While there has yet to be an official release of LineageOS 15.1, the LineageOS developers have been hard at work on the bring-up and several maintainers have released unofficial builds in the meanwhile. The first generation Android One devices, commonly referred to as Sprout within the community, also have a few unofficial builds available. XDA Recognized Developer varun.chitre15 has just uploaded an early alpha build of LineageOS 15.1 that brings Android 8.1 Oreo Go Edition to these devices.

Android Oreo Go Edition is a special build of Android 8.1 that is optimized for low-end devices. It is essentially comprised of some special build configurations and Android Go-optimized applications, which means that custom AOSP ROMs can incorporate Android Go's optimizations into their ROMs.

Since this is not an official build and is still in alpha stages, we are to expect that some things may not work and some bugs to surface on occasion. So far, we're told that the camera doesn't work and that cellular calls and data can be buggy from time to time, but the rest of the build is quite stable.

Download unofficial LineageOS 15.1 based on Android 8.1 Oreo Go Edition for Sprout