diff --git a/CHANGELOG.md b/CHANGELOG.md
index bf305fd..928960f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,12 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 
+## v0.4.0 (2024-07-09)
+
+### Feat
+
+- switch from setup.cfg to pyproject.toml + hatchling
+
 ## 0.3.6 (2023-06-01)
 
 * Replace ``setup.py`` contents with ``setup.cfg``.
diff --git a/pyproject.toml b/pyproject.toml
index 44140cb..cec10d3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "rattail_cognitive"
-version = "0.3.6"
+version = "0.4.0"
 description = "Hardware Interfaces for Cognitive Devices"
 readme = "README.txt"
 authors = [{name = "Lance Edgar", email = "lance@edbob.org"}]