Merge branch '4.4' into 5.0

* 4.4:
  Fixed minimum PHP version for v4.4

Author: javiereguiluz

contributing/code/pull_requests.rst

@@ -25,7 +25,7 @@ Before working on Symfony, setup a friendly environment with the following
 software:
 
 * Git;
-* PHP version 5.5.9 or above.
+* PHP version 7.1.3 or above.
 
 Configure Git
 ~~~~~~~~~~~~~