Need for VS2015 support
When "Qt for Windows (VS 2015)" and "Visual Studio 2015 Add-in" will be released ...
Qt compiles and works with VS2015 for at least couple of months now. 5.5 has a mkspec for it so you can compile it if you need to.
If you mean a precompiled binary (and the add-in) then this question is better suited for the mailing lists where the Qt devs hang out. This forum is used mostly by Qt users. We don't make schedules here.