diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index bc56a0b..37e2a73 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -12,7 +12,7 @@ jobs:
     - name: Set up Ruby 2.6
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 2.6.x
+        ruby-version: 2.6.6
     - name: Build and test with Rake
       run: |
         gem install bundler