Increasing the player limit would cause more desyncs, bust mod compatibility, mods with 16 hardcoded spawn points would break, and port more strain on the host. So the game couldn't really handle a higher player limit.
It's not that there isn't any solution to the problem, but it would be very hard to make a higher player limit and a lot of mods would need major updates.
MAX_PLAYERS constant to be 20 in the source code, or whatever number you want. Syncing may or may not break. In order for players to join the lobby, you'd need to have them also have the max players constant changed.
While true, moderation recommends against modified builds. It's a "fair play" precaution more than anything-- if you really need to, keep it private, and don't use it on CoopNet.
So if I am going to make a mod with a higher player limit then 16, then it has to be private?
Regardless, CoopNet has a hard coded limit of 16. So even if you do modify your build to do that, your lobby will still only allow 15 other players. So if you do want to play with 20 players, you have to use direct connection.
Wow, I know a bit of code, so is it possible to make servers of 20 right now?
Well, the game is hardcoded to limit amount players to seven so even if you did change the code to alter the player limit, it would remain sixteen players only.
