anchor.diff:            end, McdConfig),
   
       [{set, McdKey, NewOrUpdatedParams ++ StrippedMcdConfig}].
  +
  +upgrade_config_from_3_0_to_3_0_1(Config) ->
  +    ?log_info("Upgrading config from 3.0 to 3.0.1"),
  +    DefaultConfig = default(),
  +    do_upgrade_config_from_3_0_to_3_0_1(Config, DefaultConfig).
  +
  +do_upgrade_config_from_3_0_to_3_0_1(Config, DefaultConfig) ->
  +    McdKey = {node, node(), memcached},
  +    {value, DefaultMcdConfig} = ns_config:search([DefaultConfig], McdKey),
  +    {value, CurrentMcdConfig} = ns_config:search(Config, McdKey),
  +    EnginesTuple = {engines, _} = lists:keyfind(engines, 1, DefaultMcdConfig),
  +    NewMcdConfig = lists:keystore(engines, 1, CurrentMcdConfig, EnginesTuple),
  +    [{set, McdKey, NewMcdConfig}].
   
   search_sub_key(Config, Key, Subkey) ->
       case ns_config:search(Config, Key) of
  
positive.code:              upgrade_config_from_2_2_0_to_2_3_0(Config)];
          {value, {2,3,0}} ->
              [{set, {node, node(), config_version}, {3,0}} |
               upgrade_config_from_2_3_0_to_3_0(Config)]
      end.
  
  upgrade_config_from_1_7_to_1_7_1() ->
  
negative.code: -define(NS_LOG, "ns_log").
  
  get_current_version() ->
      {3,0,1}.
  
  % Allow all keys to be mergable.
  
  