diff --git a/build/build-variables.yml b/build/build-variables.yml
index cc418e9f12..5916939a96 100644
--- a/build/build-variables.yml
+++ b/build/build-variables.yml
@@ -3,7 +3,7 @@
 # Variables used during builds.
 
 variables:
-  NET_CORE_SDK: 7.0.x
+  NET_CORE_SDK: 8.0.x
   DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
-  TEST_TARGETFRAMEWORK: net6.0
+  TEST_TARGETFRAMEWORK: net8.0
   buildConfiguration: Release
\ No newline at end of file
diff --git a/build/templates/test-job-template.yml b/build/templates/test-job-template.yml
index ccee378956..2933867507 100644
--- a/build/templates/test-job-template.yml
+++ b/build/templates/test-job-template.yml
@@ -10,7 +10,7 @@ steps:
   displayName: 'Use .NET Core sdk $(NET_CORE_SDK)'
   inputs:
     packageType: runtime
-    version: 6.0.x
+    version: $(NET_CORE_SDK)
 - task: DownloadPipelineArtifact@2
   inputs:
     displayName: Download Build artifacts
diff --git a/src/Benchmarks/Benchmarks.csproj b/src/Benchmarks/Benchmarks.csproj
index 3d9a7c2a59..746eab0d33 100644
--- a/src/Benchmarks/Benchmarks.csproj
+++ b/src/Benchmarks/Benchmarks.csproj
@@ -2,7 +2,7 @@
 
 	<PropertyGroup>
 		<OutputType>Exe</OutputType>
-		<TargetFramework>net6.0</TargetFramework>
+		<TargetFramework>net8.0</TargetFramework>
 		<AssemblyName>Benchmarks</AssemblyName>
 		<RootNamespace>Firely.Sdk.Benchmarks</RootNamespace>
 	</PropertyGroup>
diff --git a/src/Hl7.Fhir.Specification.STU3.Tests/Source/ArtifactSourceTests.cs b/src/Hl7.Fhir.Specification.STU3.Tests/Source/ArtifactSourceTests.cs
index 5e6643e485..9be1dbc6a0 100644
--- a/src/Hl7.Fhir.Specification.STU3.Tests/Source/ArtifactSourceTests.cs
+++ b/src/Hl7.Fhir.Specification.STU3.Tests/Source/ArtifactSourceTests.cs
@@ -16,7 +16,7 @@
 using System.IO;
 using System.Linq;
 using System.Threading;
-using ssac = System.Security.AccessControl;
+using Ssac = System.Security.AccessControl;
 using T = System.Threading.Tasks;
 
 namespace Hl7.Fhir.Specification.Tests
@@ -346,7 +346,7 @@ public void TestAccessPermissions()
 
                 // Revoke folder read permissions for the current user
                 string userName = System.Security.Principal.WindowsIdentity.GetCurrent().Name;
-                var rule = new ssac.FileSystemAccessRule(userName, ssac.FileSystemRights.Read, ssac.AccessControlType.Deny);
+                var rule = new Ssac.FileSystemAccessRule(userName, Ssac.FileSystemRights.Read, Ssac.AccessControlType.Deny);
                 ds.AddAccessRule(rule);
                 Debug.Print($"Removing read permissions from folder: '{subPath2}' ...");
 
diff --git a/src/Hl7.Fhir.Specification.Shared.Tests/Source/ArtifactSourceTests.cs b/src/Hl7.Fhir.Specification.Shared.Tests/Source/ArtifactSourceTests.cs
index 1ae33ce9a3..9cd771fcb4 100644
--- a/src/Hl7.Fhir.Specification.Shared.Tests/Source/ArtifactSourceTests.cs
+++ b/src/Hl7.Fhir.Specification.Shared.Tests/Source/ArtifactSourceTests.cs
@@ -17,7 +17,7 @@
 using System.IO;
 using System.Linq;
 using System.Threading;
-using ssac = System.Security.AccessControl;
+using Ssac = System.Security.AccessControl;
 using T = System.Threading.Tasks;
 
 namespace Hl7.Fhir.Specification.Tests
@@ -344,7 +344,7 @@ public void TestAccessPermissions()
 
                 // Revoke folder read permissions for the current user
                 string userName = System.Security.Principal.WindowsIdentity.GetCurrent().Name;
-                var rule = new ssac.FileSystemAccessRule(userName, ssac.FileSystemRights.Read, ssac.AccessControlType.Deny);
+                var rule = new Ssac.FileSystemAccessRule(userName, Ssac.FileSystemRights.Read, Ssac.AccessControlType.Deny);
                 ds.AddAccessRule(rule);
                 Debug.Print($"Removing read permissions from folder: '{subPath2}' ...");
 
diff --git a/src/Hl7.FhirPath.R4.Tests/PocoTests/FhirPathEvaluatorTestFromSpec.cs b/src/Hl7.FhirPath.R4.Tests/PocoTests/FhirPathEvaluatorTestFromSpec.cs
index e6c7ef0921..bd3416d1f8 100644
--- a/src/Hl7.FhirPath.R4.Tests/PocoTests/FhirPathEvaluatorTestFromSpec.cs
+++ b/src/Hl7.FhirPath.R4.Tests/PocoTests/FhirPathEvaluatorTestFromSpec.cs
@@ -16,7 +16,7 @@
 using System.IO;
 using System.Linq;
 using System.Xml.Linq;
-using boolean = System.Boolean;
+using Boolean = System.Boolean;
 using DecimalType = Hl7.Fhir.Model.FhirDecimal; // System.Decimal;
 using Model = Hl7.Fhir.Model;
 using P = Hl7.Fhir.ElementModel.Types;
@@ -64,7 +64,7 @@ private static bool compare(XElement expected, ITypedElement actual)
         }
 
         // @SuppressWarnings("deprecation")
-        private void testBoolean(Model.Resource resource, Model.Base focus, String focusType, String expression, boolean value)
+        private void testBoolean(Model.Resource resource, Model.Base focus, String focusType, String expression, Boolean value)
         {
             var input = focus.ToTypedElement();
             var container = resource?.ToTypedElement();
diff --git a/src/firely-net-sdk-tests.props b/src/firely-net-sdk-tests.props
index 812d5816c8..822b19cdd5 100644
--- a/src/firely-net-sdk-tests.props
+++ b/src/firely-net-sdk-tests.props
@@ -1,18 +1,14 @@
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 	<PropertyGroup>
-		<TargetFrameworks>net6.0</TargetFrameworks>
-		<LangVersion>11.0</LangVersion>
+		<TargetFrameworks>net8.0</TargetFrameworks>
+		<LangVersion>12.0</LangVersion>
+		<EnableUnsafeBinaryFormatterSerialization>true</EnableUnsafeBinaryFormatterSerialization>
 	</PropertyGroup>
 
 	<PropertyGroup>
 		<ContainsTests>true</ContainsTests>
 	</PropertyGroup>
 
-	<!-- General compiler settings -->
-	<PropertyGroup>
-		<LangVersion>11.0</LangVersion>
-	</PropertyGroup>
-
 	<PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|netcoreapp2.1|AnyCPU'">
 		<DefineConstants>DEBUG;TRACE</DefineConstants>
 	</PropertyGroup>
diff --git a/src/firely-net-sdk.props b/src/firely-net-sdk.props
index 46300a6108..8152ae4cb9 100644
--- a/src/firely-net-sdk.props
+++ b/src/firely-net-sdk.props
@@ -1,7 +1,7 @@
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
 	<PropertyGroup>
-		<TargetFrameworks>net6.0;netstandard2.0</TargetFrameworks>
+		<TargetFrameworks>net8.0;netstandard2.0</TargetFrameworks>
 	</PropertyGroup>
 
 	<!-- Solution-wide properties for NuGet packaging -->
@@ -39,7 +39,7 @@
 
 	<!-- Compiler settings -->
 	<PropertyGroup>
-		<LangVersion>11.0</LangVersion>
+		<LangVersion>12.0</LangVersion>
 		<GenerateDocumentationFile>True</GenerateDocumentationFile>
 		<Configurations>Debug;Release;FullDebug</Configurations>
 		<TreatWarningsAsErrors>true</TreatWarningsAsErrors>