Document MTP v1 to v2 migration

Author: Youssef1313

docs/core/testing/microsoft-testing-platform-migration-from-v1-to-v2.md

@@ -0,0 +1,57 @@
+---
+title: Microsoft.Testing.Platform migration from v1 to v2
+description: Learn about migrating to Microsoft.Testing.Platform v2.
+author: Youssef1313
+ms.author: ygerges
+ms.date: 09/23/2025
+---
+
+# Migrate from Microsoft.Testing.Platform v1 to Microsoft.Testing.Platform v2
+
+The preview version Microsoft.Testing.Platform v2 is now available. This migration guide explores what's changed in Microsoft.Testing.Platform v2 and how you can migrate to this version.
+
+## Source breaking changes
+
+These are breaking changes that might cause build errors after migration.
+
+### Dropped unsupported target frameworks
+
+Support for target frameworks .NET Core 3.1 to .NET 7 is dropped. The minimum supported .NET version is .NET 8.
+This change doesn't affect .NET Framework. .NET Framework 4.6.2 continues to be the minimum supported .NET Framework target.
+
+### Remove obsolete types
+
+The following types were marked obsolete in MTP v1. In MTP v2, they are now removed:
+
+- `ITestApplicationLifecycleCallbacks`: use `ITestHostApplicationLifetime` instead.
+- `TestNodeFileArtifact`: use `FileArtifactProperty` instead.
+- `KeyValuePairStringProperty`: use `TestMetadataProperty` instead.
+- `TestSessionContext.Client`: use `IClientInfo` instead.
+
+This breaking change doesn't affect typical users of test frameworks. It only affects test framework authors and extension authors.
+
+### API signature changes
+
+- A `CancellationToken` parameter was added to `IOutputDevice.DisplayAsync`.
+- Methods in `ITestSessionLifetimeHandler` interface are changed to have a `ITestSessionContext` parameter instead of both `SessionUid` and `CancellationToken` parameters.
+- `IDataConsumer` is moved from `Microsoft.Testing.Platform.Extensions.TestHost` namespace to `Microsoft.Testing.Platform.Extensions`.
+
+This breaking change doesn't affect typical users of test frameworks. It only affects test framework authors and extension authors.
+
+## Behavior breaking changes
+
+These are breaking changes that might affect the behavior at run time.
+
+### Compatibility with VSTest-based `dotnet test`
+
+The `dotnet test` command has two implementations:
+
+1. VSTest-based implementation: this was the only implementation up to .NET 9 SDK.
+2. MTP-based implementation: this was added starting in .NET 10 SDK.
+
+Running MTP test projects with .NET 10 SDK now requires opting-in to the MTP-based `dotnet test` and can no longer be run with the VSTest-based implementation, which was previously enabled by `TestingPlatformDotnetTestSupport` MSBuild property in MTP v1.
+
+### Rename of command-line options
+
+- The `--diagnostic-output-fileprefix` command-line option was renamed to `--diagnostic-file-prefix`.
+- The `--diagnostic-filelogger-synchronouswrite` command-line option was renamed to `--diagnostic-synchronous-write`.

docs/navigate/devops-testing/toc.yml

@@ -77,6 +77,8 @@ items:
                 href: ../../core/testing/unit-testing-mstest-migration-v3-v4.md
               - name: Microsoft.Testing.Platform support (MSTest runner)
                 href: ../../core/testing/unit-testing-mstest-runner-intro.md
+              - name: Migrate from Microsoft.Testing.Platform v1 to Microsoft.Testing.Platform v2
+                href: ../../core/testing/microsoft-testing-platform-migration-from-v1-to-v2.md
               - name: Getting started
                 items:
                   - name: Overview