diff --git a/.github/.release-please-manifest.json b/.github/.release-please-manifest.json
index f1c8ae5..f9897f7 100644
--- a/.github/.release-please-manifest.json
+++ b/.github/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "3.9.0"
+  ".": "3.9.1"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed25543..0978203 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,13 @@
 
 This file contains all the latest changes and updates to Apia.
 
+## [3.9.1](https://github.com/apiaframework/apia/compare/v3.9.0...v3.9.1) (2025-10-22)
+
+
+### Bug Fixes
+
+* **cors:** lowercase cors headers for rack 3 compatibility ([#42](https://github.com/apiaframework/apia/issues/42)) ([859907a](https://github.com/apiaframework/apia/commit/859907a47a719776d215115208f1368009bf7654))
+
 ## [3.9.0](https://github.com/apiaframework/apia/compare/v3.8.0...v3.9.0) (2025-10-17)
 
 
diff --git a/lib/apia/version.rb b/lib/apia/version.rb
index ad1692b..25c0a80 100644
--- a/lib/apia/version.rb
+++ b/lib/apia/version.rb
@@ -2,6 +2,6 @@
 
 module Apia
 
-  VERSION = '3.9.0'
+  VERSION = '3.9.1'
 
 end