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Experimental channel release notes for the Windows App SDK

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Important

The experimental channel is not supported for use in production environments, and apps that use the experimental releases cannot be published to the Microsoft Store.

The experimental channel provides releases of the Windows App SDK that include experimental channel features that are in early stages of development. APIs for experimental features have the Experimental attribute. If you call an experimental API in your code, you will receive a build-time warning. All APIs in the experimental channel might have breaking changes in future releases, but experimental APIs are especially subject to change. Experimental features may be removed from the next release, or may never be released.

Important links:

Experimental channel releases:

Version 1.2 Experimental (1.2.0-experimental2)

This is the latest release of the experimental channel. It supports all experimental channel features and features from 1.2.0-preview 1.

To download, retarget your WinAppSDK NuGet version to 1.2.220909.2-experimental2.

Fixed issue

In upcoming Windows Insider Preview builds, applications using Windows App SDK would fail to launch.

Version 1.2 Experimental (1.2.0-experimental1)

This is the latest release of the experimental channel. It supports all experimental channel features.

To download, retarget your WinAppSDK NuGet version to 1.2.220727.1-experimental1.

Input & Composition

First introduced in Windows App SDK 0.8, there are several experimental classes in the Microsoft.UI.Input.Experimental & Microsoft.UI.Composition.Experimental namespaces.

New to this release:

Content

New to this release, the experimental classes in the Microsoft.UI.Content namespace provide the building blocks of interactive content. These are low level primitives that can be assembled into content to provide the interactive experience for an end user. The content defines the structure for: rendering output with animations, processing input on different targets, providing accessibility representation, and handling host state changes.

Notable APIs:

  • ContentIsland - brings together Output, Input, and Accessibility and provides the abstraction for interactive content. A custom visual tree can be constructed and made interactive with these APIs.
  • DesktopChildSiteBridge - enables a ContentIsland to be connected into a HWND-based hierarchy.

Check out the sample on GitHub for more information.

Dispatching

DispatcherQueue now dispatches as reentrant. Previously, no more than a single DispatcherQueueHandler callback could be active on a single thread at a time. Now, if a handler starts a nested message pump, additional callbacks dispatch as reentrant. This matches Win32 behavior around window messages and nested message pumps.

Notifications

Registering app display name and icon for app notification is now supported. Check out the spec on GitHub for additional information.

WinUI 3

  • Controls and styles are up to date with the WinUI 2.8 release.
  • UWP is no longer supported in the experimental releases.

Other limitations and known issues

  • Apps need to be rebuilt after updating to Windows App SDK 1.2-experimental1 due to a breaking change introduced in the ABI.
  • Apps that reference a package that depends on WebView2 (like Microsoft.Identity.Client) fail to build. This is caused by conflicting binaries at build time. See issue 2492 on GitHub for more information.
  • Using dotnet build with a WinAppSDK C# class library project may see a build error "Microsoft.Build.Packaging.Pri.Tasks.ExpandPriContent task could not be loaded". To resolve this issue set <EnableMsixTooling>true</EnableMsixTooling> in your project file.
  • The default WinAppSDK templates note that the MaxVersionTested="10.0.19041.0" when it should be "10.0.22000.0". For full support of some features, notably UnlockedDEHs, update the MaxVersionTested to "10.0.22000.0" in your project file.

Version 1.0 Experimental (1.0.0-experimental1)

This release supports all experimental channel features.

Download

The following sections describe new and updated features, limitations, and known issues for this release.

WinUI 3

This release of WinUI 3 is focused on building towards new features for 1.0 stable and fixing bugs.

  • New features: Support for showing a ContentDialog per window rather than per thread.
  • Bugs: For the full list of bugs addressed in this release, see our GitHub repo.
  • Samples: To see WinUI 3 controls and features in action, you can clone and build the WinUI 3 Gallery app from GitHub, or download the app from the Microsoft Store.

For more information or to get started developing with WinUI, see:

Push notifications (experimental feature)

This release introduces a push notifications API that can be used by packaged desktop apps with Azure app registration-based identities. To use this feature, you must sign up for our private preview.

Important limitations:

  • Push notifications are only supported in MSIX packaged apps that are running on Windows 10 version 2004 (build 19041) or later releases.
  • Microsoft reserves the right to disable or revoke apps from push notifications during the private preview.
  • Microsoft does not guarantee the reliability or latency of push notifications.
  • During the private preview, push notification volume is limited to 1 million per month.

For more information, see Push notifications.

Windowing

This release includes updates to the windowing APIs. These are a set of high-level windowing APIs, centered around the AppWindow class, which allows for easy-to-use windowing scenarios that integrates well with the Windows user experience and other apps. This is similar to, but not the same as, the UWP AppWindow.

Important limitations:

  • This release of AppWindow is currently available only to Win32 apps (both packaged and unpackaged).
  • The Windows App SDK does not currently provide methods for attaching UI framework content to an AppWindow; you're limited to using the HWND interop access methods.
  • The Windowing API's will currently not work on Windows version 1809 and 1903 for AMD64.

For more information, see Manage app windows.

Deployment for unpackaged apps

This release introduces updates to the dynamic dependencies feature, including the bootstrapper API.

Important limitations:

  • The dynamic dependencies feature is only supported for unpackaged apps.
  • Elevated callers aren't supported.

For more information, see the following articles:

Other limitations and known issues

  • No support for Any CPU build configuration: The Windows App SDK is written in native code and thus does not support Any CPU build configurations. The WinUI 3 templates in Visual Studio only allow architecture-specific builds. When adding the Windows App SDK to an existing .NET application or component that supports Any CPU, you must specify the desired architecture: x86, x64 or arm64.
  • .NET apps must target build 18362 or later: Your TFM must be set to net6.0-windows10.0.18362 or later, and your packaging project's <TargetPlatformVersion> must be set to 18362 or later. For more info, see the known issue on GitHub.
  • C# apps using 1.0 Experimental must use one of the following .NET SDKs:

Version 0.8 Preview (0.8.0-preview)

This release supports all experimental channel features.

Download

The following sections describe new and updated features, limitations, and known issues for this release.

WinUI 3

This release introduces critical bug fixes (including those fixed in 0.5 servicing releases) and other changes for WinUI. For a complete list, see the WinUI 3 - Windows App SDK 0.8 release notes.

App lifecycle (experimental feature)

This release introduces new experimental features related to managing the app lifecycle of your app.

  • All apps (packaged and unpackaged) can use GetActivatedEventArgs (although packaged apps can already use the implementation of this in the platform).
  • Only unpackaged apps can use the RegisterForXXXActivation functions.
  • Packaged desktop apps can use app lifecycle instancing.

For more information, see App instancing and Rich activation.

Deployment for unpackaged apps (experimental feature)

This release introduces new experimental deployment features for unpackaged apps. Unpackaged apps can now dynamically take a dependency on the Windows App SDK runtime packages so you can continue using your existing MSI or setup program for app deployment. This is available through the following features:

  • Standalone installer for Windows App SDK.
  • MSIX package bundle that includes dynamic dependencies functionality.

For more more info, see Windows App SDK deployment guide for framework-dependent apps packaged with external location or unpackaged.

DWriteCore

This release adds the following features:

  • Text decorations (underline and strikethrough in the text layout API)
  • Vertical text layout
  • Font face kerning API
  • Experimental support for unpackaged apps

For more more information, see Render text with DWriteCore.

MRT Core

This release adds the following features:

  • The build action for resources is now automatically set, reducing the need for manual project configuration.
  • Experimental support for unpackaged apps.

For more more information, see Manage resources with MRT Core.

Limitations and known issues

  • No support for Any CPU build configuration: The Windows App SDK is written in native code and thus does not support Any CPU build configurations. The WinUI 3 templates in Visual Studio only allow architecture-specific builds. When adding the Windows App SDK to an existing .NET application or component that supports Any CPU, you must specify the desired architecture: x86, x64 or arm64.
  • .NET apps must target build 18362 or later: Your TFM must be set to net6.0-windows10.0.18362 or later, and your packaging project's <TargetPlatformVersion> must be set to 18362 or later. For more info, see the known issue on GitHub.

Samples

The Windows App SDK samples do not yet work with this release. New and updated samples, including samples that demonstrate new features such as unpackaged app deployment, are coming soon.