diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index be7bef7b..82a1b896 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -95,4 +95,4 @@ jobs:
       - run: npm --prefix assets run check
       - run: npm --prefix assets test
 
-      - uses: mbta/actions/dialyzer@v2
+      - uses: mbta/actions/dialyzer@v2.21