diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3038fb5..973f2a2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,14 @@
 
 This project adheres to semantic versioning.
 
+## 0.4.0 (2023-05-16)
+
+Adds supports for convenient "strict" pattern matching without access to member values, denoted by an "X" suffix.
+
+Adds a first-class, low-level `is` primitive for refining foreign data to a known sum member.
+
+Fixes reference equality of deserialized nullary sums.
+
 ## 0.3.2 (2023-03-23)
 
 Fixes nullary equality checks in Jest and others that compare the reference equality of functions.
diff --git a/package.json b/package.json
index fb7111b..a9b0431 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@unsplash/sum-types",
   "description": "Safe, ergonomic, non-generic sum types in TypeScript.",
-  "version": "0.3.2",
+  "version": "0.4.0",
   "license": "MIT",
   "author": "Unsplash",
   "repository": {