Microsoft has already stated that it will be delivering a new build of Windows 10 in January, dubbing the new build "FBL_AWESOME." The new build will release as part of the communicated January "event" where Microsoft will take the wraps off some new features for Windows 10, and potentially new directions for Windows 10 on tablets, smartphones, and other devices.
We've seen a few updates filter through for Windows 10 this month already, but those were designed to fix problems with build 9879 before Microsoft headed out into the holiday sunset. But, today, Microsoft is delivering one last update for the year (possibly the last – who really knows at this point). This one, labeled KB3025380, is delivering now and is intended as preparation for the January build release. Without it, FBL_AWESOME won't install.
As usual, Gabe Aul, Windows Insider czar, announced it on Twitter…
Hi #WindowsInsiders - one more WU update today. This one preps your system to take the next build from FBL_AWESOME branch.— Gabriel Aul (@GabeAul) December 18, 2014
The update should already be available through Windows Update, but if not, just keep checking. It's rolling out today.