Like so: If the app isn’t optimized for Oreo, you’ll have a second option: Background Activity. By default, this toggle is set to “On”, which allows the app to run in the background when you’re not using it.

What does allow background activity mean?

Allowing background activity just allows an app to do just that: work on the background when you’re not actively using it.

Is it OK to restrict background activity?

Starting with Android Oreo, you can prevent an app from running in the background, thereby preventing it from using up precious battery life.