diff --git a/GitVersion.yml b/GitVersion.yml
index e4a74f1aa..acdf7df63 100644
--- a/GitVersion.yml
+++ b/GitVersion.yml
@@ -1,4 +1,4 @@
-next-version: 3.19.0
+next-version: 3.20.0
 mode: ContinuousDelivery
 legacy-semver-padding: 5
 build-metadata-padding: 5
diff --git a/build.cake b/build.cake
index b27eca365..70695513f 100644
--- a/build.cake
+++ b/build.cake
@@ -65,7 +65,7 @@ BuildSettings.Packages.AddRange(new PackageDefinition[] {
             HasDirectory("tools/agents/net462").WithFiles(AGENT_FILES),
             HasDirectory("tools/agents/net6.0").WithFiles(AGENT_FILES_NETCORE),
             HasDirectory("tools/agents/net8.0").WithFiles(AGENT_FILES_NETCORE),
-            HasDirectory("tools/agents/net9.0").WithFiles(AGENT_FILES_NETCORE)
+            HasDirectory("tools/agents/net9.0").WithFiles(AGENT_FILES_NETCORE).WithFile("System.Runtime.Serialization.Formatters.dll")
         },
         symbols: new PackageCheck[] {
             HasDirectory("tools").WithFiles(ENGINE_PDB_FILES).AndFile("nunit3-console.pdb"),
@@ -125,7 +125,8 @@ BuildSettings.Packages.AddRange(new PackageDefinition[] {
             HasDirectory("bin/agents/net462").WithFiles(AGENT_FILES).AndFiles(AGENT_PDB_FILES),
             HasDirectory("bin/agents/net6.0").WithFiles(AGENT_FILES_NETCORE).AndFiles(AGENT_PDB_FILES_NETCORE),
             HasDirectory("bin/agents/net8.0").WithFiles(AGENT_FILES_NETCORE).AndFiles(AGENT_PDB_FILES_NETCORE),
-            HasDirectory("bin/agents/net9.0").WithFiles(AGENT_FILES_NETCORE).AndFiles(AGENT_PDB_FILES_NETCORE),
+            HasDirectory("bin/agents/net9.0").WithFiles(AGENT_FILES_NETCORE).AndFiles(AGENT_PDB_FILES_NETCORE)
+                .AndFile("System.Runtime.Serialization.Formatters.dll")
         },
         testRunner: new ConsoleRunnerSelfTester(BuildSettings.ZipTestDirectory
             + $"NUnit.Console.{BuildSettings.PackageVersion}/bin/net462/nunit3-console.exe"),
diff --git a/choco/nunit-console-runner.nuspec b/choco/nunit-console-runner.nuspec
index 0f2f8a30d..dab777ccb 100644
--- a/choco/nunit-console-runner.nuspec
+++ b/choco/nunit-console-runner.nuspec
@@ -85,6 +85,7 @@
     <file src = "$BIN_DIR$agents/net9.0/nunit.engine.core.dll" target="tools/agents/net9.0" />
     <file src = "$BIN_DIR$agents/net9.0/testcentric.engine.metadata.dll" target="tools/agents/net9.0" />
     <file src = "$BIN_DIR$agents/net9.0/Microsoft.Extensions.DependencyModel.dll" target="tools/agents/net9.0" />
+    <file src = "$BIN_DIR$agents/net9.0/System.Runtime.Serialization.Formatters.dll" target="tools/agents/net9.0" />
     <!-- File used by ExtensionManager to indicate this is a chocolatey installation -->
     <file src = "VERIFICATION.txt" target = "tools/agents/net9.0" />
   </files>
diff --git a/nuget/runners/nunit.console-runner.nuspec b/nuget/runners/nunit.console-runner.nuspec
index 7e637f6af..85772b506 100644
--- a/nuget/runners/nunit.console-runner.nuspec
+++ b/nuget/runners/nunit.console-runner.nuspec
@@ -78,6 +78,7 @@
     <file src="agents/net9.0/nunit.engine.core.pdb" target="tools/agents/net9.0" />
     <file src="agents/net9.0/testcentric.engine.metadata.dll" target="tools/agents/net9.0" />
     <file src="agents/net9.0/Microsoft.Extensions.DependencyModel.dll" target="tools/agents/net9.0" />
+    <file src="agents/net9.0/System.Runtime.Serialization.Formatters.dll" target="tools/agents/net9.0" />
 
     <file src="net462/nunit3-console.exe" target="tools" />
     <file src="net462/nunit3-console.pdb" target="tools" />
diff --git a/package-tests.cake b/package-tests.cake
index 7a1c97643..be6c014fb 100644
--- a/package-tests.cake
+++ b/package-tests.cake
@@ -46,6 +46,13 @@ public static class PackageTests
             ExpectedResult=new MockAssemblyExpectedResult("net-4.6.2")
         });
 
+        AllLists.Add(new PackageTest(1, "Net90Test")
+        {
+            Description = "Run mock-assembly.dll targeting .NET 9.0",
+            Arguments = "testdata/net9.0/mock-assembly.dll",
+            ExpectedResult = new MockAssemblyExpectedResult("netcore-9.0")
+        });
+
         AllLists.Add(new PackageTest(1, "Net80Test")
         {
             Description = "Run mock-assembly.dll targeting .NET 8.0",
@@ -230,14 +237,14 @@ public static class PackageTests
         AllLists.Add(new PackageTest(1, "Net60WPFTest")
         {
             Description = "Run test using WPF targeting .NET 6.0",
-            Arguments = "testdata/net6.0-windows/WpfTest.dll --trace=Debug",
+            Arguments = "testdata/net6.0-windows/WpfTest.dll",
             ExpectedResult = new ExpectedResult("Passed") { Assemblies = new[] { new ExpectedAssemblyResult("WpfTest.dll", "netcore-6.0") } }
         });
 
         AllLists.Add(new PackageTest(1, "Net80WPFTest")
         {
             Description = "Run test using WPF targeting .NET 8.0",
-            Arguments = "testdata/net8.0-windows/WpfTest.dll --trace=Debug",
+            Arguments = "testdata/net8.0-windows/WpfTest.dll",
             ExpectedResult = new ExpectedResult("Passed") { Assemblies = new[] { new ExpectedAssemblyResult("WpfTest.dll", "netcore-8.0") } }
         });
 
@@ -301,22 +308,22 @@ public static class PackageTests
         {
             Description = "Run mock-assembly using the .csproj file",
             Arguments = "../../src/TestData/mock-assembly/mock-assembly.csproj --config=Release",
-            ExpectedResult = new MockAssemblyExpectedResult("net462", "netcore-3.1", "netcore-6.0", "netcore-7.0", "netcore-8.0"),
+            ExpectedResult = new MockAssemblyExpectedResult("net462", "netcore-3.1", "netcore-6.0", "netcore-7.0", "netcore-8.0", "netcore-9.0"),
             ExtensionsNeeded = new[] { Extensions.VSProjectLoader }
         });
 
         StandardAndZipLists.Add(new PackageTest(1, "VSProjectLoaderTest_Solution")
         {
             Description = "Run mock-assembly using the .sln file",
-            Arguments = "../../src/TestData/TestData.sln --config=Release --trace=Debug",
+            Arguments = "../../src/TestData/TestData.sln --config=Release",
             ExpectedResult = new ExpectedResult("Failed")
             {
-                Total = 37 * 5,
-                Passed = 23 * 5,
-                Failed = 5 * 5,
-                Warnings = 1 * 5,
-                Inconclusive = 1 * 5,
-                Skipped = 7 * 5,
+                Total = 37 * 6,
+                Passed = 23 * 6,
+                Failed = 5 * 6,
+                Warnings = 1 * 6,
+                Inconclusive = 1 * 6,
+                Skipped = 7 * 6,
                 Assemblies = new ExpectedAssemblyResult[]
                 {
                     new ExpectedAssemblyResult("mock-assembly.dll", "net-4.6.2"),
@@ -324,6 +331,7 @@ public static class PackageTests
                     new ExpectedAssemblyResult("mock-assembly.dll", "netcore-6.0"),
                     new ExpectedAssemblyResult("mock-assembly.dll", "netcore-7.0"),
                     new ExpectedAssemblyResult("mock-assembly.dll", "netcore-8.0"),
+                    new ExpectedAssemblyResult("mock-assembly.dll", "netcore-9.0"),
                     new ExpectedAssemblyResult("notest-assembly.dll", "net-4.6.2"),
                     new ExpectedAssemblyResult("notest-assembly.dll", "netcore-3.1"),
                     new ExpectedAssemblyResult("notest-assembly.dll", "netstandard-2.0"),
@@ -337,7 +345,7 @@ public static class PackageTests
         StandardAndZipLists.Add(new PackageTest(1, "Net462TeamCityListenerTest1")
         {
             Description = "Run mock-assembly targeting .NET 4.6.2 with --teamcity option",
-            Arguments = "testdata/net462/mock-assembly.dll --teamcity --trace:Debug",
+            Arguments = "testdata/net462/mock-assembly.dll --teamcity",
             ExpectedResult = new MockAssemblyExpectedResult("net-4.6.2"),
             ExtensionsNeeded = new[] { Extensions.TeamCityEventListener },
             OutputCheck = new OutputContains("##teamcity")
@@ -347,7 +355,7 @@ public static class PackageTests
         StandardAndZipLists.Add(new PackageTest(1, "Net462TeamCityListenerTest2")
         {
             Description = "Run mock-assembly targeting .NET 4.6.2 with --enable teamcity option",
-            Arguments = "testdata/net462/mock-assembly.dll --enable:NUnit.Engine.Listeners.TeamCityEventListener --trace:Debug",
+            Arguments = "testdata/net462/mock-assembly.dll --enable:NUnit.Engine.Listeners.TeamCityEventListener",
             ExpectedResult = new MockAssemblyExpectedResult("net-4.6.2"),
             ExtensionsNeeded = new[] { Extensions.TeamCityEventListener },
             OutputCheck = new OutputContains("##teamcity")
@@ -356,7 +364,7 @@ public static class PackageTests
         AllLists.Add(new PackageTest(1, "Net60TeamCityListenerTest1")
         {
             Description = "Run mock-assembly targeting .NET 6.0 with --teamcity option",
-            Arguments = "testdata/net6.0/mock-assembly.dll --teamcity --trace:Debug",
+            Arguments = "testdata/net6.0/mock-assembly.dll --teamcity",
             ExpectedResult = new MockAssemblyExpectedResult("net-6.0"),
             ExtensionsNeeded = new[] { Extensions.TeamCityEventListener },
             OutputCheck = new OutputContains("##teamcity")
@@ -366,7 +374,7 @@ public static class PackageTests
         AllLists.Add(new PackageTest(1, "Net60TeamCityListenerTest2")
         {
             Description = "Run mock-assembly targeting .NET 6.0 with --enable teamcity option",
-            Arguments = "testdata/net6.0/mock-assembly.dll --enable:NUnit.Engine.Listeners.TeamCityEventListener --trace:Debug",
+            Arguments = "testdata/net6.0/mock-assembly.dll --enable:NUnit.Engine.Listeners.TeamCityEventListener",
             ExpectedResult = new MockAssemblyExpectedResult("net-6.0"),
             ExtensionsNeeded = new[] { Extensions.TeamCityEventListener },
             OutputCheck = new OutputContains("##teamcity")
@@ -414,7 +422,7 @@ public static class PackageTests
         StandardAndZipLists.Add(new PackageTest(1, "InvalidTestNameTest_Net462")
         {
             Description = "Ensure we handle invalid test names correctly targeting .NET 4.6.2",
-            Arguments = "testdata/net462/InvalidTestNames.dll --trace:Debug",
+            Arguments = "testdata/net462/InvalidTestNames.dll",
             ExpectedResult = new ExpectedResult("Passed")
             {
                 Assemblies = new ExpectedAssemblyResult[] { new ExpectedAssemblyResult("InvalidTestNames.dll", "net-4.6.2") }
@@ -424,7 +432,7 @@ public static class PackageTests
         AllLists.Add(new PackageTest(1, "InvalidTestNameTest_Net60")
         {
             Description = "Ensure we handle invalid test names correctly targeting .NET 6.0",
-            Arguments = "testdata/net6.0/InvalidTestNames.dll --trace:Debug",
+            Arguments = "testdata/net6.0/InvalidTestNames.dll",
             ExpectedResult = new ExpectedResult("Passed")
             {
                 Assemblies = new ExpectedAssemblyResult[] { new ExpectedAssemblyResult("InvalidTestNames.dll", "netcore-6.0") }
@@ -434,7 +442,7 @@ public static class PackageTests
         AllLists.Add(new PackageTest(1, "InvalidTestNameTest_Net80")
         {
             Description = "Ensure we handle invalid test names correctly targeting .NET 8.0",
-            Arguments = "testdata/net8.0/InvalidTestNames.dll --trace:Debug",
+            Arguments = "testdata/net8.0/InvalidTestNames.dll",
             ExpectedResult = new ExpectedResult("Passed")
             {
                 Assemblies = new ExpectedAssemblyResult[] { new ExpectedAssemblyResult("InvalidTestNames.dll", "netcore-8.0") }
diff --git a/src/NUnitEngine/nunit.engine.core.tests/nunit.engine.core.tests.csproj b/src/NUnitEngine/nunit.engine.core.tests/nunit.engine.core.tests.csproj
index 5a6350858..a78b9c67c 100644
--- a/src/NUnitEngine/nunit.engine.core.tests/nunit.engine.core.tests.csproj
+++ b/src/NUnitEngine/nunit.engine.core.tests/nunit.engine.core.tests.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <RootNamespace>NUnit.Engine.Core.Tests</RootNamespace>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net8.0;net9.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\..\nunit.snk</AssemblyOriginatorKeyFile>
diff --git a/src/NUnitEngine/nunit.engine.core/nunit.engine.core.csproj b/src/NUnitEngine/nunit.engine.core/nunit.engine.core.csproj
index ac5cc099a..7df5a6aa2 100644
--- a/src/NUnitEngine/nunit.engine.core/nunit.engine.core.csproj
+++ b/src/NUnitEngine/nunit.engine.core/nunit.engine.core.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <RootNamespace>NUnit.Engine</RootNamespace>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net8.0;net9.0</TargetFrameworks>
     <NoWarn>$(NoWarn);SYSLIB0011;SYSLIB0012</NoWarn><!-- TODO: Get rid of obsolete stuff -->
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\..\nunit.snk</AssemblyOriginatorKeyFile>
@@ -27,11 +27,15 @@
     <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="3.1.0" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)'=='net8.0'">
+  <ItemGroup Condition="'$(TargetFramework)'=='net8.0' or '$(TargetFramework)'=='net9.0'">
     <PackageReference Include="Microsoft.Win32.Registry" Version="4.3.0" />
     <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="8.0.2" />
   </ItemGroup>
 
+  <ItemGroup Condition="'$(TargetFramework)'=='net9.0'">
+    <PackageReference Include="System.Runtime.Serialization.Formatters" Version="9.0.3" />
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="TestCentric.Metadata" Version="2.0.0" />
   </ItemGroup>
diff --git a/src/TestData/mock-assembly-x86/mock-assembly-x86.csproj b/src/TestData/mock-assembly-x86/mock-assembly-x86.csproj
index 58003c7be..876fe1c72 100644
--- a/src/TestData/mock-assembly-x86/mock-assembly-x86.csproj
+++ b/src/TestData/mock-assembly-x86/mock-assembly-x86.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <RootNamespace>NUnit.Tests</RootNamespace>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net7.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net7.0;net8.0;net9.0</TargetFrameworks>
     <OutputPath>..\..\..\bin\$(Configuration)\testdata\</OutputPath>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\..\nunit.snk</AssemblyOriginatorKeyFile>
diff --git a/src/TestData/mock-assembly/mock-assembly.csproj b/src/TestData/mock-assembly/mock-assembly.csproj
index 4c7613a41..459ee644e 100644
--- a/src/TestData/mock-assembly/mock-assembly.csproj
+++ b/src/TestData/mock-assembly/mock-assembly.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <RootNamespace>NUnit.Tests</RootNamespace>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net7.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net7.0;net8.0;net9.0</TargetFrameworks>
     <OutputPath>..\..\..\bin\$(Configuration)\testdata\</OutputPath>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\..\nunit.snk</AssemblyOriginatorKeyFile>