Qt 5.2 is tentatively planned for release in November and among its work will be early features needed for KDE Frameworks 5, full Google Android support, full Apple iOS support, improved Wayland support, and other changes and features.
Oliver Wolff of Digia confirmed on the Qt development list today that they're latest platform target to support by Qt5 is WinRT. They hope for at least the WinRT port in Qt Base to be merged in early September ahead of the Qt 5.2 feature freeze.
WinRT is the Windows Runtime platform architecture of Windows 8 and works on both x86 and ARM architectures. WinRT is used on Windows 8, Windows RT/ARM, and WIndows 8 Phone. Update: cleared up confusion about Windows RT / WinRT.