--- a/plugins/muc/muc.lib.lua	Sat Apr 28 16:41:35 2012 +0100
+++ b/plugins/muc/muc.lib.lua	Sat Apr 28 18:36:03 2012 +0100
@@ -336,7 +336,7 @@
 	return self._data.changesubject;
 end
 function room_mt:get_historylength()
-	return self._data.history_length
+	return self._data.history_length or default_history_length;
 end
 function room_mt:set_historylength(length)
 	if tonumber(length) == nil then