For months, dedicated fans have been discovering new icons for the built-in Windows 10 apps, but they actually haven't been available yet. The only time most of them have really been available to the public is if you installed the Windows 10X emulator, but now, they're making their way to Windows Insiders in the Fast ring.
First spotted by Aggiornamenti Lumia, the apps getting the new icons include Mail and Calendar, Calculator, Groove Music, Movies & TV, Alarms & Clock, and Voice Recorder. Most of these icons had been spotted at some point over the past few months. It's not just the Fast ring that's getting a glimpse of these new icons though. Mail and Calendar are actually getting updated for Insiders in the Release Preview ring, bringing along the respective new icons.
Of course, there are still a lot of apps that haven't received redesigned icons yet, even though we've seen them. Camera, Weather, Snip & Sketch, Maps, and many others have already been spotted. Now that they've started making their way to the public, though, maybe it won't be long before more apps follow suit.
Microsoft's goal is likely to have these icons ready for the launch of Windows 10X, so they should be available to Insiders at some point before then.