diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index ff64ffd195..043f5fc16f 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -5,11 +5,16 @@ on: [push, pull_request]
 jobs:
   build:
     runs-on: macos-latest
+    strategy:
+      matrix:
+        ruby: [ 2.7, 2.6, 2.5 ]
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v2
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
     - name: Install dependencies
-      run: |
-        gem install bundler --no-document
-        bundle install
+      run: bundle install
     - name: rake test
       run:  rake test
diff --git a/.github/workflows/ubuntu-rvm-with-irb.yml b/.github/workflows/ubuntu-rvm-with-irb.yml
deleted file mode 100644
index af8dbb6eed..0000000000
--- a/.github/workflows/ubuntu-rvm-with-irb.yml
+++ /dev/null
@@ -1,42 +0,0 @@
-name: ubuntu-rvm with irb
-
-on: [push, pull_request]
-
-jobs:
-  build:
-    runs-on: ubuntu-16.04
-    strategy:
-      matrix:
-        ruby: [ 'ruby-head' ]
-    steps:
-    - uses: actions/checkout@master
-    - name: Set up RVM
-      run: |
-        curl -sSL https://get.rvm.io | bash
-    - name: Set up Ruby
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        rvm install ${{ matrix.ruby }} --binary
-        rvm --default use ${{ matrix.ruby }}
-    - name: Install dependencies
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        gem install bundler --no-document
-        bundle install
-    - name: Install reline
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        rake build
-        rake install
-    - name: Download ruby/irb
-      run: |
-        git clone https://github.com/ruby/irb
-    - name: Setup ruby/irb
-      run: |
-        cd irb
-        source $HOME/.rvm/scripts/rvm
-        bundle install
-    - name: Run irb test
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        bundle exec rake test
diff --git a/.github/workflows/ubuntu-rvm-with-readline.yml b/.github/workflows/ubuntu-rvm-with-readline.yml
deleted file mode 100644
index abbdc0af53..0000000000
--- a/.github/workflows/ubuntu-rvm-with-readline.yml
+++ /dev/null
@@ -1,36 +0,0 @@
-name: ubuntu-rvm with readline
-
-on: [push, pull_request]
-
-jobs:
-  build:
-    runs-on: ubuntu-16.04
-    strategy:
-      matrix:
-        ruby: [ 'ruby-head' ]
-    steps:
-    - uses: actions/checkout@master
-    - name: Set up RVM
-      run: |
-        curl -sSL https://get.rvm.io | bash
-    - name: Set up Ruby
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        rvm install ${{ matrix.ruby }} --binary
-        rvm --default use ${{ matrix.ruby }}
-    - name: Install dependencies
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        gem install bundler --no-document
-        bundle install
-    - name: Download test readline
-      run: |
-        sh ./download-test_readline.sh
-    - name: rake test
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        bundle exec rake test
-    - name: rake ci-test
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        bundle exec rake ci-test
diff --git a/.github/workflows/ubuntu-rvm.yml b/.github/workflows/ubuntu-rvm.yml
deleted file mode 100644
index 7d17af7723..0000000000
--- a/.github/workflows/ubuntu-rvm.yml
+++ /dev/null
@@ -1,29 +0,0 @@
-name: ubuntu-rvm
-
-on: [push, pull_request]
-
-jobs:
-  build:
-    runs-on: ubuntu-16.04
-    strategy:
-      matrix:
-        ruby: [ 'ruby-head' ]
-    steps:
-    - uses: actions/checkout@master
-    - name: Set up RVM
-      run: |
-        curl -sSL https://get.rvm.io | bash
-    - name: Set up Ruby
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        rvm install ${{ matrix.ruby }} --binary
-        rvm --default use ${{ matrix.ruby }}
-    - name: Install dependencies
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        gem install bundler --no-document
-        bundle install
-    - name: rake test
-      run: |
-        source $HOME/.rvm/scripts/rvm
-        bundle exec rake test
diff --git a/.github/workflows/ubuntu-with-irb.yml b/.github/workflows/ubuntu-with-irb.yml
new file mode 100644
index 0000000000..55f21d75c7
--- /dev/null
+++ b/.github/workflows/ubuntu-with-irb.yml
@@ -0,0 +1,31 @@
+name: ubuntu with irb
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby: [ 'ruby-head' ]
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+    - name: Install dependencies
+      run: bundle install
+    - name: Install reline
+      run: |
+        rake build
+        rake install
+    - name: Download ruby/irb
+      run: |
+        git clone https://github.com/ruby/irb
+    - name: Setup ruby/irb
+      run: |
+        cd irb
+        bundle install
+    - name: Run irb test
+      run: bundle exec rake test
diff --git a/.github/workflows/ubuntu-with-readline.yml b/.github/workflows/ubuntu-with-readline.yml
new file mode 100644
index 0000000000..9fe2748390
--- /dev/null
+++ b/.github/workflows/ubuntu-with-readline.yml
@@ -0,0 +1,24 @@
+name: ubuntu with readline
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby: [ 'ruby-head' ]
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+    - name: Install dependencies
+      run: bundle install
+    - name: Download test readline
+      run: sh ./download-test_readline.sh
+    - name: rake test
+      run: bundle exec rake test
+    - name: rake ci-test
+      run: bundle exec rake ci-test
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 39101f20ed..5828ef83e5 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -7,16 +7,14 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: [ '2.7.x', '2.6.x', '2.5.x' ]
+        ruby: [ 2.7, 2.6, 2.5 ]
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v2
     - name: Set up Ruby
-      uses: actions/setup-ruby@v1
+      uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
     - name: Install dependencies
-      run: |
-        gem install bundler --no-document
-        bundle install
+      run: bundle install
     - name: rake test
       run:  rake test
diff --git a/.github/workflows/windows-with-readline.yml b/.github/workflows/windows-with-readline.yml
index e2aea5f299..a8b889a699 100644
--- a/.github/workflows/windows-with-readline.yml
+++ b/.github/workflows/windows-with-readline.yml
@@ -8,18 +8,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [ '9.9.x' ]
+        ruby: [ mingw, mswin ]
     steps:
-      - uses: actions/checkout@master
+      - uses: actions/checkout@v2
       - name: Set up Ruby
-        uses: MSP-Greg/actions-ruby@master
+        uses: MSP-Greg/actions-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
-      - name: Install dependencies
-        if: matrix.ruby != '9.9.x'
-        run: |
-          gem install bundler --no-document --conservative
-          bundle install
       - name: Download test readline
         run:  ./download-test_readline.ps1
       - name: rake test
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 221049eed5..3012019787 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -8,17 +8,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [ '9.9.x', '2.7.x', '2.6.x', '2.5.x' ]
+        ruby: [ 2.7, 2.6, 2.5 ]
     steps:
-      - uses: actions/checkout@master
+      - uses: actions/checkout@v2
       - name: Set up Ruby
-        uses: MSP-Greg/actions-ruby@master
+        uses: MSP-Greg/actions-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
-      - name: Install dependencies
-        if: matrix.ruby != '9.9.x'
-        run: |
-          gem install bundler --no-document --conservative
-          bundle install
       - name: rake test
         run:  rake test