Mapping UWP features to the Windows App SDK

This topic compares major feature areas in the different forms in which they appear in UWP and in the Windows App SDK. The content in this migration guide supports moving from UWP XAML to Windows App SDK XAML—moving to a different UI framework, such as Windows Presentation Foundation (WPF), is outside of the scope of this guidance.

Feature UWP Windows App SDK (packaged apps) Migration notes
Packaging MSIX
App has identity
App has identity
UWP apps migrating to the Windows App SDK should stay on MSIX to ensure trusted clean install and uninstall experience, as well as access to all APIs, including those that require identity.
Container App container:
- security = LowIL
- file system access is brokered
- no registry access
MSIX Container:
- security = MediumIL
- file system access same as user, AppData writes virtualized
- HKCU registry writes virtualized
Moving to a higher integrity level with the Windows App SDK allows your app to have greater functionality. However, be aware of virtualization if you want to expand the capabilities of your migrated application to write to HKCU or AppData.
Activation and instancing Package identity + CoreApplication activation, single-instanced by default Package identity, Main/WinMain + Windows App SDK activation, multi-instanced by default Ensure your application can handle multi-instance behavior, or use AppInstance to manage your instances.
Lifecycle-managed Suspend/resume Power/State notifications You can use Power/State change notifications to reduce system load.
Background tasks InProc and OOP background tasks Inproc COM and OOP background tasks You can continue to use your OOP background tasks. If the app requires communication to your main process, then evaluate your IPC mechanism, as the OOP background task is running in LowIL, and your Windows App SDK main process is running in MediumIL.

Any inproc background tasks need to be migrated to COM background tasks—see Create and register a winmain COM background task.

For C# OOP background tasks, see Author Windows Runtime components with C#/WinRT and the Background task sample.
Windowing CoreWindow, AppWindow (preview) HWND, AppWindow v2 Windowing behavior has significantly changed in Windows App SDK. See Windowing functionality migration.
Messaging CoreDispatcher and DispatcherQueue DispatcherQueue, WndProc DispatcherQueue supports Win32 apps. For additional details on moving from CoreDispatcher to DispatcherQueue see Threading functionality migration.
UI Platform System XAML, WebView, DirectX, and others WinUI 3, Webview2, DirectX, and others For more info, see Windows UI Library (WinUI) migration.
Text-rendering DirectWrite DWriteCore Enables applications to access the latest DWrite features downlevel and receive new DWrite updates separate from the OS release schedule. For more info, see DirectWrite to DWriteCore migration.
Resources MRT MRTCore For more info, see MRT to MRTCore migration.
.NET Runtime .NET Native / C# 7 .NET 6+/C# 9 The Windows App SDK provides access to the modern .NET runtime, and access to new langage features. However, .NET ReadyToRun compilation is not the same as .NET Native, so you should evaluate performance tradeoffs.
2D Graphics Win2D Win2D for WinUI 3 We're currently working on a version of Win2D that works with the Windows App SDK, in progress. See the documentation for more information.
Windows Runtime components Windows Runtime component project templates for UWP - C++: Use the Windows Runtime Component (WinUI 3) project template.
- C#: Use C#/WinRT to author Windows Runtime Components in a .NET Class Library.
We're currently working on support to Author Windows Runtime Components using C#/WinRT for use in the Windows App SDK and WinUI 3.