diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9622141..b9c640c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [6.0.0]
+### Changed
+- Make Data type-parameter optional in JsonRpcError ([#102](https://github.com/MetaMask/rpc-errors/pull/102))
+
+### Fixed
+- **BREAKING**: `undefined` is now not recognized as valid JSON value
+  - Update dependency `@metamask/utils` from `^5.0.0` to `^8.0.0` ([#101](https://github.com/MetaMask/rpc-errors/pull/101))
+
 ## [5.1.1]
 ### Fixed
 - Allow passing unknown values as cause ([#91](https://github.com/MetaMask/rpc-errors/pull/91))
@@ -114,7 +122,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `serializeError`
   - If the object passed to the function has a `.message` property, it will preferred over the `.message` property of the fallback error when creating the returned serialized error object
 
-[Unreleased]: https://github.com/MetaMask/rpc-errors/compare/v5.1.1...HEAD
+[Unreleased]: https://github.com/MetaMask/rpc-errors/compare/v6.0.0...HEAD
+[6.0.0]: https://github.com/MetaMask/rpc-errors/compare/v5.1.1...v6.0.0
 [5.1.1]: https://github.com/MetaMask/rpc-errors/compare/v5.1.0...v5.1.1
 [5.1.0]: https://github.com/MetaMask/rpc-errors/compare/v5.0.0...v5.1.0
 [5.0.0]: https://github.com/MetaMask/rpc-errors/compare/v4.0.3...v5.0.0
diff --git a/package.json b/package.json
index a39d713..22d12e5 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@metamask/rpc-errors",
-  "version": "5.1.1",
+  "version": "6.0.0",
   "description": "Ethereum RPC and Provider errors.",
   "keywords": [
     "rpc",