diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 45995b9..ff703a0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -25,6 +25,6 @@ jobs:
       - uses: actions/checkout@v2
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7
+          ruby-version: 2.5
       - run: bundle install
       - run: bundle exec rubocop