Microsoft is running a public preview program for its next operating system. It recently released a new Windows 10 for Phones build which brings support for many existing Lumia devices. When the beta program started only a handful of Lumia devices were compatible with Windows 10 for Phones. Even though the Lumia 640 is included in the list there are some units that won’t be able to run the preview software.
Some of the devices that still haven’t made the cut include the Verizon-exclusive Lumia Icon and the Lumia 930. These devices were left out due to an issue with user interface scaling.
Lumia 640 is among the many mid-range devices that are compatible with the preview builds but Microsoft now cautions users that some units may not be able to work with Windows 10 for Phones.
The company writes on its Community support site that if someone has a Lumia 640 handset running Windows Phone 8.1 with OS version greater than 8.10.15116.125 they will not be able to upgrade to Windows 10 for Phones preview currently.
It’s possible that this is the same issue that caused Microsoft to halt the roll out of preview builds for Lumia 520, Lumia 525 and the Lumia 526. The company then released an update for the Windows Phone Recovery tool before these devices were able to get on Windows 10 for Phones.
Microsoft may do something similar for the Lumia 640 to ensure that all units are able to run with preview builds of Windows 10 for Phones.