diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3b0a52c..586c589 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,16 @@
 # Changelog
 
+## [6.0.0](https://github.com/mljs/conrec/compare/v5.0.3...v6.0.0) (2026-04-21)
+
+
+### ⚠ BREAKING CHANGES
+
+* package is now ESM-only; consumers using require() must migrate to import, or run Node.js ≥ 20.19 (or ≥ 22.12 / any 24.x), which supports require() of ESM.
+
+### Features
+
+* migrate package to ESM ([02f4ca3](https://github.com/mljs/conrec/commit/02f4ca3e822134c045600dba8602104816b1a9de))
+
 ## [5.0.3](https://github.com/mljs/conrec/compare/v5.0.2...v5.0.3) (2024-09-13)
 
 
diff --git a/package.json b/package.json
index b9864d0..4e75c4b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ml-conrec",
-  "version": "5.0.3",
+  "version": "6.0.0",
   "description": "JavaScript implementation of the CONREC contouring algorithm",
   "type": "module",
   "exports": {