This release of Sailfish OS 2.1 is based on CyanogenMod 13 sources. A pre-alpha build is available for users to install. Since it is a pre-alpha build and very much a Work-in-Progress, bugs are expected. What works in this build is basic features like booting into the GUI, Display, Touchscreen, Sound, Vibration and RIL. You do need to flash a CyanogenMod 13 build before flashing the build, and also need to flash the developer’s kernel.