Confirmed: Windows Blue will be called Windows 8.1By Zac on Tuesday, Apr 2nd, 2013 at 06:43AM
A screenshot of Windows Blue build 9375 leaked onto the internet yesterday, revealing a rather interesting change in the naming of the OS. In the system version window, we could see a string of text that said 'Windows 8.1 Pro'. Of course, since yesterday was April 1st, many didn't believe the screenshot to be true, it turns out it is.
Maro Jo Foley from ZDNet says "the top-level branding will be "Windows 8" when Microsoft releases the 8.1 update". This is similar to how Windows Phone does it. First we had Windows Phone 7, then 7.1, 7.5, 7.8 and finally 8.0.
Build 9375 of Windows 8.1 reportedly includes a new PC settings tile, much like the one that was included in the Windows Developer Preview back in 2011. Not much else has been said about the build.