@Seirdy
Quoting Prosody devs

"MUC has some fundamental architectural issues that MIX aimed to fix, but we would rather spend energy on fixing the issues with MUC than rewriting one of the largest components from scratch."

"MUC and MIX have almost the same set of features, just different protocols/implementations. Which means they are mostly relevant to developers. We've not rushed to implement MIX because MUC is so widely supported, and doesn't have any problems that can't be fixed without switching to something entirely different."

I wouldn't hold my breath
@lanodan