iOS neither has true background apps nor a true history. When clicking a link that opens Safari (for example), the originating app only knows its shutting down

iOS neither has true background apps nor a true history. When clicking a link that opens Safari (for example), the originating app only knows its shutting down and in the future may be restarted. The only decision to be made is "Save state or not?" .. the double-click-on-home method to go back to the last app works pretty consistently if apps save state, primarily due to simplification of options. It sounds like Android, on the other hand, has real background apps and a real history. If so, the back button would then actually have to communicate a state of some sort to the previous app (which is still running), putting the end action in the hands of the developers.