public static void send(@Nullable final Context context, @Nullable final Integer id, @NonNull final NotificationChannels channel, @NonNull final Function<NotificationCompat.Builder, NotificationCompat.Builder> builderFunction) {
        final NotificationCompat.Builder builder = newBuilder(context, channel);
        send(context, id, builderFunction.apply(builder));
    }
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