diff --git a/lib/Transport/Transport.php b/lib/Transport/Transport.php
index 620951d..4c2aa49 100644
--- a/lib/Transport/Transport.php
+++ b/lib/Transport/Transport.php
@@ -38,4 +38,6 @@ abstract class Transport {
 	}
 
 	abstract public function registerSubscription($options);
+
+	abstract public function notify(string $userId, string $collectionName, $data);
 }
\ No newline at end of file