Microsoft is still offering Windows Insider members new automatic updates to the current 9879 Windows 10 preview build. Today, they should see the latest update to the OS, with this one preparing Windows 10 for the next major "awesome" build release.
As posted by Microsoft's Gabriel Aul on his Twitter account today, "Hi #WindowsInsiders - One more WU update today. This one preps your system to take the next build from FBL_AWESOME branch." As he revealed in a blog post on Wednesday, the "FBL_AWESOME" build will be the next major update to the Windows 10 preview. It should add a number of new features to the OS, and its due for release sometime in early 2015.
A leaked 9901 build made its way onto the Internet a few days ago, but we would not install it on your PC, as it will prevent Windows 10 from getting any future automatic updates from Microsoft.
Source: Gabriel Aul (Twitter)