diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5f55e1f..41c1185 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,9 +19,9 @@ jobs:
       matrix:
         ruby-version:
         - '3.1'
-        - '3.2'
         - '3.3'
         - '3.4'
+        - '4.0'
     steps:
     - uses: actions/checkout@v6
     - name: Set up Ruby ${{ matrix.ruby-version }}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a7f54dc..068d0cd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## 3.13.0
+
+IMPROVEMENTS:
+
+- add Ruby 4.0 support
+
 ## 3.12.0 (December 4th, 2025)
 
 IMPROVEMENTS: