Microsoft released Windows 10 Insider Preview Build 16288 to Fast ring members of the Windows Insider Program. This release, like the preview builds released in August, are meant to help the company put the finishing touches on the Windows 10 Fall Creators Update for its October 17 debut.
Preview Build 16288 includes a long list of bug fixes to the Windows Shell, Microsoft Edge, and various input methods, among other things. Microsoft also fixed a couple of game-specific issues that prevented Ghost Recon Wildlands from launching and The Elder Scrolls V: Skyrim mods from loading. Those fixes will complement Microsoft's efforts to combat frame rate stuttering issues some people noticed with the Windows 10 Creators Update.
Other changes range from quality of life improvements, like fixing a bug "where upon unlock you’d be bombarded with any notifications that occurred while your PC was locked," to more serious problems like Windows Store apps failing to activate after being launched a few times. So even though there aren't any flashy new features to show off in Preview Build 16288, its changes will probably be welcome all the same.
Still, Microsoft isn't done with the Windows 10 Fall Creators Update just yet. The company made that clear in its announcement:
On Build 16288, you will notice that the watermark at the lower right-hand corner of the desktop has disappeared. You will also see that the OS now reports as “Version 1709” which is the official version number for the Windows 10 Fall Creators Update release. However, this is NOT the final build as we’re not done yet. We’re just now beginning the phase of checking in final code to prepare for the final release. So we will have more builds to release to Windows Insiders between now and then. And the desktop watermark may re-appear in these builds.
Surprisingly enough, Microsoft actually made some more interesting changes to Build 15250 for Windows 10 Mobile. That build also includes various bug fixes, of course, but it also brings with it several new features. All three of the changes introduced with this build—a new two-factor unlock system, refined UI for AppLocker, and VPN improvements—center on making Windows 10 Mobile devices more attractive to enterprise customers.
Each update is pretty much what you'd expect. The new two-factor unlock system requires people to enter a numeric pin and use a second "enterprise-defined factor," such as an NFC tag, whenever they want to unlock their phone. The AppLocker update makes it clearer when an app is blocked due to enterprise policies. VPN support will also be more reliable, secure, and convenient thanks to Microsoft's grab bag of improvements.