diff --git a/docs/RELEASE_NOTES.md b/docs/RELEASE_NOTES.md
index 7f656526..91c6ddb3 100644
--- a/docs/RELEASE_NOTES.md
+++ b/docs/RELEASE_NOTES.md
@@ -1,3 +1,9 @@
+#### 4.0.0-beta04 - May 10, 2026
+
+- improve: surface schema description as XmlDoc on generated object and enum types (#419)
+- improve: add `<returns>` XmlDoc tag for operation response descriptions (#420)
+- test: add direct unit tests for XmlDoc module (+32 tests, 357→389) (#422)
+
 #### 4.0.0-beta03 - May 1, 2026
 
 - fix: handle `DateOnly` in `toParam` and `toQueryParams` for correct serialization (#393)