public static void send(@Nullable final Context context, @Nullable final Integer id, @NonNull final NotificationCompat.Builder notificationBuilder) {
        getNotificationManager(context).notify(id == null ? Settings.getUniqueNotificationId() : id, notificationBuilder.build());
    }
A fresh not yet used notification id can be gathered via {@link cgeo.geocaching.settings.Settings#getUniqueNotificationId}
main/src/main/java/cgeo/geocaching/ui/notifications/Notifications.java