diff --git a/CHANGES.md b/CHANGES.md
index dc28e43893d..93e8690b691 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -12,6 +12,7 @@
 ##### Fixes :wrench:
 
 - Use first geometryBuffer if no best match found in I3SNode [#12132](https://github.com/CesiumGS/cesium/pull/12132)
+- Update type definitions to allow undefined for optional parameters [#12193](https://github.com/CesiumGS/cesium/pull/12193)
 
 ### 1.121.1 - 2024-09-04