diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7ec5ca2..8e98667 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+
+## [4.0.0] - 2020-09-11
 ### Removed
 - Removed obsolete support for `country_name`
 - Removed dependency on `league/iso3166`
diff --git a/composer.json b/composer.json
index e806347..53b44c9 100644
--- a/composer.json
+++ b/composer.json
@@ -3,7 +3,7 @@
   "description": "MultiSafepay PHP SDK",
   "type": "library",
   "license": "MIT",
-  "version": "3.0.2",
+  "version": "4.0.0",
   "require": {
     "php": "^7.1",
     "ext-json": "*",
diff --git a/src/Util/Version.php b/src/Util/Version.php
index 8f6db8b..8df369d 100644
--- a/src/Util/Version.php
+++ b/src/Util/Version.php
@@ -17,7 +17,7 @@
  */
 class Version
 {
-    const SDK_VERSION = '3.0.2';
+    const SDK_VERSION = '4.0.0';
 
     /**
      * @var Version