Merge branch '5.1' into 5.2

* 5.1:
  Update introduction.rst
  Add warning about removed services

Author: javiereguiluz

create_framework/introduction.rst

@@ -62,7 +62,7 @@ Before You Start
 
 Reading about how to create a framework is not enough. You will have to follow
 along and actually type all the examples included in this tutorial. For that,
-you need a recent version of PHP (5.5.9 or later is good enough), a web server
+you need a recent version of PHP (7.4 or later is good enough), a web server
 (like Apache, nginx or PHP's built-in web server), a good knowledge of PHP and
 an understanding of Object Oriented programming.
 

testing.rst

@@ -580,6 +580,13 @@ container is a service that can be get via the normal container::
         // ...
     }
 
+.. caution::
+
+    The special container ``test.service_container`` doesn't give access to the
+    private services that have been removed (those who are not used by any
+    other services). The solution is to declare those private services as public
+    in the ``config/services_test.yaml`` file.
+
 .. tip::
 
     If the information you need to check is available from the profiler, use