Screenshots of Windows 8 build 7989 have surfaced on the BetaArchive forums (via Neowin). The full build string is "7989.winmain.110421-1825.615974c7346f7374" meaning that this build was compiled at 6:25PM on April 21, 2011.
The screenshots show a new background and boot screen, but other than it's not clear what else is new. For that, we'll have to wait to see if the build leaks out in full. That may happen, according to a user who goes by the name of Smorgan: "Will it Leak: Check back in a few days..." As always, we must emphasize that this is still very early in Windows 8's development, so try not to start forming your opinion on the OS just yet.
Windows 8 build 7850, the first leaked Windows 8 build, hit the Internet two months ago. It was quickly followed by Windows 8 Build 7955 a few weeks later. Last month, Windows Server 8 build 7959 leaked, and then everything went quiet.
A week later, Microsoft was rumored to have fired two employees for the leaks. We heard next to nothing for a month, other than the fact that the build numbers had quietly passed the 8000 mark. Personally, I'd love to see a new build (though not necessarily this one, since it's so old) but I don't want to have anyone lose their job over it.
Although a rumor suggests that Windows 8 will arrive on January 7, 2013, we expect that the operating system will ship in time for the 2012 holiday season. In fact, Microsoft CEO Steve Ballmer has said Windows 8 is coming in 2012, but Microsoft quickly claimed this was a misstatement.