… And it is the 29th July.
http://blogs.windows.com/bloggingwindows/2015/06/01/hello-world-windows-10-available-on-july-29/
But there is still no news whether App-V 4.6 will be officially supported on Windows 10 as mainstream support will end on 14th july (which probably means no further service packs for App-V 4.6 ).
At least it seems to work from technical viewpoint according to Tim Mangan from BrianMadden.com .
Regards,
Fabio