diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 70cedfd..56157fd 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: macos-latest
     strategy:
       matrix:
-        ruby: [ '2.6.x', '2.5.x', '2.4.x' ]
+        ruby: [ '2.7.x', '2.6.x', '2.5.x' ]
     steps:
     - uses: actions/checkout@master
     - name: Set up Ruby
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 8d46107..e06a1dc 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: [ '2.6.x', '2.5.x', '2.4.x' ]
+        ruby: [ '2.7.x', '2.6.x', '2.5.x' ]
     steps:
     - uses: actions/checkout@master
     - name: Set up Ruby