anchor.diff:  
   upgrade_config_explicitly(Upgrader) ->
       gen_server:call(?MODULE, {upgrade_config_explicitly, Upgrader}).
  +
  +config_version_token() ->
  +    {ets:lookup(ns_config_announces_counter, changes_counter), erlang:whereis(?MODULE)}.
   
   fold(_Fun, Acc, undefined) ->
       Acc;
  
positive.code:                               fun (Msg) ->
                                        Self ! Msg, ok
                                end),
      ns_config:cas_config(new, old),
      receive
          {cas_config, new, old} ->
  
negative.code:          proplist_get_value/3,
           merge_kv_pairs/2,
           sync_announcements/0, get_kv_list/0, get_kv_list/1,
           upgrade_config_explicitly/1, config_version_token/0,
           fold/3]).
  
  -export([save_config_sync/1]).
  