$file = 'C:\WebSiteDirectory\CarparkWeixinBackend\Dplus.apk';

        if (file_exists($file)) {

             header('Content-Description: File Transfer');

             header('Content-Type: application/vnd.android.package-archive');

             header('Content-Disposition: attachment; filename='.basename($file));

             header('Content-Transfer-Encoding: binary');

             header('Expires: 0');

             header('Cache-Control: must-revalidate, post-check=0, pre-check=0');

             header('Pragma: public');

             header('Content-Length: ' . filesize($file));

             ob_clean();

             flush();

             readfile($file);

             exit;

         }