diff --git a/.github/workflows/dotnet.yml b/.github/workflows/dotnet.yml
new file mode 100644
index 0000000..2032a49
--- /dev/null
+++ b/.github/workflows/dotnet.yml
@@ -0,0 +1,41 @@
+name: .NET
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build:
+
+    runs-on: ${{ matrix.dotnet.os }}-latest
+
+    strategy:
+      matrix:
+        dotnet: [
+          { os: 'windows', version: '2', tfm: 'net20' },
+          { os: 'windows', version: '4', tfm: 'net40' },
+          { os: 'ubuntu',  version: '6', tfm: 'net6.0' },
+          { os: 'ubuntu',  version: '8', tfm: 'net8.0' },
+      ]
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Setup .NET
+      if: endsWith(matrix.dotnet.tfm, '.0') # only for .NET core
+      uses: actions/setup-dotnet@v4
+      id: stepid
+      with:
+        dotnet-version: ${{ matrix.dotnet.version }}
+      # Without global.json, tests will be executed under the latest installed version!
+    - name: Create temporary global.json
+      if: endsWith(matrix.dotnet.tfm, '.0') # only for .NET core
+      run: echo '{"sdk":{"version":"${{steps.stepid.outputs.dotnet-version}}"}}' > ./global.json
+    - name: Restore packages
+      run: dotnet restore UrlBase64/UrlBase64.csproj -p:Configuration=Release -p:TargetFrameworks="${{ matrix.dotnet.tfm }}" -p:LangVersion="latest" --verbosity normal
+    - name: Build solution
+      run: dotnet build UrlBase64/UrlBase64.csproj -p:Configuration=Release -p:TargetFrameworks="${{ matrix.dotnet.tfm }}" -p:LangVersion="latest" --verbosity normal
+    - name: Run tests
+      if: endsWith(matrix.dotnet.tfm, '.0') # only for .NET core
+      run: dotnet test -p:Configuration=Release --verbosity normal -p:TargetFrameworks="${{ matrix.dotnet.tfm }}" -p:LangVersion="latest"
diff --git a/Benchmark/Benchmark.csproj b/Benchmark/Benchmark.csproj
index acea364..9867a4d 100644
--- a/Benchmark/Benchmark.csproj
+++ b/Benchmark/Benchmark.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFrameworks>net8.0</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
diff --git a/Tests/EncodeDecode.cs b/Tests/EncodeDecode.cs
index 04df335..5476dcb 100644
--- a/Tests/EncodeDecode.cs
+++ b/Tests/EncodeDecode.cs
@@ -177,13 +177,13 @@ public void DecodeNonUrlSafeBase64()
         {
             // Decoding regular base64 input with + instead of -
             var input = "Q29udGFpbnMgYSBwbHVzIMOlw6bDn+KApuKIgsuaxpLiiIY=";
-            byte[] expected = [0x43, 0x6F, 0x6E, 0x74, 0x61, 0x69, 0x6E, 0x73, 0x20, 0x61, 0x20, 0x70, 0x6C, 0x75, 0x73, 0x20, 0xC3, 0xA5, 0xC3, 0xA6, 0xC3, 0x9F, 0xE2, 0x80, 0xA6, 0xE2, 0x88, 0x82, 0xCB, 0x9A, 0xC6, 0x92, 0xE2, 0x88, 0x86];
+            byte[] expected = new byte[] { 0x43, 0x6F, 0x6E, 0x74, 0x61, 0x69, 0x6E, 0x73, 0x20, 0x61, 0x20, 0x70, 0x6C, 0x75, 0x73, 0x20, 0xC3, 0xA5, 0xC3, 0xA6, 0xC3, 0x9F, 0xE2, 0x80, 0xA6, 0xE2, 0x88, 0x82, 0xCB, 0x9A, 0xC6, 0x92, 0xE2, 0x88, 0x86 };
             var actual = UrlBase64.Decode(input);
             CollectionAssert.AreEqual(expected, actual, "Mismatch in comparison results!");
 
             // Decoding regular base64 input with / instead of _
             input = "Q29udGFpbnMgYSBzbGFzaCDDuOKImsucw5/iiILiiJrLmsOn4oiC4omkw58=";
-            expected = [0x43, 0x6F, 0x6E, 0x74, 0x61, 0x69, 0x6E, 0x73, 0x20, 0x61, 0x20, 0x73, 0x6C, 0x61, 0x73, 0x68, 0x20, 0xC3, 0xB8, 0xE2, 0x88, 0x9A, 0xCB, 0x9C, 0xC3, 0x9F, 0xE2, 0x88, 0x82, 0xE2, 0x88, 0x9A, 0xCB, 0x9A, 0xC3, 0xA7, 0xE2, 0x88, 0x82, 0xE2, 0x89, 0xA4, 0xC3, 0x9F];
+            expected = new byte[] { 0x43, 0x6F, 0x6E, 0x74, 0x61, 0x69, 0x6E, 0x73, 0x20, 0x61, 0x20, 0x73, 0x6C, 0x61, 0x73, 0x68, 0x20, 0xC3, 0xB8, 0xE2, 0x88, 0x9A, 0xCB, 0x9C, 0xC3, 0x9F, 0xE2, 0x88, 0x82, 0xE2, 0x88, 0x9A, 0xCB, 0x9A, 0xC3, 0xA7, 0xE2, 0x88, 0x82, 0xE2, 0x89, 0xA4, 0xC3, 0x9F };
             actual = UrlBase64.Decode(input);
             CollectionAssert.AreEqual(expected, actual, "Mismatch in comparison results!");
         }
@@ -196,7 +196,7 @@ public void DecodeInvalid()
             Assert.ThrowsException<FormatException>(() => UrlBase64.Decode("!!"));
 
             // ...and this doesn't
-            UrlBase64.Decode(UrlBase64.Encode([0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF]));
+            UrlBase64.Decode(UrlBase64.Encode(new byte[] { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }));
         }
     }
 
diff --git a/UrlBase64/UrlBase64.csproj b/UrlBase64/UrlBase64.csproj
index 058f2c3..56083ce 100644
--- a/UrlBase64/UrlBase64.csproj
+++ b/UrlBase64/UrlBase64.csproj
@@ -57,7 +57,7 @@
     </None>
   </ItemGroup>
 
-  <PropertyGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
+  <PropertyGroup Condition="'$(TargetFramework)' != 'netstandard1.0' And '$(TargetFramework)' != 'net20' And '$(TargetFramework)' != 'net40'">
     <DefineConstants>$(DefineConstants);WITH_SPAN</DefineConstants>
   </PropertyGroup>
 
@@ -74,4 +74,4 @@
     <LangVersion>10.0</LangVersion>
   </PropertyGroup>
 
-</Project>
\ No newline at end of file
+</Project>