Finally, after waiting for long AT&T released Windows 10 mobile official update for Lumia 640 users. Its been some months, Lumia 640 users under AT&T waiting for the update. Finally the dream fulfilled. As per the reports by users in AT&T forum,Windows 10 mobile update is now rolling out to Lumia 640 devices.
Windows 10 Mobile is officially rolling out to Lumia 640 on@ATT AND Lumia 735 on @Verizon! Stay tuned for deets: https://t.co/UJCdpv7Ojq
— Dona Sarkar (@donasarkar) June 3, 2016

You need to use upgrade adviser app to receive the update. If you are using an AT&T Lumia 640, you can download the official Windows 10 now on your handsets.
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