A few days ago, the smartphone company Yezz stated that all of its current Windows Phone device would be able to get an upgrade from Windows Phone 8.1 to Windows 10 Mobile. Now the company has reversed course somewhat, stating that its 4-inch Billy 4 smartphone would not get the Windows 10 Mobile update after all.
According to Windowsblogitalia, the reason Yezz gave is a bit odd. Basically, the Billy 4 has 4GB of onboard storage, but a Yezz spokesperson claims the Windows 10 Mobile upgrade would require that the phone have 8GB of onboard storage. Yet, Microsoft's own hardware documentation for Windows 10 Mobile states that a smartphone can have as little as 4GB of onboard storage. It's possible that there is something else storage-related on the Billy 4 that is keeping it from getting the upgrade.
Yezz is still indicating it will release new devices with Windows 10 Mobile in the future but there are no other details on those plans.