At MWC earlier this year, Microsoft introduced its two new latest Lumia smartphones, the 640 and the 640 XL. Earlier, we took the Lumia 640, available on Cricket Wireless, for a spin. Now, we're hearing about its larger sibling. The Microsoft Lumia 640 XL is also coming to the US, but it will be an exclusive offer from AT&T. Mixing a large phablet screen with rather low specs, the Lumia 640 XL is yet another addition to Microsoft's growing number of almost indistinguishable Windows Phone models.