diff --git a/apps/files_sharing/lib/Activity/Providers/Base.php b/apps/files_sharing/lib/Activity/Providers/Base.php
index 13bf3fea0e764..9df990258c820 100644
--- a/apps/files_sharing/lib/Activity/Providers/Base.php
+++ b/apps/files_sharing/lib/Activity/Providers/Base.php
@@ -122,9 +122,8 @@ protected function getFile($parameter, ?IEvent $event = null) {
 			$path = reset($parameter);
 			$id = (string)key($parameter);
 		} elseif ($event !== null) {
-			// Legacy from before ownCloud 8.2
 			$path = $parameter;
-			$id = $event->getObjectId();
+			$id = (string)$event->getObjectId();
 		} else {
 			throw new \InvalidArgumentException('Could not generate file parameter');
 		}