[Security] Add deprecation notices about Guard authenticators

security.rst

@@ -462,6 +462,11 @@ you to control *every* part of the authentication process (see the next section)
 Guard Authenticators
 ~~~~~~~~~~~~~~~~~~~~
 
+.. deprecated:: 5.3
+
+    Guard authenticators are deprecated since Symfony 5.3 in favor of the
+    :doc:`new authenticator-based system </security/authenticator_manager>`.
+
 A Guard authenticator is a class that gives you *complete* control over your
 authentication process. There are many different ways to build an authenticator;
 here are a few common use-cases:

security/auth_providers.rst

@@ -1,9 +1,9 @@
 Built-in Authentication Providers
 =================================
 
-If you need to add authentication to your app, we recommend using
-:doc:`Guard authentication </security/guard_authentication>` because it gives you
-full control over the process.
+If you need to add authentication to your app, we recommend using the
+:doc:`new authenticator-based system </security/authenticator_manager>` because
+it gives you full control over the process.
 
 But, Symfony also offers a number of built-in authentication providers: systems
 that are easier to implement, but harder to customize. If your authentication

security/custom_authentication_provider.rst

@@ -7,10 +7,8 @@ How to Create a custom Authentication Provider
 .. caution::
 
     Creating a custom authentication system is hard, and almost definitely
-    **not** needed. Instead, see :doc:`/security/guard_authentication` for a
-    simple way to create an authentication system you will love. Do **not**
-    keep reading unless you want to learn the lowest level details of
-    authentication.
+    **not** needed. Instead, see the
+    :doc:`new authenticator-based system </security/authenticator_manager>`
 
 Symfony provides support for the most
 :doc:`common authentication mechanisms </security/auth_providers>`. However, your

security/guard_authentication.rst

@@ -4,6 +4,11 @@
 Custom Authentication System with Guard (API Token Example)
 ===========================================================
 
+.. deprecated:: 5.3
+
+    Guard authenticators are deprecated since Symfony 5.3 in favor of the
+    :doc:`new authenticator-based system </security/authenticator_manager>`.
+
 Guard authentication can be used to:
 
 * :doc:`Build a Login Form </security/form_login_setup>`
@@ -14,11 +19,6 @@ Guard authentication can be used to:
 and many more. In this example, we'll build an API token authentication
 system, so we can learn more about Guard in detail.
 
-.. tip::
-
-    A :doc:`new authenticator-based system </security/authenticator_manager>`
-    was introduced in Symfony 5.1, which will eventually replace Guards in Symfony 6.0.
-
 Step 1) Prepare your User Class
 -------------------------------
 

security/multiple_guard_authenticators.rst

@@ -1,6 +1,11 @@
 How to Use Multiple Guard Authenticators
 ========================================
 
+.. deprecated:: 5.3
+
+    Guard authenticators are deprecated since Symfony 5.3 in favor of the
+    :doc:`new authenticator-based system </security/authenticator_manager>`.
+
 The Guard authentication component allows you to use many different
 authenticators at a time.