title: How can a iOS app push a local notification after killed when the wifi and cellular is closed?
body: <p>I discover an app, called 2n mobile key. I have some doubts about this app. First, I close the wifi, cellular, and switch on the Bluetooth, then I open the app, everything is fine. And then, I kill the app, and open the control center, close the Bluetooth, I got a local push(I have closed the wifi and cellular). I don't know how the app can push the local notification. I doubt the app isn't killed, it is still alive in the background. But, how can it do it?</p>