diff --git a/package.json b/package.json
index c276f53..93c78e7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "monadical",
-  "version": "3.4.0",
+  "version": "4.0.0",
   "description": "A set of monadic data types",
   "scripts": {
     "build": "scripts/build",