Yes, QuickShadow Backup is tested and supported on Windows 8 & 8.1 & 10, in the desktop environment.
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It is unlikely that QuickShadow Backup will be modified for the Metro/Modern user interface.
It is unlikely that QuickShadow Backup will ever be ported or supported on devices using only the (cut down) WinRT version of Windows 8 (for example, tablets on ARM processors).