diff --git a/apps/files_external/lib/AppInfo/Application.php b/apps/files_external/lib/AppInfo/Application.php
index b1b7b3084f..162c0eb331 100644
--- a/apps/files_external/lib/AppInfo/Application.php
+++ b/apps/files_external/lib/AppInfo/Application.php
@@ -32,6 +32,8 @@ namespace OCA\Files_External\AppInfo;
 
 use OCA\Files_External\Config\ConfigAdapter;
 use OCA\Files_External\Config\UserPlaceholderHandler;
+use OCA\Files_External\Listener\GroupDeletedListener;
+use OCA\Files_External\Listener\UserDeletedListener;
 use OCA\Files_External\Service\DBConfigService;
 use OCA\Files_External\Lib\Auth\AmazonS3\AccessKey;
 use OCA\Files_External\Lib\Auth\Builtin;
@@ -68,8 +70,10 @@ use OCP\AppFramework\Bootstrap\IBootContext;
 use OCP\AppFramework\Bootstrap\IBootstrap;
 use OCP\AppFramework\Bootstrap\IRegistrationContext;
 use OCP\Files\Config\IMountProviderCollection;
+use OCP\Group\Events\GroupDeletedEvent;
 use OCP\IGroup;
 use OCP\IUser;
+use OCP\User\Events\UserDeletedEvent;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\EventDispatcher\GenericEvent;
 
@@ -104,7 +108,8 @@ class Application extends App implements IBackendProvider, IAuthMechanismProvide
 	}
 
 	public function register(IRegistrationContext $context): void {
-		// TODO: Implement register() method.
+		$context->registerEventListener(UserDeletedEvent::class, UserDeletedListener::class);
+		$context->registerEventListener(GroupDeletedEvent::class, GroupDeletedListener::class);
 	}
 
 	public function boot(IBootContext $context): void {
@@ -124,30 +129,6 @@ class Application extends App implements IBackendProvider, IAuthMechanismProvide
 		$context->injectFn([$this, 'registerListeners']);
 	}
 
-
-	public function registerListeners(EventDispatcherInterface $dispatcher) {
-		$dispatcher->addListener(
-			IUser::class . '::postDelete',
-			function (GenericEvent $event) {
-				/** @var IUser $user */
-				$user = $event->getSubject();
-				/** @var DBConfigService $config */
-				$config = $this->getContainer()->query(DBConfigService::class);
-				$config->modifyMountsOnUserDelete($user->getUID());
-			}
-		);
-		$dispatcher->addListener(
-			IGroup::class . '::postDelete',
-			function (GenericEvent $event) {
-				/** @var IGroup $group */
-				$group = $event->getSubject();
-				/** @var DBConfigService $config */
-				$config = $this->getContainer()->query(DBConfigService::class);
-				$config->modifyMountsOnGroupDelete($group->getGID());
-			}
-		);
-	}
-
 	/**
 	 * @{inheritdoc}
 	 */
diff --git a/apps/files_external/lib/Listener/GroupDeletedListener.php b/apps/files_external/lib/Listener/GroupDeletedListener.php
new file mode 100644
index 0000000000..d274f35d9c
--- /dev/null
+++ b/apps/files_external/lib/Listener/GroupDeletedListener.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Robin Appelman <robin@icewind.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Files_External\Listener;
+
+use OCA\Files_External\Service\DBConfigService;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use OCP\Group\Events\GroupDeletedEvent;
+
+class GroupDeletedListener implements IEventListener {
+	/** @var DBConfigService */
+	private $config;
+
+	public function __construct(DBConfigService $config) {
+		$this->config = $config;
+	}
+
+	public function handle(Event $event): void {
+		if (!$event instanceof GroupDeletedEvent) {
+			return;
+		}
+		$this->config->modifyMountsOnGroupDelete($event->getGroup()->getGID());
+	}
+}
diff --git a/apps/files_external/lib/Listener/UserDeletedListener.php b/apps/files_external/lib/Listener/UserDeletedListener.php
new file mode 100644
index 0000000000..1417119b31
--- /dev/null
+++ b/apps/files_external/lib/Listener/UserDeletedListener.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2021 Robin Appelman <robin@icewind.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Files_External\Listener;
+
+use OCA\Files_External\Service\DBConfigService;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use OCP\User\Events\UserDeletedEvent;
+
+class UserDeletedListener implements IEventListener {
+	/** @var DBConfigService */
+	private $config;
+
+	public function __construct(DBConfigService $config) {
+		$this->config = $config;
+	}
+
+	public function handle(Event $event): void {
+		if (!$event instanceof UserDeletedEvent) {
+			return;
+		}
+		$this->config->modifyMountsOnUserDelete($event->getUser()->getUID());
+	}
+}