diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ecf2635..b3ba81d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
 
     strategy:
       matrix:
-        ruby: ['3.4', '3.3', '3.2', '3.1']
+        ruby: ['4.0', '3.4', '3.3', '3.2', '3.1']
     env:
       BUNDLE_WITH: 'development_common development_test'
       BUNDLE_WITHOUT: 'development_lint development_local'