diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1e5af91..3e00b87 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,6 +22,7 @@ jobs:
       matrix:
         go:
           - 1.22.x
+          - 1.21.x
           - 1.18.x
     name: Test with Go v${{ matrix.go }}
     steps: