See also: Is there any way to write a WinRt (Metro) app that will also work on Windows 7 and Vista?
I am trying to understand how to target both Windows 8 on Arm and
Microsoft has made no statement about whether or not desktop apps will be supported on Arm processors. They have shown Microsoft Office running, but have not said whether that will be supported on the final platform.
For now the only statements have been about Metro style apps and those will be supported written in any language.