How to update your Nokia Lumia 520 625 820 1020 1520 to windows 8.1

 Windows 8.1 is very expected for the Nokia  Lumia 520 625 1520 and all others especially for the new digital assistant Cortana that is expected to match or surpass the Apple personal assistant Siri. There are other new interesting features available on the new Windows 8.1, like the “Project [...]