When I purchased my J7 it is already updated to the latest software version. There’s two type of battery saver, the new one that comes with the update called ultra power saving mode. If you turned it on, the phone close all application which only allows you to use call, messaging and internet browser application. If you’re asking if it is good, yes it is super awesome.
It is on the side of the brightness screen adjustment. You just need to slide down the option on the top of the screen. From there you will see the brightness adjustment and on the right side of it is the button that you can tab to turn on the outdoor mode.