Add a note block

Author: dunglas

components/serializer.rst

@@ -481,8 +481,11 @@ and :class:`Symfony\\Component\\Serializer\\Normalizer\\PropertyNormalizer`::
     $companyCopy = $serializer->deserialize($json, Company::class, 'json');
     // Same data as $company
 
-It is also possible to access to the current class name, format and context by implementing the
-:class:`Symfony\\Component\\Serializer\\NameConverter\\AdvancedNameConverterInterface` interface.
+.. note::
+
+    Since Symfony 4.2, it is also possible to access to the current class name, format and
+    context by implementing the :class:`Symfony\\Component\\Serializer\\NameConverter\\AdvancedNameConverterInterface`
+    interface.
 
 .. _using-camelized-method-names-for-underscored-attributes: