This is another step towards Microsoft moving away from Universal Windows Platform (UWP) and marrying Win32 support. Instead, the company is looking for a blanket Windows experience that will be sent out under “Windows apps”. You can see how this will play out in the image above, with WinUI 3.0 encompassing Win32 and UWP across form factors. At first, WinUI 3.0 alpha will be available to Insiders for testing. Microsoft will make the platform available as an open source on GitHub. However, a full preview of the platform will not be made available until the first half of 2020.
— Ginny Caughey (@gcaughey) October 30, 2019 WinUI 3.0 alpha will begin on UWP, according to enterprise software developer Ginny Caughey (@gcaughey on Twitter). Windows 10 UI will now be separated entirely from the UWP software development kit (SDK).
Single App Experience
So, if you are a developer who wants to build a new app on Windows 10, you be able to use Win32, UWP, .NET Core, or C++. Other frameworks will be added in time, meaning Windows dev’s will have much more choice. Earlier this year, Microsoft detailed its roadmap for merging UWP and Win32 for a unified app experience. Its XAML Islands v1 lets .NET and Win32 apps host UWP XAML controls. Microsoft is planning to roll out the Windows Community Toolkit v6.0 this summer, bundled with the WindowsXAMLHost and wrapped controls for .NET. A 6.1 preview will also launch, which will include the .NET Core 3 version and launch in the second half of 2019.