WinSCP should run on any system running Win32 system, which includes Windows 95, up to and including Windows 7. We know of no reason why WinSCP should not continue to work on future versions of Windows.
WinSCP also runs on Linux platforms where Crossover 4.x or later is running. Crossover is the commercial development of the Wine project. WinSCP requires at most 10 MiB of free disk space.