Fix #4874
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index b7be086..4c6143c 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -15,6 +15,11 @@
- Allowed PHP 4-style constructors (``Mathching_name::Matching_name()`` methods) to be used as routes, if there's a ``__construct()`` to override them.
+Bug fixes for 3.1.2
+-------------------
+
+- Fixed a regression (#4874) - :doc:`Session Library <libraries/sessions>` didn't take into account `session.hash_bits_per_character` when validating session IDs.
+
Version 3.1.1
=============