It is now possible to set the super-conference of a conf to zero.

src/server/conference.c

@@ -707,7 +707,8 @@ set_super_conf (Conf_no  conf_no,
     
     CHK_LOGIN(FAILURE);
     GET_C_STAT(conf_c, conf_no, FAILURE);
-    CHK_EXIST(new_super_conf, FAILURE);
+    if (new_super_conf != 0)
+	CHK_EXIST(new_super_conf, FAILURE);
 
     if ( !is_supervisor(conf_no, conf_c)
 	&& !ENA(admin, 5) )