Removed the versionadded directives

Author: javiereguiluz

components/serializer.rst

@@ -719,10 +719,6 @@ There are several types of normalizers available:
     This normalizer converts :phpclass:`DateTimeZone` objects into strings that
     represent the name of the timezone according to the `list of PHP timezones`_.
 
-    .. versionadded:: 4.3
-
-        The ``DateTimeZoneNormalizer`` was introduced in Symfony 4.3.
-
 :class:`Symfony\\Component\\Serializer\\Normalizer\\DataUriNormalizer`
     This normalizer converts :phpclass:`SplFileInfo` objects into a data URI
     string (``data:...``) such that files can be embedded into serialized data.

serializer.rst

@@ -70,10 +70,6 @@ As well as the following normalizers:
 * :class:`Symfony\\Component\\Serializer\\Normalizer\\ArrayDenormalizer` to
   denormalize arrays of objects using a format like `MyObject[]` (note the `[]` suffix)
 
-.. versionadded:: 4.3
-
-    The ``DateTimeZoneNormalizer`` was introduced in Symfony 4.3.
-
 Custom normalizers and/or encoders can also be loaded by tagging them as
 :ref:`serializer.normalizer <reference-dic-tags-serializer-normalizer>` and
 :ref:`serializer.encoder <reference-dic-tags-serializer-encoder>`. It's also