diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4dfc7e1..596f689 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,8 @@ and this project attempts to adhere to [Semantic Versioning](https://semver.org/
 
 ## [Unreleased]
 
+## [0.4.0]
+
 ### Added
 
 - An `python-nohash-requirements` input for specifying Python requirements files to install without hashing them for caching.
@@ -75,7 +77,7 @@ Initial release! 🎉
 
 - Josh Thomas <josh@joshthomas.dev> (maintainer)
 
-[unreleased]: https://github.com/westerveltco/setup-ci-action/compare/v0.3.0...HEAD
+[unreleased]: https://github.com/westerveltco/setup-ci-action/compare/v0.4.0...HEAD
 [0.1.0]: https:L//github.com/westerveltco/setup-ci-action/releases/tag/v0.1.0
 [0.1.1]: https:L//github.com/westerveltco/setup-ci-action/releases/tag/v0.1.1
 [0.1.2]: https:L//github.com/westerveltco/setup-ci-action/releases/tag/v0.1.2
@@ -83,3 +85,4 @@ Initial release! 🎉
 [0.2.1]: https://github.com/westerveltco/setup-ci-action/releases/tag/v0.2.1
 [0.2.2]: https://github.com/westerveltco/setup-ci-action/releases/tag/v0.2.2
 [0.3.0]: https://github.com/westerveltco/setup-ci-action/releases/tag/v0.3.0
+[0.4.0]: https://github.com/westerveltco/setup-ci-action/releases/tag/v0.4.0
diff --git a/VERSION b/VERSION
index 0d91a54..1d0ba9e 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.3.0
+0.4.0
diff --git a/bumpver.toml b/bumpver.toml
index 38cc67f..0146287 100644
--- a/bumpver.toml
+++ b/bumpver.toml
@@ -1,7 +1,7 @@
 [bumpver]
 commit = true
 commit_message = ":bookmark: bump version {old_version} -> {new_version}"
-current_version = "0.3.0"
+current_version = "0.4.0"
 push = false  # set to false for CI
 tag = false
 version_pattern = "MAJOR.MINOR.PATCH[PYTAGNUM]"