diff --git a/user_guide_src/source/changelogs/v4.5.8.rst b/user_guide_src/source/changelogs/v4.5.8.rst
index cad7fec30248..17f8dd0d2d7d 100644
--- a/user_guide_src/source/changelogs/v4.5.8.rst
+++ b/user_guide_src/source/changelogs/v4.5.8.rst
@@ -18,6 +18,17 @@ BREAKING
 Message Changes
 ***************
 
+************
+Enhancements
+************
+
+Negotiator
+==========
+
+- Added a feature flag ``Feature::$simpleNegotiateLocale`` fix simple locale comparison.
+  Previously, response with language headers ``Accept-language: en-US,en-GB;q=0.9`` returned the first allowed language ``en`` could instead of the exact language ``en-US`` or ``en-GB``.
+  Set the value to ``false`` to be able to get ``en-*``
+
 *******
 Changes
 *******
diff --git a/user_guide_src/source/installation/upgrade_458.rst b/user_guide_src/source/installation/upgrade_458.rst
index e8e8e681abe4..69a6fe92da9d 100644
--- a/user_guide_src/source/installation/upgrade_458.rst
+++ b/user_guide_src/source/installation/upgrade_458.rst
@@ -44,7 +44,10 @@ and it is recommended that you merge the updated versions with your application:
 Config
 ------
 
-- @TODO
+app/Config/Feature.php
+^^^^^^^^^^^^^^^^^^^^^^
+
+- ``Config\Feature::$simpleNegotiateLocale`` has been added.
 
 All Changes
 ===========
@@ -52,4 +55,4 @@ All Changes
 This is a list of all files in the **project space** that received changes;
 many will be simple comments or formatting that have no effect on the runtime:
 
-- @TODO
+- app/Config/Feature.php