Check if the user enable the Notification on iOS 8, iOS 7, or less

check-notification-status.m

NSInteger activePush = 1;
if ([application respondsToSelector:@selector(isRegisteredForRemoteNotifications)]) {
    activePush = ([application isRegisteredForRemoteNotifications]) ? 1 : 0;
}
else {
    UIRemoteNotificationType types = [[UIApplication sharedApplication] enabledRemoteNotificationTypes];
    if (types == UIRemoteNotificationTypeNone) activePush = 0;
}