diff --git a/messenger/custom-transport.rst b/messenger/custom-transport.rst
index 045f8ffa389..09b356407ac 100644
--- a/messenger/custom-transport.rst
+++ b/messenger/custom-transport.rst
@@ -17,7 +17,7 @@ DSN. You will need a transport factory::
 
     class YourTransportFactory implements TransportFactoryInterface
     {
-        public function createTransport(string $dsn, array $options): TransportInterface
+        public function createTransport(string $dsn, array $options, SerializerInterface $serializer): TransportInterface
         {
             return new YourTransport(/* ... */);
         }