It's looking very much like Microsoft is close to the end of its main Windows 8.1 development, if recent leaked builds of the OS and screenshots are to be believed. Microsoft has already announced it plans to offer the RTM build to OEMs sometime in late August.
The usual custom is that Microsoft would then allow subscribers of its MSDN and TechNet services to get early access to the next version of Windows before it is released to the general public. In 2012, Windows 8 hit the RTM stage on August 1 and was available from the MSDN and TechNet channels two weeks later on August 15th.
However, ZDNet's Mary Jo Foley reports, via unnamed sources, that Microsoft could decide to do things a little differently and hold off on offering Windows 8.1 for everyone until mid-October or so. The story speculates that Microsoft might try to use the time to stamp out some bugs between the RTM stage and the general availability date. It could also make a Windows 8.1 launch more dramatic than the one in 2012 for Windows 8, as many tech enthusiasts had already had a chance to play (and loudly voice 'concerns') with the OS for a month beforehand.
This report, which has yet to be confirmed by Microsoft, comes even as it is shutting down its TechNet service. The company announced recently it will stop taking new or renewed TechNet subscribers after August 31st. Microsoft has said it will continue to honor all current TechNet subscriptions until they conclude.