The app will not work when you have power saving modes turned on. The device takes complete control of those backlights in that situation.
Added a day/night theme for Android 6+ devices so the interface will get dark at night. Added a material compliant icon as well. (This may break when it goes to Android N, but only time will tell!)
A new version was required due to Android permissions issues compiling against SDK 23.
It has been tested on Verizon models of Tab S2, S6 Edge, S7 Edge, and Note 7. I'll add other confirmed devices after people comment about them.
The app will not work on non-Samsung devices or on Samsung devices that don't have backlight buttons. The Galaxy Tab A line is an example. Those devices have no lights to turn on or off. The app will not work with custom ROMs. It has to be a standard Samsung ROM for the app to control the lighting.
App does NOT require root. It requires permission to write system settings so the changes can be saved. You will need to set back to Default in the app if you want your original timing. Uninstalling the app alone will not revert it.
NOTE: Please submit bug reports if you see a crash or send an email if something isn't working as intended. That is the only way I can try and fix things for you. Thanks!