In a comment on its official Lumia Page, Microsoft has said that they will be rollong out Windows 10 Mobile to existing Windows Phone devices starting in December.
Lumia 640 and Lumia 640 XL will be the first few devices getting updated to Windows 10 Mobile. Microsoft has further added that only devices with 8GB or more internal storage will be updated to Windows 10 Mobile and that not all features will be available on every device.
However, the company remains committed to rolling out Windows 10 to all compatible devices running Windows Phone 8.1 with Lumia Denim update.
There was no timeline mentioned for the rollout but given the vast number of Lumia devices in the market, rollout will be gradual.
Source: Facebook
