diff --git a/package.json b/package.json
index 1255a34..192acc4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "remark-normalize-headings",
-  "version": "3.0.1",
+  "version": "4.0.0",
   "description": "remark plugin to make sure there is a single top level heading in a document by adjusting heading ranks accordingly",
   "license": "MIT",
   "keywords": [
diff --git a/readme.md b/readme.md
index 560f08f..97fe480 100644
--- a/readme.md
+++ b/readme.md
@@ -49,14 +49,14 @@ npm install remark-normalize-headings
 In Deno with [`esm.sh`][esmsh]:
 
 ```js
-import remarkNormalizeHeadings from 'https://esm.sh/remark-normalize-headings@3'
+import remarkNormalizeHeadings from 'https://esm.sh/remark-normalize-headings@4'
 ```
 
 In browsers with [`esm.sh`][esmsh]:
 
 ```html
 <script type="module">
-  import remarkNormalizeHeadings from 'https://esm.sh/remark-normalize-headings@3?bundle'
+  import remarkNormalizeHeadings from 'https://esm.sh/remark-normalize-headings@4?bundle'
 </script>
 ```