Fine, I'll say fixing and adding. Not sure if you're aware, but adding things usually breaks other things.
Servers break when you add mods to existing worlds.
Asking users to use an "other than recommended version" of a modpack makes running the server difficult, due to confusion.
Asking users to use an "other than recommended version" of a modpack means tech support can't help.
Come on thats absolutly not true, I actually do have my own server which I use for myself, it has been running 1.64 for over a month and during that time I have added many mods and none of them have broken my server.
I guess we shall agree to differ on this as we could go round in circles for ever