VMNotifier is an Android app, running on 4.2+ (Jellybean), which notifies you of new voicemail by periodically playing your Notification tone and displaying a brief note. VMNotifier uses these permissions:
You may adjust the notification interval by minutes (1-60). Setting the interval to 0 will use the default value of 15 minutes.
After checking all voicemail and no new voicemail exists, VMNotifier’s notifications may continue under some conditions. The precise conditions vary and are artifacts of your service provider’s voicemail system. The Reset button will reset VMNotifier as though there were no new voicemail.