Convert PDF file to v1.4

convert.md

// Not much of PHP magic
// This just takes a PDF file from a path
// and executes Ghostscript to convert your
// PDF to version 1.4

// You need to have Ghostscript installed
// See https://www.ghostscript.com/Documentation.html

$PDFFile = '/path/to/your/pdf.pdf';
$newName = substr($PDFFile, 0, -4) . '_new.pdf';
$command = 'gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dNOPAUSE -dQUIET -dBATCH -sOutputFile=' . $newName . ' ' . $PDFFile;
exec($command);

Thank you. Fixed the issue.