Windows 8.1 is coming along nicely, as just recently the OS reached build 9385. This puts it slap bang in the middle of Milestone 2 and pre-beta development stages, which is good as it means Microsoft are right on track with Windows 8.1 to deliver at BUILD 2013 later this year.
The build is reportedly being distributed to Microsoft Partners on the Microsoft Partner Network. It is currently unclear what this new build includes, however we do know it's a fairly recent one, being compiled on the 12th of April. Bits and pieces of Windows 8.1 have been leaking everywhere lately, we first got our hands on build 9364, and then later saw parts of build 9375 leak. This makes it clear that Windows 8.1 builds are circling outside of Microsoft and Partner walls.
For the techy readers, the full build string reads: 9385.0.PRE_PARTNER_OUT13.130412-2105.