anchor.diff:  get_string_config(Config, ValueName) ->
     case config_utils:get_string(Config, ValueName) of
       {ok, Value} ->
  -      case length(Value) > 0 of
  +      case string:len(Value) > 0 of
           true ->  {ok, Value};
           false -> {error, empty} % Call it an error so we don't try an set an empty option value
         end;
  
positive.code:       {proto_ver, {4}},
        {username, {""}},
        {password, {""}},
        {logger, {none}}, % logging level, for debug purposes 
                           % valid values: all, debug, info, warning, error, critical, none
        {num_of_pubs, {1}},
        {pub_topics, [{""}]},
  
negative.code: % Use the Chain pattern to build list of options for MQTT client
  %
  build_opts([], {_Config, Options}) ->
    log_server:debug("MQTT client options: ~p", [Options]),
    Options;
  
  build_opts([Fun | Funs], {Config, Options}) ->
  