diff --git a/lib/BackgroundJob.php b/lib/BackgroundJob.php
index f05a264..97ce9a1 100644
--- a/lib/BackgroundJob.php
+++ b/lib/BackgroundJob.php
@@ -95,7 +95,7 @@ protected function createPublicity($id, $authorId, $timeStamp) {
 		$notification = $this->notificationManager->createNotification();
 		$notification->setApp('announcementcenter')
 			->setDateTime($dateTime)
-			->setObject('announcement', $id)
+			->setObject('announcement', (string) $id)
 			->setSubject('announced', [$authorId])
 			->setLink($this->urlGenerator->linkToRoute('announcementcenter.page.index'));
 
diff --git a/lib/Controller/PageController.php b/lib/Controller/PageController.php
index 55e6584..5e735c3 100644
--- a/lib/Controller/PageController.php
+++ b/lib/Controller/PageController.php
@@ -153,7 +153,7 @@ public function delete($id) {
 
 		$notification = $this->notificationManager->createNotification();
 		$notification->setApp('announcementcenter')
-			->setObject('announcement', $id);
+			->setObject('announcement', (string) $id);
 		$this->notificationManager->markProcessed($notification);
 
 		return new Response();