Wow, this one caught me by complete surprise. LineageOS – an alternative free and open-source operating system for mobile devices – have just officially released version 15.1 of their OS for the NVidia Shield Tablet K1. LineageOS is a fork of the once-popular CyanogenMod and version 15.1 of the OS is based on Android 8.1 (Oreo) Nvidia Shield Tablet K1 The Shield K1 is – in my opinion – one of the best Android tablets available.