diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58e8b61..ae07508 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 4.0.0
+
+- Updated `AuthSessionDelegate` method for updating error to take a completion to support async updates [#229](https://github.com/google/GTMAppAuth/pull/229)
+
 # 3.0.0
 
 - GTMAppAuth has been translated from Objective-C to Swift. ([#190](https://github.com/google/GTMAppAuth/pull/190))
diff --git a/GTMAppAuth.podspec b/GTMAppAuth.podspec
index 8e1f727..ab9a9ce 100644
--- a/GTMAppAuth.podspec
+++ b/GTMAppAuth.podspec
@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name          = 'GTMAppAuth'
-  s.version       = '3.0.0'
+  s.version       = '4.0.0'
   s.swift_version = '4.0'
   s.summary       = 'Authorize GTM Session Fetcher requests with AppAuth via GTMAppAuth'