diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4125735c..48c74c1c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## Version 4.0.0
+- Support Retention Messaging API [https://github.com/apple/app-store-server-library-java/pull/198]
+  - This changes internal details of BaseAppStoreServerAPIClient, which is a breaking change for subclassing clients
+- Incorporate changes for App Store Server API v1.17 [https://github.com/apple/app-store-server-library-java/pull/201] from @riyazpanjwani
+- Add a new VerificationStatus case for retryable OCSP network failures [https://github.com/apple/app-store-server-library-java/pull/204]
+- Incorporate changes for App Store Server API v1.18 [https://github.com/apple/app-store-server-library-java/pull/209] from @izanger
+  - This changes OfferType's case SUBSCRIPTION_OFFER_CODE to OFFER_CODE, which is a breaking change
+
 ## Version 3.6.0
 - Testing new Maven Central deployment process [https://github.com/apple/app-store-server-library-java/pull/185]
 
diff --git a/README.md b/README.md
index 7188e749..6a8db65c 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ The Java server library for the [App Store Server API](https://developer.apple.c
 
 ### Gradle
 ```groovy
-implementation 'com.apple.itunes.storekit:app-store-server-library:3.6.0'
+implementation 'com.apple.itunes.storekit:app-store-server-library:4.0.0'
 
 ```
 
@@ -24,7 +24,7 @@ implementation 'com.apple.itunes.storekit:app-store-server-library:3.6.0'
 <dependency>
     <groupId>com.apple.itunes.storekit</groupId>
     <artifactId>app-store-server-library</artifactId>
-    <version>3.6.0</version>
+    <version>4.0.0</version>
 </dependency>
 ```
 
diff --git a/gradle.properties b/gradle.properties
index 38927612..b0f3f48e 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,2 +1,2 @@
-version=3.6.0
+version=4.0.0
 group=com.apple.itunes.storekit
diff --git a/src/main/java/com/apple/itunes/storekit/client/BaseAppStoreServerAPIClient.java b/src/main/java/com/apple/itunes/storekit/client/BaseAppStoreServerAPIClient.java
index fc3e458c..ba4c36ea 100644
--- a/src/main/java/com/apple/itunes/storekit/client/BaseAppStoreServerAPIClient.java
+++ b/src/main/java/com/apple/itunes/storekit/client/BaseAppStoreServerAPIClient.java
@@ -49,7 +49,7 @@ public abstract class BaseAppStoreServerAPIClient {
     private static final String PRODUCTION_URL = "https://api.storekit.itunes.apple.com";
     private static final String SANDBOX_URL = "https://api.storekit-sandbox.itunes.apple.com";
     private static final String LOCAL_TESTING_URL = "https://local-testing-base-url";
-    private static final String USER_AGENT = "app-store-server-library/java/3.6.0";
+    private static final String USER_AGENT = "app-store-server-library/java/4.0.0";
     private static final String JSON = "application/json; charset=utf-8";
     private static final String PNG = "image/png";