Polish changes following PR #3573
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 5c5cd5e..bc3ea34 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -767,6 +767,7 @@
- Fixed a bug in :doc:`Zip Library <libraries/zip>` internal method ``_get_mod_time()`` where it was not parsing result returned by ``filemtime()``.
- Fixed a bug (#3161) - :doc:`Cache Library <libraries/caching>` methods `increment()`, `decrement()` didn't auto-create non-existent items when using redis and/or file storage.
- Fixed a bug (#3189) - :doc:`Parser Library <libraries/parser>` used double replacement on ``key->value`` pairs, exposing a potential template injection vulnerability.
+- Fixed a bug (#3573) - :doc:`Email Library <libraries/email>` violated `RFC5321 <https://tools.ietf.org/rfc/rfc5321.txt>`_ by sending 'localhost.localdomain' as a hostname.
Version 2.2.1
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