diff --git a/package.json b/package.json
index 0bd5d87de2..0cec2429c3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ckeditor/ckeditor5-build-classic",
-  "version": "0.4.0",
+  "version": "1.0.0-alpha.1",
   "description": "CKEditor 5 classic editor build.",
   "keywords": [
     "ckeditor5",