Just make your own fan-copy of rotmg as a mmo in Unity. Using old sources, is no good in the long lane, not even Nilly's source, even though it is stable. Every single rotmg private server source we have available theese days have issues all the time. You could, make your own source, or optimize the deca client and fabiano swagger of doom server, but there is a reason DECA is going to use Unity for realm in the future.