diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 8913685..ee07e88 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -13,7 +13,7 @@ jobs:
 
       - uses: aiken-lang/setup-aiken@v0.1.0
         with:
-          version: v1
+          version: v1.0.20-alpha
 
       - run: aiken fmt --check
       - run: aiken check -D