diff --git a/CHANGELOG.md b/CHANGELOG.md
index e5a30eaf..cf1c6b2f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0),
 
 ## Unreleased
 
+## [0.4.21](https://github.com/Nullus157/async-compression/compare/v0.4.20...v0.4.21) - 2025-03-15
+
+### Fixed
+
+- When flate encoding, do not mark internal state as flushed if it ran out of buffer space.
+- Add debug assertion in `produce` method to check buffer capacity in implementations for `BufWriter`.
+
 ## [0.4.20](https://github.com/Nullus157/async-compression/compare/v0.4.19...v0.4.20) - 2025-02-28
 
 ### Added
diff --git a/Cargo.toml b/Cargo.toml
index a23e100e..58d3e03a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "async-compression"
-version = "0.4.20"
+version = "0.4.21"
 authors = ["Wim Looman <wim@nemo157.com>", "Allen Bui <fairingrey@gmail.com>"]
 edition = "2018"
 resolver = "2"