diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 7f4e661..ec88cb5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -13,7 +13,7 @@ jobs:
     strategy:
       matrix:
         ruby: ['2.6', '2.4']
-        redmine: ['4.1-stable', 'master']
+        redmine: ['4.0-stable', '4.1-stable', 'master']
         db: ['postgres', 'mysql']
       fail-fast: false