diff -r d69521003e91 -r 7a37fade5380 plugins/muc/muc.lib.lua
--- a/plugins/muc/muc.lib.lua	Fri Apr 15 18:03:55 2016 +0200
+++ b/plugins/muc/muc.lib.lua	Sun Apr 17 22:09:44 2016 +0200
@@ -1235,6 +1235,14 @@
 	}, room_mt);
 end
 
+function room_mt:freeze()
+	return {
+		jid = self.jid;
+		_data = self._data;
+		_affiliations = self._affiliations;
+	}
+end
+
 _M.room_mt = room_mt;
 
 return _M;