fix: warnings

src/Register.php

@@ -67,7 +67,7 @@ public static function notificationIfNewer(Core\Notification $notification)
 			if (! $exNotification instanceof Core\Notification) {
 				// Something went wrong, just insert the notification.
 				Store\Notification::insert($notification->getHash(), $notification);
-				return;
+				return $notification;
 			}
 
 			// Existing Notification is newer or the same, do nothing.