When Microsoft unveiled Windows 10 for phones last month, it claimed it would be available for all Lumia handsets running Windows Phone 8.1. Since then the company has backtracked a bit on those promises, and now we know a bit more about Microsoft’s mobile upgrade plans.

According to Microsoft exec Joe Belfiore, the company is working on a scaled back version of Windows 10 for devices with less RAM, including the best-selling Lumia 520.

The news doesn’t come as a huge surprise. Still, it’s better than nothing, and hopefully this low-end version of Windows 10 doesn’t leave out too many important features.

Belfiore also notes that the first Windows 10 for phones beta test will be available for a “subset” of devices, so we may get a look at the scaled-back software before too long. The company had originally promised sometime in February. It seems likely Microsoft will focus on more flagship devices, such as the Lumia 930, at first.

The first official preview is expected to arrive later this month, so we should know more pretty soon. For now though, it’s probably not worth buying a low-end Lumia handset if you’re hoping to try out Windows 10.