Infamous Microsoft leaker WZor has come out hiding and dropped some interesting information regarding to Windows 8.1 Update 2. Here is a roughly translated Russian quote from WZor:
At this time I cannot give an exact date of signing of the RTM. Although next week (23 – 27 June) a very significant event is planned inside Microsoft.I’m not sure what will happen, but most likely the first RTM-Escrow build will be signed off.
The timing makes sense as Microsoft typically gives OEMs one to two months to prepare their new hardware following RTM. This means we will likely see general availability of Windows 8.1 Update 2 by August. In the meantime Microsoft will work on QFEs (quick engineering fixes) to solve specific problems.
What remains unknown is what exactly is inside Update 2. The start menu has been pushed back to Windows 9 (‘Threshold”). The rumors is that it is likely to contain software optimizations and fixes so that Windows 8 will work better on devices with small form factors. The Surface mini is expected to launch soon after the release of Windows 8.1 Update 2.
Source: Ru Board