Microsoft is currently developing the next major version of Windows, currently known as Windows Threshold or Windows 9. We've been tracking development via a user on Twitter, who constantly watches app logs to check for new build numbers. Today, Stealth2013 has spotted the first Windows NT 6.4 build, which means Windows Threshold is going to bring yet more improvements to the NT kernel.
Today's build is 9788, and other than the NT version number we don't know much else about the build. These are not full build strings sadly, which means we are unable to determine when the builds were compiled or what lab they were compiled in. What this does tell us though is that Microsoft are constantly compiling new builds, and that even more kernel changes are in the pipeline for Threshold.
Much like every major version of Windows, the NT kernel is usually bumped by x.1 or even a whole version. The jump from Windows XP to Vista saw the NT kernal rise from 5.1 to 6.0. Windows 7 was 6.1, Windows 8 was 6.2 and Windows 8.1 was 6.3, so Windows Threshold could have either been 6.4 or 7.0. It seems Microsoft went for the minor bump instead of the larger increase.
We recently heard about how Threshold was going to act for both desktop and tablet users, with a Start Menu taking center stage for users without touch, and an improved Start Screen for tablet users. We'll update you accordingly when new Threshold information arrives, so stick around at WinBeta until then.