Lenovo
We’re still gathering more info on battery saving features on Lenovo devices.
Lenovo P2
Lenovo P2
Lenovo P2 has a very good battery life, but at a cost.
For an app to work in the background:
Enable the padlock icon at an app in the right top corner in the overview of running apps. It’s only then actually running as a foreground process. If you swipe it away, its background process will be killed mercilessly.
It does not matter if the battery/power optimization is “On” or “Off” in Settings > Apps > Your app > Battery.