anchor.diff:      DefaultConfig = default(),
       do_upgrade_config_from_3_0_2_to_3_1_5(Config, DefaultConfig).
   
  -do_upgrade_config_from_3_0_2_to_3_1_5(_Config, DefaultConfig) ->
  +do_upgrade_config_from_3_0_2_to_3_1_5(Config, DefaultConfig) ->
       MCDefaultsK = {node, node(), memcached_defaults},
       {value, NewMCDefaults} = ns_config:search([DefaultConfig], MCDefaultsK),
  -    [{set, MCDefaultsK, NewMCDefaults}].
  +
  +    JTKey = {node, node(), memcached_config},
  +    {value, {DefaultJsonTemplateConfig}} = ns_config:search([DefaultConfig], JTKey),
  +    DedupMaps = {dedupe_nmvb_maps, _} =
  +        lists:keyfind(dedupe_nmvb_maps, 1, DefaultJsonTemplateConfig),
  +    {value, {CurrentJsonTemplateConfig}} = ns_config:search(Config, JTKey),
  +    NewJsonTemplateConfig =
  +        lists:keystore(dedupe_nmvb_maps, 1, CurrentJsonTemplateConfig, DedupMaps),
  +
  +    [{set, MCDefaultsK, NewMCDefaults},
  +     {set, JTKey, {NewJsonTemplateConfig}}].
   
   search_sub_key(Config, Key, Subkey) ->
       case ns_config:search(Config, Key) of
  
positive.code:                {{node, node(), memcached},
                  [{audit_file, audit_file_path}]},
                 {{node, node(), memcached_config},
                  {[{some_other_key, some_value}]}}],
      ?assertMatch([{set, {node, _, memcached_defaults}, [{some, stuff}]}],
                   do_upgrade_config_from_3_0_2_to_3_1_5(Cfg, Default)).
  
  
  
negative.code:      {remote_clusters, []},
       {{node, node(), isasl}, [{path, filename:join(DataDir, ?ISASL_PW)}]},
  
       {{node, node(), memcached_defaults},
        [{dedupe_nmvb_maps, false}]},
  
       %% Memcached config
       {{node, node(), memcached},
  