Groupchat 1.0 was probably the protocol that predated XEP-0045: Multi-User Chat and there is still some compatibility that lives on, in the XEP and in implementations.
This module tries to detect clients still using the GC 1.0 protocol and what software they run, to determine if support can be removed.
Since joins in the GC 1.0 protocol are highly ambiguous, some hits reported will be because of desynchronized MUC clients
Should work with Prosody 0.10.x and earlier.
It will not work with current trunk, since the MUC code has had major changes.
With the plugin installer in Prosody 0.12 you can use:
sudo prosodyctl install --server=https://modules.prosody.im/rocks/ mod_muc_gc10
For earlier versions see the documentation for installing 3rd party modules