anchor.diff:          '';
         };
   
  +      extraConfig = mkOption {
  +        type = types.lines;
  +        default = "";
  +        description = ''
  +          Additional configuration to be copied verbatim into <filename>zabbix.conf.php</filename>.
  +        '';
  +      };
  +
       };
     };
   
     # implementation
   
     config = mkIf cfg.enable {
  +
  +    services.zabbixWeb.extraConfig = optionalString ((versionAtLeast config.system.stateVersion "20.09") && (versionAtLeast cfg.package.version "5.0.0")) ''
  +      $DB['DOUBLE_IEEE754'] = 'true';
  +    '';
   
       systemd.tmpfiles.rules = [
         "d '${stateDir}' 0750 ${user} ${group} - -"
  
positive.code: let
  
    inherit (lib) mkDefault mkEnableOption mkForce mkIf mkMerge mkOption types;
    inherit (lib) literalExample mapAttrs optionalString;
  
    cfg = config.services.zabbixWeb;
    fpm = config.services.phpfpm.pools.zabbix;
  
negative.code:     $ZBX_SERVER_PORT = '${toString cfg.server.port}';
      $ZBX_SERVER_NAME = ''';
      $IMAGE_FORMAT_DEFAULT = IMAGE_FORMAT_PNG;
  
      ${cfg.extraConfig}
    '';
  
  in
  