diff --git a/CHANGELOG.md b/CHANGELOG.md
index bfee221..f79bdc0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,16 @@
+# [4.0.0](https://github.com/wasdk/wasmparser/compare/v3.3.1...v4.0.0) (2020-11-03)
+
+
+### Bug Fixes
+
+* both members of IFunctionBodyOffset are mandatory numbers ([7383b87](https://github.com/wasdk/wasmparser/commit/7383b87960e09844c094588424bc0acb3076838c))
+
+
+### BREAKING CHANGES
+
+* the `start` and `end` fields of `IFunctionBodyOffset`
+were optional members before.
+
 ## [3.3.1](https://github.com/wasdk/wasmparser/compare/v3.3.0...v3.3.1) (2020-10-27)
 
 
diff --git a/package-lock.json b/package-lock.json
index 7f99416..09ac63b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "wasmparser",
-  "version": "3.3.1",
+  "version": "4.0.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 620d071..ce45d8d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "wasmparser",
-  "version": "3.3.1",
+  "version": "4.0.0",
   "description": "Binary WebAssembly file parser.",
   "main": "dist/cjs/index.js",
   "module": "dist/esm/index.js",