diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4ce34cd..8db1e08 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,19 @@
+## [4.0.0](https://github.com/achingbrain/uint8arrays/compare/v3.1.1...v4.0.0) (2022-10-12)
+
+
+### ⚠ BREAKING CHANGES
+
+* this module is now ESM-only
+
+### Features
+
+* convert to typescript and release as ESM-only ([#28](https://github.com/achingbrain/uint8arrays/issues/28)) ([e4c9627](https://github.com/achingbrain/uint8arrays/commit/e4c9627da195b419ee9f8c45d45931f537c5dee1))
+
+
+### Documentation
+
+* fix readme header ([803cb5f](https://github.com/achingbrain/uint8arrays/commit/803cb5fa64892451d73ca0494b1e2a57ae1ef533))
+
 ## [3.1.1](https://github.com/achingbrain/uint8arrays/compare/v3.1.0...v3.1.1) (2022-10-10)
 
 
@@ -178,6 +194,3 @@ Co-authored-by: Alex Potsides <alex@achingbrain.net>
 ### Features
 
 * add implementation ([2c849dc](https://github.com/achingbrain/uint8arrays/commit/2c849dc))
-
-
-
diff --git a/package.json b/package.json
index 2469801..63b5df4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "uint8arrays",
-  "version": "3.1.1",
+  "version": "4.0.0",
   "description": "Utility functions to make dealing with Uint8Arrays easier",
   "author": "Alex Potsides <alex@achingbrain.net>",
   "license": "Apache-2.0 OR MIT",