No need make Fopnu client open source, this a dev option, but need make the network open source, so others can make new clients, for android, iOS , mac, linux, windows etc, and the network can survive for ever like the bittorrent. As is today Fopnu network haven't any future, is like Soulseek network, is just a question of time to these networks die. So no need open source client, but is essential a open source network.