diff --git a/guides/source/5_0_release_notes.md b/guides/source/5_0_release_notes.md
index 28f653b634..5f14a5a3f9 100644
--- a/guides/source/5_0_release_notes.md
+++ b/guides/source/5_0_release_notes.md
@@ -227,6 +227,9 @@ Please refer to the [Changelog][action-pack] for detailed changes.
     `RedirectBackError`.
     ([Pull Request](https://github.com/rails/rails/pull/22506))
 
+*   `ActionDispatch::IntegrationTest` and `ActionController::TestCase` deprecate positional arguments in favor of
+    keyword arguments. ([Pull Request](https://github.com/rails/rails/pull/18323))
+
 ### Notable changes
 
 *   Added `ActionController::Renderer` to render arbitrary templates