ZD Net reports Windows 8.1 has hit RTM phase on August 23rd. Microsoft declined to comment but according to Paul Thurrott from SuperSite for Windows the final RTM build number is 9600.16384.130821-1623. The site speculates Microsoft opted against announcing Windows 8.1's RTM on Friday so the news wouldn't be overshadowed by the announcement of CEO Steve Ballmer's retirement sometime within the next 12 months. Public availability of Windows 8.1 is expected to arrive by October 18.
I talked to another contact of mine who said the internal RTM e-mail made the rounds inside the Windows division on August 23. A third source close to the company confirmed Microsoft RTM'd Windows 8.1 on August 23, and announced internally that the quality metrics for Windows 8.1 were back in line with those of Windows 7. (The vast amount of changes in the Windows 8 code base resulted in an increased number of crashes and hangs for Windows 8, one of my contacts explained.)
I asked a Microsoft spokesperson if Windows 8.1 RTM'd on August 23 and was told the company had no comment.
Microsoft may have opted against announcing Windows 8.1's RTM on Friday so that the news wouldn't be overshadowed by the announcement that CEO Steve Ballmer is retiring some time within the next 12 months. As I blogged previously, my sources said Microsoft was targeting Monday August 26 as the day it would RTM Windows 8.1.