Windows Blue is Windows 8.1, Coming This Summer

Windows 8 may not have been the kind of runaway success Microsoft had bargained for, but the company isn't sitting around to release its service pack. Reliable sources told ZDNet that "Windows Blue," codename for an unreleased Windows build doing rounds with Microsoft's industry partners, could be a new RTM product bearing the commercial name "Windows 8.1," and not Windows 9, as was previously reported.

A screenshot of an early build of the software, running Windows NT kernel 6.3 (Windows 8 runs 6.2), and a bearing a build number 9375, was posted by Roman L. (a k a @AngelWZR) of, on Twitter. "Well, maybe that's not an April Fools' joke," AngelWZR tweeted.

Another source told ZDNet that top-level-branding of the software will remain "Windows 8," with a version number change to 8.1. It remains to be seen if Windows 8.1 is a version current users of Windows 8 have to pay, to upgrade to. Another theory doing rounds says that Windows 8.1 could be another way of branding "Windows 8 Service Pack 1," following the version scheme of Microsoft's Windows Phone mobile software. The company recently released Windows Phone 7.8 to succeed 7.5, even as the company counts both as part of Windows Phone 7.

Windows 8.1 could, according to ZDNet, release to manufacturing (RTM) as early as this summer (by September).