diff --git a/Backend/AMQPBackend.php b/Backend/AMQPBackend.php
index <HASH>..<HASH> 100644
--- a/Backend/AMQPBackend.php
+++ b/Backend/AMQPBackend.php
@@ -37,6 +37,9 @@ class AMQPBackend implements BackendInterface
      */
     protected $queue;
 
+    /**
+     * @deprecated since version 2.4 and will be removed in 3.0.
+     */
     protected $connection;
 
     /**
connection in AMQPBackend is deprecated