@luen-12 wrote: Hello I want to know when Windows 10 released the update for the Lumia mobile gophone 640. Thank you .
That depends on your market or how you want to get it. AT&T has not released Windows 10 on any of the Windows 8.x devices. Only phone AT&T has with Windows 10 is Microsoft Lumia 950 which ships wiht it installed. There are some 640's receiving Windows 10 i other markets.
If you want Windows 10 on a Lumia 640 then the best thing you can do is join the Windows Insider program
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