Updating ATT Lumia 640 from Windows 8.1 to Windows 10

[Leo Nicholson]

Can you update the OS with a phone that is not activated by carrier, but only used for wifi?

 

[PepperdotNet]

Yes indeed. Windows phones are fully functional without a SIM card, except for being able to make phone calls and text messaging of course.

And I can say from personal experience that the 10586 builds are fantastic on a Lumia 640.

 

[gordonfink]

Yes - use the Windows Insider Program.

 

[mjrtoo]

I agree, I have the 640XL on 10 and it's quite pleasing. Great mid range phone.