diff --git a/CHANGELOG.md b/CHANGELOG.md
index b0f4057..428dd5f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -57,7 +57,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Smoke test and really build to **Travis CI**.
 - Labels of `npm`, `coverage`, `travis`.
 
-[unreleased]: https://github.com/snatvb/monad-maniac/compare/v0.3.0...develop
+[unreleased]: https://github.com/snatvb/monad-maniac/compare/v0.4.0...develop
+[0.4.0]: https://github.com/snatvb/monad-maniac/compare/v0.3.0...v0.4.0
 [0.3.0]: https://github.com/snatvb/monad-maniac/compare/v0.2.0...v0.3.0
 [0.2.0]: https://github.com/snatvb/monad-maniac/compare/v0.1.0...v0.2.0
 [0.1.0]: https://github.com/snatvb/monad-maniac/compare/v0.0.1...v0.1.0
\ No newline at end of file
diff --git a/README.md b/README.md
index dd095ca..dfe23e1 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,7 @@
 - [Documentation](http://mm.snatvb.ru)
   * [Maybe](http://mm.snatvb.ru/modules/_maybe_.html)
   * [Either](http://mm.snatvb.ru/modules/_either_.html)
+  * [IO](http://mm.snatvb.ru/modules/_io_.html)
 - [Github](https://github.com/snatvb/monad-maniac)
 - [NPM](https://www.npmjs.com/package/monad-maniac)
 
diff --git a/package.json b/package.json
index 275dfc7..4d7b674 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "monad-maniac",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "monads with right rules",
   "scripts": {
     "ts:cjs": "yarn tsc -p ts/cjs.tsconfig.json",
diff --git a/scripts/build-docs b/scripts/build-docs
old mode 100644
new mode 100755