anchor.diff:  format_error({relup_generation_warning, Module, Warnings}) ->
       ["Warnings generating relup \s",
        rlx_util:indent(2), Module:format_warning(Warnings)];
  +format_error({no_upfrom_release_found, undefined}) ->
  +    io_lib:format("No earlier release for relup found", []);
  +format_error({no_upfrom_release_found, Vsn}) ->
  +    io_lib:format("Upfrom release version (~s) for relup not found", [Vsn]);
   format_error({relup_script_generation_error,
                 {relup_script_generation_error, systools_relup,
                  {missing_sasl, _}}}) ->
  
positive.code:         end,
      case UpFrom of
          undefined ->
              ?RLX_ERROR(no_upfrom_release_found);
          _ ->
              make_upfrom_script(State, Release, UpFrom)
      end.
  
negative.code:     end.
  
  make_relup(State, Release) ->
      Vsn = rlx_state:upfrom(State),
      UpFrom =
          case Vsn of
              undefined ->
                  get_last_release(State, Release);
              Vsn ->
  