Unnamed sources have informed ZDNet that Microsoft plans to distribute Windows 8.1 Update 2 on August 12, which is this month's Patch Tuesday. They are also reporting that this update won't be a big deal like Update 1, but will be pushed like any other distributed update. Most importantly, Update 2 will not be a mandatory install.
The report states that Microsoft originally planned for Update 2 to be bigger than it is now and include the new "mini" Start Menu, but the team decided not to include the Start Menu just months ago. It will cram the new Start Menu into Windows "Threshold" (which is currently still called Windows 9) instead, when it launches in Spring 2015.
These same sources tell ZDNet that another Windows 8.1 Update will be highly unlikely; Microsoft plans to toss everything into the Windows Threshold release instead. Rather than unleash a fat update, the company will distribute small monthly fixes and updates until Windows Threshold is released.
Previous rumors claim that Microsoft planned to release Update 3 sometime in Q1 2015. There have also been reports that Microsoft may launch a public preview of Windows Threshold in Q4 2014, although that may actually be a developer preview instead.
Currently, despite the recent leaks, Microsoft isn't saying anything about the Threshold release. Instead, there are rumors that Microsoft may actually provide Threshold for free to Windows XP, Windows Vista and Windows 7 customers. That backs up previous rumors that the new platform will possibly be free to Windows 8.1 customers. Why? So that these customers are on a newer, more secure platform.
So what's going to be in Windows 8.1 Update 2? ZDNet's sources report that it won't be cumulative, and will include minor design changes. We will probably find out the closer we get to August 12.