Fatal error: Uncaught Error: Class 'PhpOffice\PhpSpreadsheet\Writer\Xls\BIFFwriter' not found in /home/edmedu/www/edmeducation.co.kr/tw-dev/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xls/Workbook.php:48 Stack trace: #0 {main} thrown in /home/edmedu/www/edmeducation.co.kr/tw-dev/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xls/Workbook.php on line 48