diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5eaab083..e5ea4f99 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+- Implement `From<MaybeUndefined<T>> for Option<Option<T>>`. [#599](https://github.com/async-graphql/async-graphql/issues/599)
+
 ## [2.9.10] 2021-08-05
 
 - Change `GraphQLPlaygroundConfig::with_setting` to accept `impl Into<Value>` [#583](https://github.com/async-graphql/async-graphql/issues/583)