diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index c3244b8426..5db1ec26c0 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -7,7 +7,11 @@ A new header is inserted each time a *tag* is created.
 
 ## v1.21.1
 
-- engine: allow both screen-space refraction and screen-space reflections on the same object [⚠️ **Material breakage**].
+- engine: Allow both screen-space refraction and screen-space reflections on the same object [⚠️ **Material breakage**].
+- engine: Optimizations for screen-space reflections.
+- engine: Remove `Viewport::scale()` [⚠️ **API Change**].
+- engine: Fix 12x overallocation of memory in `MorphTargetBuffer`.
+- Metal: Fix validation error when reading from default `SwapChain`.
 
 ## v1.21.0