Microsoft has just formally announced the Lumia 640 and 640 XL at their Mobile World Conference 2015 presentation



From Neowin:

The specs include:

5" display
2500 mAh battery
Cyan, Black, White color variations
Single sim, Double Sim variations
3G/LTE
Latest Lumia camera software
8 MP camera, wide angle lens

The 640 XL shares the same specs as above but in a physically larger variation, having a larger screen and larger 3000 mAh battery. The phones will ship with Windows Phone 8.1 but will receive a Windows 10 upgrade.

  Microsoft announces the Lumia 640