diff --git a/CHANGELOG.md b/CHANGELOG.md
index b35342b..b71f077 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,7 @@ 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).
 
-## [0.4.0] - Unreleased
+## [0.4.0] - 2024-02-06
 
 ### Added
 
@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - LearningSolver.solve no longer generates HDF5 files; use a collector instead.
+- Add `_gurobipy` suffix to all `build_model` functions; implement some `_pyomo` and `_jump` functions.
 
 ## [0.3.0] - 2023-06-08