diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index ada7355..e6f8775 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "3.1.0"
+  ".": "4.0.0"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8abf651..e335b03 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,33 @@
 # Changelog
 
+## [4.0.0](https://github.com/ChainSafe/zapi/compare/zapi-v3.1.0...zapi-v4.0.0) (2026-07-29)
+
+
+### ⚠ BREAKING CHANGES
+
+* manage external buffer lifetime ([#66](https://github.com/ChainSafe/zapi/issues/66))
+* require writable external buffer storage ([#58](https://github.com/ChainSafe/zapi/issues/58))
+
+### Bug Fixes
+
+* **dsl:** support class pointer arguments ([#50](https://github.com/ChainSafe/zapi/issues/50)) ([9dd2111](https://github.com/ChainSafe/zapi/commit/9dd211167c4774c5a79e3d6fd360c22adca0a138))
+* harden N-API boundary against JS-triggerable memory bugs ([#60](https://github.com/ChainSafe/zapi/issues/60)) ([fff76f3](https://github.com/ChainSafe/zapi/commit/fff76f32b9b9b6e92991ab8045fe7562fa3a4552))
+* manage external buffer lifetime ([#66](https://github.com/ChainSafe/zapi/issues/66)) ([d134a6a](https://github.com/ChainSafe/zapi/commit/d134a6a5bc6f03583de28ef712d8df2ca834c83d))
+* **napi:** receive raw pointer out parameters ([#57](https://github.com/ChainSafe/zapi/issues/57)) ([fde4a9a](https://github.com/ChainSafe/zapi/commit/fde4a9a10eee3fb270d26547137e975ed3df10b9))
+* remove redundant platform check from musl detection ([#64](https://github.com/ChainSafe/zapi/issues/64)) ([0d4829c](https://github.com/ChainSafe/zapi/commit/0d4829c2f5847a14fff60ff70a6cdf4d65cb8a4e))
+* require writable external buffer storage ([#58](https://github.com/ChainSafe/zapi/issues/58)) ([8fd898f](https://github.com/ChainSafe/zapi/commit/8fd898fc9d9edcd368e25f3fe3513915dd116461))
+* restore registerDecls on Zig 0.16 ([#59](https://github.com/ChainSafe/zapi/issues/59)) ([7f3af3e](https://github.com/ChainSafe/zapi/commit/7f3af3e7f5710892d441c80593adb35d028a93de))
+
+
+### Code Refactoring
+
+* **js:** unify env lifecycle refcounting ([#53](https://github.com/ChainSafe/zapi/issues/53)) ([d3d5056](https://github.com/ChainSafe/zapi/commit/d3d50565382e30580def5c71f48f310fdf6246fa))
+
+
+### Miscellaneous Chores
+
+* define changelog sections for release-please ([#54](https://github.com/ChainSafe/zapi/issues/54)) ([1c5e7b4](https://github.com/ChainSafe/zapi/commit/1c5e7b4c4e668ce425d0877212d58c88efa8525a))
+
 ## [3.1.0](https://github.com/ChainSafe/zapi/compare/zapi-v3.0.0...zapi-v3.1.0) (2026-07-10)
 
 
diff --git a/build.zig.zon b/build.zig.zon
index 14ef97a..ba72e33 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -1,6 +1,6 @@
 .{
     .name = .zapi,
-    .version = "3.1.0", // x-release-please-version
+    .version = "4.0.0", // x-release-please-version
     .fingerprint = 0x77829ef951b38aac,
     .minimum_zig_version = "0.16.0",
     .paths = .{ "build.zig", "build.zig.zon", "src", "include" },
diff --git a/package.json b/package.json
index 1c9988c..c0d6b04 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
 	"name": "@chainsafe/zapi",
 	"license": "MIT",
-	"version": "3.1.0",
+	"version": "4.0.0",
 	"description": "A tool for managing and publishing Zig NAPI packages.",
 	"homepage": "https://github.com/ChainSafe/zapi/tree/main/#readme",
 	"repository": {