--- a/mod_muc_mav/mod_muc_mav.lua	Mon May 11 13:37:19 2026 +0100
+++ b/mod_muc_mav/mod_muc_mav.lua	Mon May 18 10:23:12 2026 -0500
@@ -7,6 +7,7 @@
 local xmlns_mav = "urn:xmpp:muc:affiliations:1";
 local xmlns_muc = "http://jabber.org/protocol/muc";
 local xmlns_muc_user = "http://jabber.org/protocol/muc#user";
+local xmlns_occupant_id = "urn:xmpp:occupant-id:0";
 
 local mav_versions = {}
 
@@ -15,8 +16,10 @@
 	local x = st.stanza("x", {xmlns = xmlns_muc_user;});
 	for jid, affiliation, affiliation_data in room:each_affiliation() do
 		table.insert(jid_affiliations, jid.."\0"..affiliation);
+		local occupant_id = room:get_occupant_id_from_jid(jid);
 		local nick = affiliation_data and affiliation_data.reserved_nickname;
-		x:tag("item", {affiliation = affiliation or "none"; jid = jid; nick = nick;}):up();
+		x:tag("item", {affiliation = affiliation or "none"; jid = jid; nick = nick;})
+			:tag("occupant-id", { xmlns = xmlns_occupant_id, id = occupant_id }):up():up();
 	end
 	table.sort(jid_affiliations);
 	local hash_input = table.concat(jid_affiliations, "\0");