diff --git a/security/form_login_setup.rst b/security/form_login_setup.rst
index d8974204634..0cd11eee4a7 100644
--- a/security/form_login_setup.rst
+++ b/security/form_login_setup.rst
@@ -157,6 +157,10 @@ Great! Next, add the logic to ``loginAction()`` that displays the login form::
         ));
     }
 
+Please note that the controller autoresolve the AuthenticationUtils injection
+only if defined as a service. Since Symfony 3.3, this comportment is adopted 
+by default in the services.yml file.
+
 Don't let this controller confuse you. As you'll see in a moment, when the
 user submits the form, the security system automatically handles the form
 submission for you. If the user submits an invalid username or password,