diff --git a/src/MessageBird/Objects/Message.php b/src/MessageBird/Objects/Message.php
index 667f6246..6873bff7 100644
--- a/src/MessageBird/Objects/Message.php
+++ b/src/MessageBird/Objects/Message.php
@@ -5,6 +5,7 @@
 /**
  * Class Message
  *
+ * @property int $protocolId
  * @package MessageBird\Objects
  */
 class Message extends Base