diff --git a/CHANGELOG.md b/CHANGELOG.md
index b52bb687e0e..17938191985 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 <!-- next-header -->
 ## [Unreleased] - ReleaseDate
 
+### Features
+
+- *(derive)* Support `#[arg(flatten)]` on `Option` types (#4211, #4350)
+
 ## [4.0.9] - 2022-10-03
 
 ### Fixes