The ZTE Axon 7 and the LG G2, in particular, are two old devices now, releasing in 2016 and 2013 respectively. Even still, old age has never been a deterrent to some of the most talented developers on our forums, and it’s no different even now. You can now get an official build of LineageOS 15.1 for both the ZTE Axon 7 and all variants of the LG G2. That’s not all though, as both the lower-end Xiaomi Redmi 3S/3X and the Xiaomi Redmi 4X are also getting an official build of LineageOS 15.1 as well.
With a lighter system footprint than ZTE, Xiaomi, and LG’s stock ROM as well, you’ll likely get much better performance. Either way, it’s currently the only way to get Android Oreo on the LG G2, Xiaomi Redmi 3S/3X, or Xiaomi Redmi 4X. The ZTE Axon 7 has a leaked Android Oreo beta you can install that came out when the company was feared to effectively shut down. If an open, stable system with some extra features is what you want, then you definitely can’t go wrong with LineageOS 15.1.