I made a library that enables client-server communication using both TCP and UDP protocols. When game developers on the #gamedev IRC channel (Freenode) knew that, they totally refused the idea. They recommended RUDP instead of TCP. Should I remove the TCP communication and use RUDP instead?
RUDP is a very exotic non-standard transport-layer protocol which is not supported on any mainstream networking hardware or operating system.
However, there are libraries which implement protocols on top of UDP which have additional TCP-like reliability features but still fulfill the requirements of real-time games. One such library is ENet. The Unity engine also does something similar when requested.
But TCP should not be totally dismissed for game development. Sure, it is unsuitable for real-time games where latency matters, but it is still a very useful protocol for turn-based games.