diff --git a/CHANGELOG.md b/CHANGELOG.md
index 800aa03..ddafd4d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,11 +4,11 @@ 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
+## 0.4.0 - 2022-06-13
 
 ### Changed
 
-- `--avoid-type-null` is now deprecated, and acts as an alias for `--use_nullable_for_merge_patch`. This flag now generates complete OpenAPI 3.0-compatible MergePatch types using a clever hack based on `nullable: true` and `oneOf:`. It also now sets the file version number to `openapi: 3.0.0` when used, because 3.1 does not support `nullable: true`.
+- `--avoid-type-null` is now deprecated, and acts as an alias for `--use-nullable-for-merge-patch`. This flag now generates complete OpenAPI 3.0-compatible MergePatch types using a clever hack based on `nullable: true` and `oneOf:`. It also now sets the file version number to `openapi: 3.0.0` when used, because 3.1 does not support `nullable: true`.
 
 ## 0.3.0 - 2022-06-13
 
diff --git a/Cargo.lock b/Cargo.lock
index e308305..d7a0c50 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -248,7 +248,7 @@ checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
 
 [[package]]
 name = "openapi-interfaces"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "anyhow",
  "codespan-reporting",
diff --git a/Cargo.toml b/Cargo.toml
index 6825244..7bd6885 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "openapi-interfaces"
-version = "0.3.0"
+version = "0.4.0"
 authors = ["Eric Kidd <git@randomhacks.net>"]
 edition = "2018"