Fatal error: Uncaught Error: Class "PhpOffice\PhpSpreadsheet\Writer\Xls\BIFFwriter" not found in /export/vol2/httpd/htdocs/administration/facilities/webapps/fluidsecure-billing/PHPSpreadsheet/Writer/Xls/Worksheet.php:57
Stack trace:
#0 {main}
  thrown in /export/vol2/httpd/htdocs/administration/facilities/webapps/fluidsecure-billing/PHPSpreadsheet/Writer/Xls/Worksheet.php on line 57