diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index 69e6572..70c57d8 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -5,14 +5,18 @@
 
 namespace OCA\DavPush\AppInfo;
 
+use OCA\DavPush\Listener\SabrePluginAddListener;
+use OCA\DavPush\Listener\CalendarListener;
+
 use OCP\AppFramework\App;
 use OCP\AppFramework\Bootstrap\IBootstrap;
 use OCP\AppFramework\Bootstrap\IRegistrationContext;
 use OCP\AppFramework\Bootstrap\IBootContext;
 
 use OCA\DAV\Events\SabrePluginAddEvent;
-
-use OCA\DavPush\Listener\SabrePluginAddListener;
+use OCA\DAV\Events\CalendarObjectCreatedEvent;
+use OCA\DAV\Events\CalendarObjectDeletedEvent;
+use OCA\DAV\Events\CalendarObjectUpdatedEvent;
 
 class Application extends App implements IBootstrap {
 	public const APP_ID = 'dav_push';
@@ -23,6 +27,9 @@ class Application extends App implements IBootstrap {
 
 	public function register(IRegistrationContext $context): void {
 		$context->registerEventListener(SabrePluginAddEvent::class, SabrePluginAddListener::class);
+		$context->registerEventListener(CalendarObjectCreatedEvent::class, CalendarListener::class);
+        $context->registerEventListener(CalendarObjectDeletedEvent::class, CalendarListener::class);
+        $context->registerEventListener(CalendarObjectUpdatedEvent::class, CalendarListener::class);
 	}
 
 	public function boot(IBootContext $context): void {
diff --git a/lib/Db/SubscriptionMapper.php b/lib/Db/SubscriptionMapper.php
index 00e10dd..9cddbdc 100644
--- a/lib/Db/SubscriptionMapper.php
+++ b/lib/Db/SubscriptionMapper.php
@@ -32,4 +32,21 @@ class SubscriptionMapper extends QBMapper {
 		
 		return $this->findEntity($qb);
 	}
+
+	/**
+	 * @param string $userId
+	 * @param string $collectionName
+	 * @return Subscription[]
+	 */
+	public function findAll(string $userId, string $collectionName): array {
+		/* @var $qb IQueryBuilder */
+		$qb = $this->db->getQueryBuilder();
+
+		$qb->select('*')
+			->from(self::TABLENAME)
+			->where($qb->expr()->eq('user_id', $qb->createNamedParameter($userId)))
+			->andWhere($qb->expr()->eq('collection_name', $qb->createNamedParameter($collectionName)));
+		
+		return $this->findEntities($qb);
+	}
 }
\ No newline at end of file
diff --git a/lib/Listener/CalendarListener.php b/lib/Listener/CalendarListener.php
new file mode 100644
index 0000000..ed36026
--- /dev/null
+++ b/lib/Listener/CalendarListener.php
@@ -0,0 +1,71 @@
+<?php
+
+/**
+ * @copyright bitfire web engineering GmbH <info@bitfire.at>
+ *
+ * @author bitfire web engineering GmbH <info@bitfire.at>
+ * @author Jonathan Treffler <mail@jonathan-treffler.de>
+ *
+ * @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\DavPush\Listener;
+
+use OCP\IConfig;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+
+use OCA\DAV\Events\CalendarObjectCreatedEvent;
+use OCA\DAV\Events\CalendarObjectDeletedEvent;
+use OCA\DAV\Events\CalendarObjectUpdatedEvent;
+use OCA\DAV\Events\CardCreatedEvent;
+use OCA\DAV\Events\CardDeletedEvent;
+use OCA\DAV\Events\CardUpdatedEvent;
+
+use Psr\Log\LoggerInterface;
+
+use OCA\DavPush\Db\SubscriptionMapper;
+use OCA\DavPush\Transport\TransportManager;
+
+class CalendarListener implements IEventListener {
+
+    public function __construct(
+		private LoggerInterface $logger,
+		private SubscriptionMapper $subscriptionMapper,
+		private TransportManager $transportManager,
+		private $userId,
+	) {}
+
+    public function handle(Event $event): void {
+        if (!($event instanceOf CalendarObjectCreatedEvent) && !($event instanceOf CalendarObjectDeletedEvent) &&
+            !($event instanceOf CalendarObjectUpdatedEvent)) {
+            return;
+        }
+
+		$collectionName = $event->getCalendarData()['uri'];
+		$subscriptions = $this->subscriptionMapper->findAll($this->userId, $collectionName);
+
+		foreach($subscriptions as $subscription) {
+			$transport = $this->transportManager->getTransport($subscription->getTransport());
+			try {
+				$transport->notify($this->userId, $collectionName, json_decode($subscription->getData(), True));
+			} catch (Error $e) {
+				$this->logger->error("transport " .  $subscription->getTransport() . " failed to deliver notification to subscription " . $subscription->getId());
+			}
+		}
+    }
+}