diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 4ca8972dc1..074611533e 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -11,6 +11,7 @@ Changelog
  * Support the rel attribute on custom ModelAdmin buttons (Andy Chosak)
  * Server-side page slug generation now respects `WAGTAIL_ALLOW_UNICODE_SLUGS` (Arkadiusz Michał Ryś)
  * Wagtail admin no longer depends on SiteMiddleware, avoiding incompatibility with Django sites framework and redundant database queries (aritas1, timmysmalls, Matt Westcott)
+ * Tag field autocompletion now handles custom tag models (Matt Westcott)
  * Fix: Added ARIA alert role to live search forms in the admin (Casper Timmers)
  * Fix: Reorder login form elements to match expected tab order (Kjartan Sverrisson)
  * Fix: Re-add 'Close Explorer' button on mobile viewports (Sævar Öfjörð Magnússon)
diff --git a/docs/releases/2.9.rst b/docs/releases/2.9.rst
index 8992719275..95c609f78a 100644
--- a/docs/releases/2.9.rst
+++ b/docs/releases/2.9.rst
@@ -21,6 +21,7 @@ Other features
  * Support the rel attribute on custom ModelAdmin buttons (Andy Chosak)
  * Server-side page slug generation now respects ``WAGTAIL_ALLOW_UNICODE_SLUGS`` (Arkadiusz Michał Ryś)
  * Wagtail admin no longer depends on SiteMiddleware, avoiding incompatibility with Django sites framework and redundant database queries (aritas1, timmysmalls, Matt Westcott)
+ * Tag field autocompletion now handles custom tag models (Matt Westcott)
 
 
 Bug fixes