Particular · bording · Jun 26, 2025 · May 21, 2025 · Jun 25, 2025 · Jun 25, 2025
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -30,8 +30,8 @@ jobs:
       - name: Setup .NET SDK
         uses: actions/setup-dotnet@v4.3.1
         with:
-          dotnet-version: 8.0.x
+          global-json-file: global.json
       - name: Build
         run: dotnet build src --configuration Release
       - name: Run tests
-        uses: Particular/run-tests-action@v1.7.0
+        uses: Particular/run-tests-action@v1.7.0
diff --git a/global.json b/global.json
@@ -1,6 +1,7 @@
 {
   "sdk": {
-    "version": "8.0.400",
+    "version": "10.0.0",
+    "allowPrerelease": true,
     "rollForward": "latestFeature"
   }
 }
diff --git a/src/Common/Common.csproj b/src/Common/Common.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>

diff --git a/src/Common/Program.cs b/src/Common/Program.cs
@@ -26,11 +26,14 @@ static void Main(string[] args)
         var serializers = new[]
         {
             Type.GetType("JsonSerializerFacade", true),
+#if SYSTEMJSON
+            Type.GetType("SystemJsonSerializerFacade", true),
+#endif
             Type.GetType("XmlSerializerFacade", true)
         };
         var testCases = DiscoverTestCases();
 
-        if (args.Contains("Serialize") || args.Length == 0)
+        if (args.Contains("serialize", StringComparer.OrdinalIgnoreCase) || args.Length == 0)
         {
             Console.WriteLine("Running Serialization tests for:");
             Assert.Multiple(() =>
@@ -50,7 +53,7 @@ static void Main(string[] args)
             });
         }
 
-        if (args.Contains("Deserialize") || args.Length == 0)
+        if (args.Contains("deserialize", StringComparer.OrdinalIgnoreCase) || args.Length == 0)
         {
             Console.WriteLine("Running Deserialization tests for:");
             Assert.Multiple(() =>
@@ -83,8 +86,7 @@ static void DeserializeAndVerify(ISerializerFacade serializer, TestCase testCase
         var files = Directory.GetFiles(testCaseFolder);
         if (files.Length == 0)
         {
-            throw new Exception(
-                "No available files to deserialize. Make sure to run the serialization test case first.");
+            throw new Exception("No available files to deserialize. Make sure to run the serialization test case first.");
         }
 
         foreach (var filePath in files)

diff --git a/src/Common/Tests/TestCases/TestPolymorphicCollections.cs b/src/Common/Tests/TestCases/TestPolymorphicCollections.cs
@@ -31,10 +31,10 @@ public override object CreateInstance() =>
 
         public override void CheckIfAreEqual(object expectedObj, object actualObj)
         {
-            var expected = (Polymorphic)actualObj;
-            var actual = (Polymorphic)expectedObj;
+            var expected = (Polymorphic)expectedObj;
+            var actual = (Polymorphic)actualObj;
 
-            Assert.That(actual.Items, Is.EqualTo(expected.Items).AsCollection, "Polymorphic object graph does not match.");
+            Assert.That(actual.Items, Is.EqualTo(expected.Items), "Polymorphic object graph does not match.");
         }
     }
 }
diff --git a/src/Custom.Build.props b/src/Custom.Build.props
@@ -1,7 +1,7 @@
 <Project>
 
   <PropertyGroup>
-    <LangVersion>12.0</LangVersion>
+    <LangVersion>preview</LangVersion>
   </PropertyGroup>
 
 </Project>
diff --git a/src/NServiceBus.Serializers.CompatTests.sln b/src/NServiceBus.Serializers.CompatTests.sln
diff --git a/src/NServiceBus.Serializers.CompatTests.slnx b/src/NServiceBus.Serializers.CompatTests.slnx
@@ -0,0 +1,41 @@
+<Solution>
+  <Folder Name="/Solution Items/">
+    <File Path="Custom.Build.props" />
+  </Folder>
+  <Project Path="Common/Common.csproj" />
+  <Project Path="NServiceBus10.0/NServiceBus10.0.csproj" />
+  <Project Path="NServiceBus3.3/NServiceBus3.3.csproj" />
+  <Project Path="NServiceBus4.0/NServiceBus4.0.csproj" />
+  <Project Path="NServiceBus4.1/NServiceBus4.1.csproj" />
+  <Project Path="NServiceBus4.2/NServiceBus4.2.csproj" />
+  <Project Path="NServiceBus4.3/NServiceBus4.3.csproj" />
+  <Project Path="NServiceBus4.4/NServiceBus4.4.csproj" />
+  <Project Path="NServiceBus4.5/NServiceBus4.5.csproj" />
+  <Project Path="NServiceBus4.6/NServiceBus4.6.csproj" />
+  <Project Path="NServiceBus4.7/NServiceBus4.7.csproj" />
+  <Project Path="NServiceBus5.0/NServiceBus5.0.csproj" />
+  <Project Path="NServiceBus5.1/NServiceBus5.1.csproj" />
+  <Project Path="NServiceBus5.2/NServiceBus5.2.csproj" />
+  <Project Path="NServiceBus6.0/NServiceBus6.0.csproj" />
+  <Project Path="NServiceBus6.1/NServiceBus6.1.csproj" />
+  <Project Path="NServiceBus6.2/NServiceBus6.2.csproj" />
+  <Project Path="NServiceBus6.3/NServiceBus6.3.csproj" />
+  <Project Path="NServiceBus6.4/NServiceBus6.4.csproj" />
+  <Project Path="NServiceBus6.5/NServiceBus6.5.csproj" />
+  <Project Path="NServiceBus7.0/NServiceBus7.0.csproj" />
+  <Project Path="NServiceBus7.1/NServiceBus7.1.csproj" />
+  <Project Path="NServiceBus7.2/NServiceBus7.2.csproj" />
+  <Project Path="NServiceBus7.3/NServiceBus7.3.csproj" />
+  <Project Path="NServiceBus7.4/NServiceBus7.4.csproj" />
+  <Project Path="NServiceBus7.5/NServiceBus7.5.csproj" />
+  <Project Path="NServiceBus7.6/NServiceBus7.6.csproj" />
+  <Project Path="NServiceBus7.7/NServiceBus7.7.csproj" />
+  <Project Path="NServiceBus7.8/NServiceBus7.8.csproj" />
+  <Project Path="NServiceBus8.0/NServiceBus8.0.csproj" />
+  <Project Path="NServiceBus8.1/NServiceBus8.1.csproj" />
+  <Project Path="NServiceBus8.2/NServiceBus8.2.csproj" />
+  <Project Path="NServiceBus9.0/NServiceBus9.0.csproj" />
+  <Project Path="NServiceBus9.1/NServiceBus9.1.csproj" />
+  <Project Path="NServiceBus9.2/NServiceBus9.2.csproj" />
+  <Project Path="Tests/Tests.csproj" />
+</Solution>
diff --git a/src/NServiceBus9.1/ExcludeList.cs → src/NServiceBus10.0/ExcludeList.cs b/src/NServiceBus9.1/ExcludeList.cs → src/NServiceBus10.0/ExcludeList.cs
diff --git a/src/NServiceBus9.1/JsonSerializerFacade.cs → src/NServiceBus10.0/JsonSerializerFacade.cs b/src/NServiceBus9.1/JsonSerializerFacade.cs → src/NServiceBus10.0/JsonSerializerFacade.cs
diff --git a/src/NServiceBus10.0/NServiceBus10.0.csproj b/src/NServiceBus10.0/NServiceBus10.0.csproj
@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>NServiceBus10._0</RootNamespace>
+    <DefineConstants>SYSTEMJSON</DefineConstants>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Common\Common.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="NServiceBus" Version="10.*-*" />
+    <PackageReference Include="NServiceBus.Newtonsoft.Json" Version="5.*-*" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Compile Include="..\Common\Program.cs" />
+  </ItemGroup>
+
+</Project>
diff --git a/src/NServiceBus9.1/StreamExtensions.cs → src/NServiceBus10.0/StreamExtensions.cs b/src/NServiceBus9.1/StreamExtensions.cs → src/NServiceBus10.0/StreamExtensions.cs
diff --git a/src/NServiceBus9.2/JsonSerializerFacade.cs → ...viceBus10.0/SystemJsonSerializerFacade.cs b/src/NServiceBus9.2/JsonSerializerFacade.cs → ...viceBus10.0/SystemJsonSerializerFacade.cs
@@ -1,29 +1,26 @@
-using System;
+using System;
 using System.IO;
 using Common;
 using Common.Tests;
-using Newtonsoft.Json;
 using NServiceBus;
 using NServiceBus.MessageInterfaces.MessageMapper.Reflection;
 using NServiceBus.Serialization;
 using NServiceBus.Settings;
 
-class JsonSerializerFacade : ISerializerFacade
+class SystemJsonSerializerFacade : ISerializerFacade
 {
-    public JsonSerializerFacade(params Type[] objectTypes)
+    public SystemJsonSerializerFacade(params Type[] objectTypes)
     {
         this.objectTypes = objectTypes;
         mapper = new MessageMapper();
         mapper.Initialize(objectTypes);
         var settings = new SettingsHolder();
 
-        var jsonSettings = new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.Auto };
-        settings.Set("NServiceBus.Newtonsoft.Json.Settings", jsonSettings);
-        var ser = new NewtonsoftJsonSerializer();
+        var ser = new SystemJsonSerializer();
         serializer = ser.Configure(settings)(mapper);
     }
 
-    public SerializationFormat SerializationFormat => SerializationFormat.Json;
+    public SerializationFormat SerializationFormat => SerializationFormat.SystemJson;
 
     public void Serialize(Stream stream, object instance)
     {

diff --git a/src/NServiceBus9.1/XmlSerializerFacade.cs → src/NServiceBus10.0/XmlSerializerFacade.cs b/src/NServiceBus9.1/XmlSerializerFacade.cs → src/NServiceBus10.0/XmlSerializerFacade.cs
diff --git a/src/NServiceBus7.0/NServiceBus7.0.csproj b/src/NServiceBus7.0/NServiceBus7.0.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus7._0</RootNamespace>
   </PropertyGroup>
@@ -16,9 +16,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Drawing.Common" Version="4.*" />
-    <PackageReference Include="System.Private.Uri" Version="4.*" />
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="4.*" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="10.*-*" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/src/NServiceBus7.1/NServiceBus7.1.csproj b/src/NServiceBus7.1/NServiceBus7.1.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus7._1</RootNamespace>
   </PropertyGroup>
@@ -16,10 +16,9 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Drawing.Common" Version="4.*" />
-    <PackageReference Include="System.Private.Uri" Version="4.*" />
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="4.*" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="10.*-*" />
   </ItemGroup>
+
   <ItemGroup>
     <Compile Include="..\Common\Program.cs" />
     <Compile Include="..\NServiceBus7.0\*.cs" />

diff --git a/src/NServiceBus7.2/NServiceBus7.2.csproj b/src/NServiceBus7.2/NServiceBus7.2.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus7._2</RootNamespace>
   </PropertyGroup>
@@ -16,9 +16,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Drawing.Common" Version="4.*" />
-    <PackageReference Include="System.Private.Uri" Version="4.*" />
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="4.*" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="10.*-*" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/src/NServiceBus7.3/NServiceBus7.3.csproj b/src/NServiceBus7.3/NServiceBus7.3.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus7._3</RootNamespace>
   </PropertyGroup>
@@ -16,8 +16,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Drawing.Common" Version="4.*" />
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="4.*" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="10.*-*" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/src/NServiceBus7.4/NServiceBus7.4.csproj b/src/NServiceBus7.4/NServiceBus7.4.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus7._4</RootNamespace>
   </PropertyGroup>
@@ -16,8 +16,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Drawing.Common" Version="4.*" />
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="4.*" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="10.*-*" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/src/NServiceBus7.5/NServiceBus7.5.csproj b/src/NServiceBus7.5/NServiceBus7.5.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus7._5</RootNamespace>
   </PropertyGroup>
@@ -16,8 +16,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Drawing.Common" Version="4.*" />
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="4.*" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="10.*-*" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/src/NServiceBus7.6/NServiceBus7.6.csproj b/src/NServiceBus7.6/NServiceBus7.6.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus7._6</RootNamespace>
   </PropertyGroup>
@@ -16,8 +16,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Drawing.Common" Version="4.*" />
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="4.*" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="10.*-*" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/src/NServiceBus7.7/NServiceBus7.7.csproj b/src/NServiceBus7.7/NServiceBus7.7.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus7._7</RootNamespace>
   </PropertyGroup>
@@ -16,7 +16,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Drawing.Common" Version="4.*" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="10.*-*" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/src/NServiceBus7.8/NServiceBus7.8.csproj b/src/NServiceBus7.8/NServiceBus7.8.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus7._8</RootNamespace>
   </PropertyGroup>
@@ -16,7 +16,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Drawing.Common" Version="4.*" />
+    <PackageReference Include="System.Security.Cryptography.Xml" Version="10.*-*" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/src/NServiceBus8.0/NServiceBus8.0.csproj b/src/NServiceBus8.0/NServiceBus8.0.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0</TargetFrameworks>
+    <TargetFrameworks>net472;net10.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>NServiceBus8._0</RootNamespace>
   </PropertyGroup>
@@ -16,8 +16,7 @@
   </ItemGroup>
 
   <ItemGroup Label="Direct references to transitive dependencies to avoid versions with CVE">
-    <PackageReference Include="System.Security.Cryptography.Xml" Version="8.*" />
-    <PackageReference Include="System.Text.Json" Version="8.*" />
+    <PackageReference Include="System.Text.Json" Version="10.*-*" Condition="'$(TargetFramework)' == 'net472'" />
   </ItemGroup>
 
   <ItemGroup>