diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5261d22..bbc3020 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [8, 11, 17]
+        java: [8, 11, 17, 21]
         scala: [2.13.14]
     runs-on: ubuntu-latest
     steps: