anchor.diff:          (assertValueOneOf "EmitTimezone" boolValues)
         ];
   
  -      sectionIPv6PrefixDelegation = checkUnitConfig "IPv6PrefixDelegation" [
  +      sectionIPv6SendRA = checkUnitConfig "IPv6SendRA" [
           (assertOnlyFields [
             "Managed"
             "OtherInformation"
  
positive.code:           [DHCPServer]
            ${attrsToSection def.dhcpServerConfig}
          ''
          + optionalString (def.ipv6PrefixDelegationConfig != { }) ''
            [IPv6PrefixDelegation]
            ${attrsToSection def.ipv6PrefixDelegationConfig}
          ''
          + flip concatMapStrings def.ipv6Prefixes (x: ''
            [IPv6Prefix]
  
negative.code:       '';
      };
  
      # systemd.network.networks.*.ipv6PrefixDelegationConfig has been deprecated
      # in 247 in favor of systemd.network.networks.*.ipv6SendRAConfig.
      ipv6PrefixDelegationConfig = mkOption {
        visible = false;
        apply = _: throw "The option `systemd.network.networks.*.ipv6PrefixDelegationConfig` has been replaced by `systemd.network.networks.*.ipv6SendRAConfig`.";
      };
  
      ipv6SendRAConfig = mkOption {
        default = {};
        example = { EmitDNS = true; Managed = true; OtherInformation = true; };
        type = types.addCheck (types.attrsOf unitOption) check.network.sectionIPv6SendRA;
        description = ''
          Each attribute in this set specifies an option in the
          <literal>[IPv6SendRA]</literal> section of the unit.  See
          <citerefentry><refentrytitle>systemd.network</refentrytitle>
          <manvolnum>5</manvolnum></citerefentry> for details.
        '';
  