I'm wondering if their iPhone application needs to remain in foreground/active in order to receive notifications? I doubt it because it would be a quite big sho

I'm wondering if their iPhone application needs to remain in foreground/active in order to receive notifications? I doubt it because it would be a quite big shortcoming but on other hand given the state of third-party 'multitasking' on iOS I'm not sure it is technically possible without it. Anybody wants to chime in?