Local Notifications were also ones I thought of. However, the way I understand, Local Notifications are permission based. User must grant the necessary permission. This is not the case in Apple's Stopwatch or in Alarm or in Timer. It is a competitive disadvantage. How can I build a customized timer the way Apple implements? I don't see any functionality within the iOS SDK.

Thanks a lot for the response. Does this architecture "retry" a notification if it cannot deliver the message in the first try?

This is very weird, that should be some law requiring them to provide such list. As an app provider, how would I know otherwise that somebody bought the app or not?