diff --git a/package.json b/package.json
index 73d9c45..7c1ecb4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "xastscript",
-  "version": "3.1.1",
+  "version": "4.0.0",
   "description": "xast utility to create trees",
   "license": "MIT",
   "keywords": [
diff --git a/readme.md b/readme.md
index 7527872..58ecac1 100644
--- a/readme.md
+++ b/readme.md
@@ -57,14 +57,14 @@ npm install xastscript
 In Deno with [`esm.sh`][esmsh]:
 
 ```js
-import {x} from 'https://esm.sh/xastscript@3'
+import {x} from 'https://esm.sh/xastscript@4'
 ```
 
 In browsers with [`esm.sh`][esmsh]:
 
 ```html
 <script type="module">
-  import {x} from 'https://esm.sh/xastscript@3?bundle'
+  import {x} from 'https://esm.sh/xastscript@4?bundle'
 </script>
 ```