[#7891] remove not needed sentence

Author: xabbuh

reference/configuration/framework.rst

@@ -134,8 +134,6 @@ recommended length is around 32 characters.
 In practice, Symfony uses this value for encrypting the cookies used
 in the :doc:`remember me functionality </security/remember_me>` and for
 creating signed URIs when using :ref:`ESI (Edge Side Includes) <edge-side-includes>`.
-Up to version 2.4, Symfony used this value for generating the
-:doc:`CSRF tokens </form/csrf_protection>`.
 
 This option becomes the service container parameter named ``kernel.secret``,
 which you can use whenever the application needs an immutable random string