This module implements XEP-0463, specifically version 0.2 of it. It does so without any additional storage requirements and everything needed is handled in-memory only.
This module does not preserve a version history, it only knows about the state before and after a change and the current set of affiliations. This means that if affiliations are changed while a user device is offline, they will receive a full response when reconnecting with the room. This is in line with the behavior the XEP describes for the case of the client sending a version unknown to the server.
Tested only on Prosody 13.
With the plugin installer in Prosody 0.12 you can use:
sudo prosodyctl install --server=https://modules.prosody.im/rocks/ mod_muc_mavFor earlier versions see the documentation for installing 3rd party modules