diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d3272dee71..cfb5c13454 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -71,7 +71,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        dotnet: [ '3.1.x' ]
+        dotnet: [ '8.0.x' ]
     env:
       DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
       DOTNET_CLI_TELEMETRY_OPTOUT: 1
diff --git a/csharp/sbe-benchmarks/sbe-benchmarks.csproj b/csharp/sbe-benchmarks/sbe-benchmarks.csproj
index 8d10e86c4f..3324fe01c2 100644
--- a/csharp/sbe-benchmarks/sbe-benchmarks.csproj
+++ b/csharp/sbe-benchmarks/sbe-benchmarks.csproj
@@ -1,11 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;netcoreapp3.1</TargetFrameworks>
+    <TargetFramework>net8.0</TargetFramework>
     <RootNamespace>Org.SbeTool.Sbe.Benchmarks</RootNamespace>
     <AssemblyName>sbe-benchmarks</AssemblyName>
     <OutputTypeEx>exe</OutputTypeEx>
-    <Copyright>Copyright (C) Bill Segall 2018, MarketFactory Inc 2017, Adaptive 2014. All rights reserved.</Copyright>
+    <Copyright>Copyright (C) Bill Segall 2018, MarketFactory Inc 2017, Adaptive 2014-2024. All rights reserved.</Copyright>
     <Product>SBE</Product>
     <OutputType>Exe</OutputType>
   </PropertyGroup>
@@ -16,9 +16,8 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="BenchmarkDotNet" Version="0.12.1" />
-    <PackageReference Include="BenchmarkDotNet.Annotations" Version="0.12.1" />
-    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-preview.2" PrivateAssets="All" />
+    <PackageReference Include="BenchmarkDotNet" Version="0.13.12" />
+    <PackageReference Include="BenchmarkDotNet.Annotations" Version="0.13.12" />
   </ItemGroup>
 
 </Project>
diff --git a/csharp/sbe-dll/sbe-dll.csproj b/csharp/sbe-dll/sbe-dll.csproj
index 2c369ba21e..747306310d 100644
--- a/csharp/sbe-dll/sbe-dll.csproj
+++ b/csharp/sbe-dll/sbe-dll.csproj
@@ -1,11 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net45;netstandard2.0</TargetFrameworks>
+    <TargetFramework>netstandard2.0</TargetFramework>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
     <AssemblyName>SBE</AssemblyName>
     <RootNamespace>Org.SbeTool.Sbe.Dll</RootNamespace>
     <Product>Org.SbeTool.Sbe.Dll</Product>
-    <Copyright>Copyright (C) Bill Segall 2018-2021, MarketFactory Inc 2017, Adaptive 2014. All rights reserved.</Copyright>
+    <Copyright>Copyright (C) Bill Segall 2018-2021, MarketFactory Inc 2017, Adaptive 2014-2024. All rights reserved.</Copyright>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <Authors>Bill Segall, MarketFactory Inc, Adaptive Consulting</Authors>
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
@@ -37,10 +37,6 @@
     </None>
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net45' ">
-    <Reference Include="System.Runtime" />
-  </ItemGroup>
-
   <ItemGroup>
     <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-preview.2" PrivateAssets="All" />
     <PackageReference Include="System.Memory" Version="4.5.3" />
diff --git a/csharp/sbe-generated/sbe-generated.csproj b/csharp/sbe-generated/sbe-generated.csproj
index 806168d7d5..f5b42e2355 100644
--- a/csharp/sbe-generated/sbe-generated.csproj
+++ b/csharp/sbe-generated/sbe-generated.csproj
@@ -1,26 +1,23 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net45;netstandard2.0</TargetFrameworks>
+    <TargetFramework>net8.0</TargetFramework>
     <RootNamespace>Org.SbeTool.Sbe.Generated</RootNamespace>
     <AssemblyName>Org.SbeTool.Sbe.Generated</AssemblyName>
-    <Copyright>Copyright (C) Bill Segall 2018, MarketFactory Inc 2017, Adaptive 2014. All rights reserved.</Copyright>
+    <Copyright>Copyright (C) Bill Segall 2018, MarketFactory Inc 2017, Adaptive 2014-2024. All rights reserved.</Copyright>
+    <LangVersion>9</LangVersion>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
-    <DefineConstants>TRACE,SBE_ENABLE_PRECEDENCE_CHECKS</DefineConstants>
+    <DefineConstants>TRACE;SBE_ENABLE_PRECEDENCE_CHECKS</DefineConstants>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
-    <DefineConstants>TRACE,SBE_ENABLE_PRECEDENCE_CHECKS</DefineConstants>
+    <DefineConstants>TRACE;SBE_ENABLE_PRECEDENCE_CHECKS</DefineConstants>
   </PropertyGroup>
 
   <ItemGroup>
     <ProjectReference Include="..\sbe-dll\sbe-dll.csproj" />
   </ItemGroup>
 
-  <ItemGroup>
-    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-preview.2" PrivateAssets="All" />
-  </ItemGroup>
-
 </Project>
diff --git a/csharp/sbe-samples-car/sbe-samples-car.csproj b/csharp/sbe-samples-car/sbe-samples-car.csproj
index 8ee29c2329..cf39c0d9ef 100644
--- a/csharp/sbe-samples-car/sbe-samples-car.csproj
+++ b/csharp/sbe-samples-car/sbe-samples-car.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net45;netcoreapp3.1</TargetFrameworks>
+    <TargetFramework>net8.0</TargetFramework>
     <OutputType>exe</OutputType>
     <RootNamespace>Org.SbeTool.Sbe.Example.Car</RootNamespace>
     <AssemblyName>Org.SbeTool.Sbe.Example.Car</AssemblyName>
@@ -16,8 +16,4 @@
     <ProjectReference Include="..\sbe-generated\sbe-generated.csproj" />
   </ItemGroup>
 
-  <ItemGroup>
-    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-preview.2" PrivateAssets="All" />
-  </ItemGroup>
-
 </Project>
diff --git a/csharp/sbe-samples-extension/sbe-samples-extension.csproj b/csharp/sbe-samples-extension/sbe-samples-extension.csproj
index 97899b3aa4..f4f7a7e311 100644
--- a/csharp/sbe-samples-extension/sbe-samples-extension.csproj
+++ b/csharp/sbe-samples-extension/sbe-samples-extension.csproj
@@ -1,11 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net45;netstandard2.0</TargetFrameworks>
+    <TargetFramework>net8.0</TargetFramework>
     <OutputTypeEx>exe</OutputTypeEx>
     <RootNamespace>Org.SbeTool.Sbe.Example.Extension</RootNamespace>
     <AssemblyName>Org.SbeTool.Sbe.Example.Extension</AssemblyName>
-    <Copyright>Copyright (C) Bill Segall 2018, MarketFactory Inc 2017, Adaptive 2014. All rights reserved.</Copyright>
+    <Copyright>Copyright (C) Bill Segall 2018, MarketFactory Inc 2017, Adaptive 2014-2024. All rights reserved.</Copyright>
   </PropertyGroup>
 
   <ItemGroup>
@@ -17,9 +17,4 @@
     <ProjectReference Include="..\sbe-generated\sbe-generated.csproj" />
   </ItemGroup>
 
-  <ItemGroup>
-    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-preview.2" PrivateAssets="All" />
-
-  </ItemGroup>
-
 </Project>
diff --git a/csharp/sbe-tests/sbe-tests.csproj b/csharp/sbe-tests/sbe-tests.csproj
index 468a1ab8ba..4d8bcee13f 100644
--- a/csharp/sbe-tests/sbe-tests.csproj
+++ b/csharp/sbe-tests/sbe-tests.csproj
@@ -1,10 +1,10 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net45;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>net8.0</TargetFrameworks>
     <RootNamespace>Org.SbeTool.Sbe.Tests</RootNamespace>
     <AssemblyName>Org.SbeTool.Sbe.UnitTests</AssemblyName>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
-    <Copyright>Copyright (C) Bill Segall 2018, MarketFactory Inc 2017, Adaptive 2014. All rights reserved.</Copyright>
+    <Copyright>Copyright (C) Bill Segall 2018, MarketFactory Inc 2017, Adaptive 2014-2024. All rights reserved.</Copyright>
   </PropertyGroup>
 
   <ItemGroup>
@@ -18,10 +18,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-preview.2" PrivateAssets="All" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.2.0" />
-    <PackageReference Include="MSTest.TestAdapter" Version="1.4.0" />
-    <PackageReference Include="MSTest.TestFramework" Version="1.4.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="3.2.2" />
+    <PackageReference Include="MSTest.TestFramework" Version="3.2.2" />
   </ItemGroup>
 
 </Project>