To get the device settings time change notification, i found that we have to use UIApplication.significantTimeChangeNotification notification and func applicationSignificantTimeChange(_ application: UIApplication) delegate method.
But in my case even though if app in background or in killed state, then i have to show local notification to the user saying that device time is changed. Is it possible, Please let me know if we have any solution for this.
From Apple Document on applicationSignificantTimeChange
If your app is currently suspended, this message is queued until your app returns to the foreground, at which point it is delivered. If multiple time changes occur, only the most recent one is delivered.
So, it clearly conveys that this will work only when the app is in Foreground. It is not even queued up when the app is not running.
To display any local notifications when the app is not running, it should be scheduled in the past to trigger it in the future. And it is not possible for the app to know about the time change event when it is not running. It looks like you would not be able to achieve what you have asked.