Microsoft would obviously love it if developers fully embraced its Universal Windows App (UWP) platform and focused entirely on building apps for Windows 10. We will just have to wait and see how things ultimately play out. In the meantime, Microsoft is rolling out a new way of testing app updates in Windows 10, one that could vastly alter the Windows Insider program as it is currently constructed.
According to Thurrott, Microsoft has begun testing a new preview program for a handful of core Windows 10 apps, including Windows Camera, Microsoft Photos, Alarm and Cloock, Feedback Hub, Tips, and a few others. Microsoft is calling the new program Windows App Previews, and at least for now, this appears to be separate from the Windows Insider program. It's comparable to users can beta test early builds of Android apps from Google's Play Store, only for Windows 10.
Microsoft has been sending out invites to select users to join its preview program.
"You'll be one of the first to try out new features in the preview version of Camera, and your feedback will help shape the future of the app. Before you join, please read the review preview program details," Microsoft's invitation to a preview version of its Windows Camera app reads.
One thing that is interesting here is that Microsoft has not mentioned is apps preview in its Windows Insider program. This could indicate that Microsoft wants its app previews to exist outside of the Windows Insider program. The benefit to users is that they could test individual apps of interest without also having to commit to a preview build of Windows 10.