[2.3] Add note about implemented version

aitboudad · aitboudad · commit 838bb8b917e3 · 2013-04-22T07:52:54.000Z
diff --git a/reference/constraints/Isbn.rst b/reference/constraints/Isbn.rst
@@ -1,6 +1,9 @@
 Isbn
 ====
 
+.. versionadded:: New in version 2.3:
+    The Isbn validation were added in Symfony 2.3.
+
 This constraint permits that a ISBN (International Standard Book Numbers)
 number is either a valid ISBN-10, a valid ISBN-13 code or both on a value.
 
