And, again, as those same sources have said, Microsoft won't be making a big deal out of this next update.
Update 2, to which Microsoft will be referring as the "August update," won't be mandatory, unlike the first Windows 8.1 Update. It also won't be cumulative. It'll be pushed as just another monthly update to Windows 8.1. It will include some relatively minor design changes, I hear, but nothing big, feature-wise.
Microsoft's original plan was to make this update a much bigger and more important release. The Windows team originally was aiming to make the new "mini" Start Menu part of this second update, but scrapped that plan a couple of months ago, deciding instead to make the new Start Menu a feature of Windows "Threshold." Threshold, likely to be called Windows 9, is still sounding like a Spring 2015 deliverable.
From what my sources are saying, Microsoft is unlikely to deliver a third update to Windows 8.1 later this fall. There are some who believe the company could opt to deliver one more update to Windows 8.1 that would include some new features, possibly this fall. (The idea in doing this would to be to establish a "servicability" cadence pattern.)
But others said the operating systems team is leaning toward putting all the wood behind the Windows 9 arrow, while continuing to deliver small monthly updates and fixes to Windows 8.1 until Windows 9/Threshold arrives.
Microsoft officials are still not talking publicly about Threshold/Windows 9. There are rumors Microsoft is planning to offer Windows XP, Windows Vista and Windows 7 users some kind of deal — possibly even a free upgrade to Windows 9 — in order to get them to move to the latest Windows version once it's out next year.