Fatal error: Uncaught Error: Class 'PhpOffice\PhpSpreadsheet\Writer\Xls\BIFFwriter' not found in C:\xampp7\htdocs\edgpens\extension\PhpSpreadsheet-master\src\PhpSpreadsheet\Writer\Xls\Worksheet.php:55 Stack trace: #0 {main} thrown in C:\xampp7\htdocs\edgpens\extension\PhpSpreadsheet-master\src\PhpSpreadsheet\Writer\Xls\Worksheet.php on line 55