createMock('OCA\OAuth2\Controller\SettingsController');
 		$loggerInterfaceMock = $this->createMock(LoggerInterface::class);
 
 		$this->expectMethodCalls($configMock, 'getAppValue', [
@@ -1196,7 +1230,6 @@ public function testOPOAuthTokenRevokeErrors($errorCode, $exception, $errMessage
 			'openprojectAPIService' => $apiService,
 			'loggerInterface' => $loggerInterfaceMock,
 			'oauthService' => $oauthServiceMock,
-			'settingsController' => $oauthSettingsControllerMock,
 			'userId' => 'admin'
 		]);
 		$configController = new ConfigController(...$constructArgs);
@@ -1228,7 +1261,6 @@ public function testOPOAuthTokenRevokeDoesNotOccurIfNoOPOAuthClientHasChanged()
 			->getMock();
 		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
 		$oauthServiceMock = $this->createMock(OauthService::class);
-		$oauthSettingsControllerMock = $this->createMock('OCA\OAuth2\Controller\SettingsController');
 		$loggerInterfaceMock = $this->createMock(LoggerInterface::class);
 
 		$configMock
@@ -1256,7 +1288,6 @@ public function testOPOAuthTokenRevokeDoesNotOccurIfNoOPOAuthClientHasChanged()
 			'openprojectAPIService' => $apiService,
 			'loggerInterface' => $loggerInterfaceMock,
 			'oauthService' => $oauthServiceMock,
-			'settingsController' => $oauthSettingsControllerMock,
 			'userId' => 'admin'
 		]);
 		$configController = new ConfigController(...$constructArgs);
@@ -1476,9 +1507,6 @@ public function testSetAdminConfigOIDCAuthSetting(
 		$userManager = $this->checkForUsersCountBeforeTest();
 		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
 		$oauthServiceMock = $this->createMock(OauthService::class);
-		$oauthSettingsControllerMock = $this->getMockBuilder(SettingsController::class)
-			->disableOriginalConstructor()
-			->getMock();
 		$configMock
 			->method('getAppValue')
 			->willReturnMap([
@@ -1504,7 +1532,6 @@ public function testSetAdminConfigOIDCAuthSetting(
 			'userManager' => $userManager,
 			'openprojectAPIService' => $apiService,
 			'oauthService' => $oauthServiceMock,
-			'settingsController' => $oauthSettingsControllerMock,
 			'userId' => 'test101'
 		]);
 		$configController = new ConfigController(...$constructArgs);
@@ -1563,9 +1590,6 @@ public function testSetAdminConfigForOAuth2AlreadyConfigured(
 
 		$configMock = $this->createMock(IConfig::class);
 		$oauthServiceMock = $this->createMock(OauthService::class);
-		$oauthSettingsControllerMock = $this->getMockBuilder(SettingsController::class)
-			->disableOriginalConstructor()
-			->getMock();
 		$this->expectMethodCalls($configMock, 'getAppValue', [
 			[['integration_openproject', 'openproject_instance_url', ''], $oldCreds['openproject_instance_url']],
 			[['integration_openproject', 'authorization_method', ''], $oldCreds['authorization_method']],
@@ -1578,14 +1602,7 @@ public function testSetAdminConfigForOAuth2AlreadyConfigured(
 			[['integration_openproject', 'openproject_client_secret', ''], $credsToUpdate['openproject_client_secret']],
 			[['integration_openproject', 'openproject_instance_url', ''], $credsToUpdate['openproject_instance_url']],
 		]);
-		$oauthSettingsControllerMock
-			->expects($this->once())
-			->method('deleteClient')
-			->with(123);
-		$oauthSettingsControllerMock
-			->expects($this->once())
-			->method('deleteClient')
-			->with(123);
+
 		$configMock
 			->expects($this->exactly(12))
 			->method('deleteUserValue')
@@ -1604,6 +1621,13 @@ public function testSetAdminConfigForOAuth2AlreadyConfigured(
 				[$this->user1->getUID(), 'integration_openproject', 'token_expires_at', null],
 			]);
 
+		$clientMapperMock = $this->createMock(ClientMapper::class);
+		$clientMapperMock->expects($this->once())->method('getByUid')->willReturn(new Client());
+		$clientMapperMock->expects($this->once())->method('delete');
+		$accessTokenMapperMock = $this->createMock(AccessTokenMapper::class);
+		$accessTokenMapperMock->expects($this->once())->method('deleteByClientId');
+		$clientService = $this->getClientService($clientMapperMock, $accessTokenMapperMock);
+
 		$apiService = $this->getMockBuilder(OpenProjectAPIService::class)
 			->disableOriginalConstructor()
 			->getMock();
@@ -1613,7 +1637,7 @@ public function testSetAdminConfigForOAuth2AlreadyConfigured(
 			'userManager' => $userManager,
 			'openprojectAPIService' => $apiService,
 			'oauthService' => $oauthServiceMock,
-			'settingsController' => $oauthSettingsControllerMock,
+			'clientService' => $clientService,
 			'userId' => 'test101'
 		]);
 		$configController = new ConfigController(...$constructArgs);
@@ -1674,9 +1698,6 @@ public function testSetAdminConfigForOIDCAlreadyConfigured(
 		$this->user1 = $userManager->createUser($testUser, $testUser);
 		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
 		$oauthServiceMock = $this->createMock(OauthService::class);
-		$oauthSettingsControllerMock = $this->getMockBuilder(SettingsController::class)
-			->disableOriginalConstructor()
-			->getMock();
 
 		$this->expectMethodCalls($configMock, 'getAppValue', [
 			[['integration_openproject', 'openproject_instance_url', ''], $oldConfig['openproject_instance_url']],
@@ -1714,7 +1735,6 @@ public function testSetAdminConfigForOIDCAlreadyConfigured(
 			'userManager' => $userManager,
 			'openprojectAPIService' => $apiService,
 			'oauthService' => $oauthServiceMock,
-			'settingsController' => $oauthSettingsControllerMock,
 			'userId' => $testUser,
 		]);
 
diff --git a/tests/lib/Service/OauthServiceTest.php b/tests/lib/Service/OauthServiceTest.php
index 78464da9f..a89b34448 100644
--- a/tests/lib/Service/OauthServiceTest.php
+++ b/tests/lib/Service/OauthServiceTest.php
@@ -42,17 +42,52 @@ protected function getOauthServiceMock(MockObject $clientMapperMock = null): Oau
 	/**
 	 * @return Client
 	 */
-	protected function getClient(int $clientId): Client {
+	protected function getClient(int $clientDbId): Client {
 		$client = new Client();
-		$client->setId($clientId);
-		$client->setName('Test Client');
-		$client->setRedirectUri('https://example.com/callback');
-		$client->setClientIdentifier('randomString');
-		$client->setSecret('randomString');
+		$name = 'Test Client';
+		$redirectUri = 'https://example.com/callback';
+		$clientId = 'randomString';
+		$clientSecret = 'randomString';
+
+		$this->setClientProperty($client, 'id', $clientDbId);
+		$this->setClientProperty($client, 'name', $name);
+		$this->setClientProperty($client, 'redirectUri', $redirectUri);
+		$this->setClientProperty($client, 'clientIdentifier', $clientId);
+		$this->setClientProperty($client, 'secret', $clientSecret);
+		return $client;
+	}
 
+	/**
+	 * @param Client $client
+	 * @param string $property
+	 * @param string|int $value
+	 *
+	 * @return Client
+	 */
+	protected function setClientProperty(Client $client, string $property, string|int $value): Client {
+		$fn = 'set' . ucfirst($property);
+		if (\method_exists(Client::class, 'addType')) {
+			$client->$fn($value);
+		} else {
+			$client->{$property} = $value;
+		}
 		return $client;
 	}
 
+	/**
+	 * @param Client $client
+	 * @param string $property
+	 *
+	 * @return string|int
+	 */
+	protected function getClientProperty(Client $client, string $property): string|int {
+		$fn = 'get' . ucfirst($property);
+		if (\method_exists(Client::class, 'addType')) {
+			return $client->$fn();
+		}
+		return $client->{$property};
+	}
+
 	/**
 	 * @return void
 	 */
@@ -61,23 +96,25 @@ public function testCreateNcOauthClient(): void {
 		$testClient = $this->getClient($clientId);
 		$expectedClient = [
 			'id' => $clientId,
-			'nextcloud_oauth_client_name' => $testClient->getName(),
-			'openproject_redirect_uri' => $testClient->getRedirectUri(),
-			'nextcloud_client_id' => $testClient->getClientIdentifier(),
-			'nextcloud_client_secret' => $testClient->getSecret(),
+			'nextcloud_oauth_client_name' => $this->getClientProperty($testClient, 'name'),
+			'openproject_redirect_uri' => $this->getClientProperty($testClient, 'redirectUri'),
+			'nextcloud_client_id' => $this->getClientProperty($testClient, 'clientIdentifier'),
+			'nextcloud_client_secret' => $this->getClientProperty($testClient, 'secret'),
 		];
 
 		$clientMapperMock = $this->createMock(ClientMapper::class);
 		$clientMapperMock->expects($this->once())->method('insert')
 			->with($this->isInstanceOf(Client::class))
 			->willReturnCallback(function ($client) use ($clientId) {
-				$client->setId($clientId);
-				return $client;
+				return $this->setClientProperty($client, 'id', $clientId);
 			});
 
 		$oauthService = $this->getOauthServiceMock($clientMapperMock);
 
-		$clientInfo = $oauthService->createNcOauthClient($testClient->getName(), $testClient->getRedirectUri());
+		$clientInfo = $oauthService->createNcOauthClient(
+			(string)$this->getClientProperty($testClient, 'name'),
+			(string)$this->getClientProperty($testClient, 'redirectUri')
+		);
 		$this->assertSame($expectedClient, $clientInfo);
 	}
 
@@ -89,9 +126,9 @@ public function testGetClientInfo(): void {
 		$client = $this->getClient($clientId);
 		$expectedClient = [
 			'id' => $clientId,
-			'nextcloud_oauth_client_name' => $client->getName(),
-			'openproject_redirect_uri' => $client->getRedirectUri(),
-			'nextcloud_client_id' => $client->getClientIdentifier(),
+			'nextcloud_oauth_client_name' => $this->getClientProperty($client, 'name'),
+			'openproject_redirect_uri' => $this->getClientProperty($client, 'redirectUri'),
+			'nextcloud_client_id' => $this->getClientProperty($client, 'clientIdentifier'),
 		];
 
 		$clientMapperMock = $this->createMock(ClientMapper::class);
@@ -138,7 +175,10 @@ public function testSetClientRedirectUri(): void {
 
 		$oauthService = $this->getOauthServiceMock($clientMapperMock);
 
-		$result = $oauthService->setClientRedirectUri($clientId, $client->getRedirectUri());
+		$result = $oauthService->setClientRedirectUri(
+			$clientId,
+			(string)$this->getClientProperty($client, 'redirectUri'),
+		);
 		$this->assertTrue($result);
 	}
 
@@ -157,7 +197,10 @@ public function testSetClientRedirectUriError(): void {
 
 		$oauthService = $this->getOauthServiceMock($clientMapperMock);
 
-		$result = $oauthService->setClientRedirectUri($clientId, $client->getRedirectUri());
+		$result = $oauthService->setClientRedirectUri(
+			$clientId,
+			(string)$this->getClientProperty($client, 'redirectUri'),
+		);
 		$this->assertFalse($result);
 	}
 }