anchor.diff:        default = 0;
         description = ''
           Verbosity level.
  +      '';
  +    };
  +
  +    version = mkOption {
  +      type = types.nullOr types.str;
  +      default = null;
  +      description = ''
  +        The version string replied for CH TXT version.server and version.bind
  +        queries. Will use the compiled package version on null.
  +        See hideVersion for enabling/disabling this responses.
         '';
       };
   
  
positive.code:       '';
      };
  
      nsid = mkOption {
        type = types.nullOr types.str;
        default = null;
  
negative.code:       ipv4-edns-size:      ${toString cfg.ipv4EDNSSize}
        do-ip6:              ${yesOrNo  cfg.ipv6}
        ipv6-edns-size:      ${toString cfg.ipv6EDNSSize}
        log-time-asci:       ${yesOrNo  cfg.logTimeAscii}
        ${maybeString "nsid: " cfg.nsid}
        port:                ${toString cfg.port}
        reuseport:           ${yesOrNo  cfg.reuseport}
        round-robin:         ${yesOrNo  cfg.roundRobin}
        server-count:        ${toString cfg.serverCount}
        ${if cfg.statistics == null then "" else "statistics:          ${toString cfg.statistics}"}
        tcp-count:           ${toString cfg.tcpCount}
        tcp-query-count:     ${toString cfg.tcpQueryCount}
        tcp-timeout:         ${toString cfg.tcpTimeout}
        verbosity:           ${toString cfg.verbosity}
        ${maybeString "version: " cfg.version}
        xfrd-reload-timeout: ${toString cfg.xfrdReloadTimeout}
        zonefiles-check:     ${yesOrNo  cfg.zonefilesCheck}
  
  