The Register reports Microsoft's Julie Larson-Green stated at a recent investor event that having three versions of Windows is too many. She didn't give any exact details about what the software giant plans to do about this, but it seems highly probable that Windows RT and Windows Phone will be merged in the near future. Larson-Green did mention that she sees the need for one full Windows and one more mobile Windows that is more locked down.
But what we can sensibly infer is that Microsoft appears to be on a path to merge Windows RT, the subset of Windows that runs on ARM hardware, with Windows Phone, which now runs on the NT kernel and is highly portable, but runs on ARM. According to reports, only 33 per cent of the Windows Phone and Windows RT APIs are compatible today, although the goal for the next major update, "Blue", is to reach 77 per cent compatibility. According to Mary Jo Foley, full compatibility wouldn't be reached until 2015, which is still some 13 months away.
While RT is the more sophisticated API, Windows Phone appears to be winning the internal political battle, with stories suggesting it has been freed to scale up to 7-inch and 10-inch tablets.
Larson-Green reiterates the need for one full Windows and one more mobile Windows that is more locked down (the politically acceptable phrase is "turnkey", by the way).