diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8027ec30..e84fa9c1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -7,15 +7,7 @@ jobs:
     name: Build (Windows)
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@v2
-    - name: Setup .NET Core 3.1
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '3.1.x'
-    - name: Setup .NET 6.0
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '6.0.x'
+    - uses: actions/checkout@v4
     - name: Setup .NET 8.0
       uses: actions/setup-dotnet@v1
       with:
@@ -37,15 +29,7 @@ jobs:
     name: Build (Linux)
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
-    - name: Setup .NET Core 3.1
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '3.1.x'
-    - name: Setup .NET 6.0
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '6.0.x'
+    - uses: actions/checkout@v4
     - name: Setup .NET 8.0
       uses: actions/setup-dotnet@v1
       with:
@@ -67,15 +51,7 @@ jobs:
     name: Build (macOS)
     runs-on: macos-latest
     steps:
-    - uses: actions/checkout@v2
-    - name: Setup .NET Core 3.1
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '3.1.x'
-    - name: Setup .NET 6.0
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '6.0.x'
+    - uses: actions/checkout@v4
     - name: Setup .NET 8.0
       uses: actions/setup-dotnet@v1
       with:
@@ -98,7 +74,7 @@ jobs:
     runs-on: windows-latest
     needs: build-windows
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Download packages
       uses: actions/download-artifact@v2
       with:
@@ -107,12 +83,6 @@ jobs:
     - name: Test (net462)
       run: ./make.ps1 -frameworks net462 test-all
       shell: pwsh
-    - name: Test (netcoreapp3.1)
-      run: ./make.ps1 -frameworks netcoreapp3.1 test-all
-      shell: pwsh
-    - name: Test (net6.0)
-      run: ./make.ps1 -frameworks net6.0 test-all
-      shell: pwsh
     - name: Test (net8.0)
       run: ./make.ps1 -frameworks net8.0 test-all
       shell: pwsh
@@ -125,7 +95,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: build-ubuntu
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Download packages
       uses: actions/download-artifact@v2
       with:
@@ -134,12 +104,6 @@ jobs:
     - name: Test (net462)
       run: ./make.ps1 -frameworks net462 test-all
       shell: pwsh
-    - name: Test (netcoreapp3.1)
-      run: ./make.ps1 -frameworks netcoreapp3.1 test-all
-      shell: pwsh
-    - name: Test (net6.0)
-      run: ./make.ps1 -frameworks net6.0 test-all
-      shell: pwsh
     - name: Test (net8.0)
       run: ./make.ps1 -frameworks net8.0 test-all
       shell: pwsh
@@ -152,7 +116,7 @@ jobs:
     runs-on: macos-latest
     needs: build-macos
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Download packages
       uses: actions/download-artifact@v2
       with:
@@ -161,12 +125,6 @@ jobs:
     - name: Test (net462)
       run: ./make.ps1 -frameworks net462 test-all
       shell: pwsh
-    - name: Test (netcoreapp3.1)
-      run: ./make.ps1 -frameworks netcoreapp3.1 test-all
-      shell: pwsh
-    - name: Test (net6.0)
-      run: ./make.ps1 -frameworks net6.0 test-all
-      shell: pwsh
     - name: Test (net8.0)
       run: ./make.ps1 -frameworks net8.0 test-all
       shell: pwsh