 ===== 1) File name: config/tcpdf_config.php 
 
-- Old Code ( Make Comment )
//define ('K_PATH_FONTS', K_PATH_MAIN.'fonts/');

-- New Code ( Add New code )
$fdir = realpath( WOO_VOU_DIR.'/includes/tcpdf/fonts' );
if (substr($fdir, -1) != '/') {
	$fdir .= '/';
}
define ('K_PATH_FONTS', apply_filters( 'woo_vou_tcpdf_fonts_path', $fdir ) );

===== 2) Replace complete font folder of old library when updating new library

===== 3) File name: config/tcpdf_config.php (it's for qrcode and barcode to add in PDF using writeHTML method) ( Change below constant value with true )

-- Old Code
define('K_TCPDF_CALLS_IN_HTML', false);

-- New Code
define('K_TCPDF_CALLS_IN_HTML', true);

===== 4) File name: tcpdf.php (to allow multiple instances of TCPDF object)

-- Old Code

protected function unserializeTCPDFtagParameters($data) {
    $hash = substr($data, 0, 32);
    $encoded = substr($data, 32);
    if ($hash != $this->getHashForTCPDFtagParams($encoded)) {
        $this->Error('Invalid parameters');
    }
    return json_decode(urldecode($encoded), true);
}

-- New Code ( Comment If condition )

protected function unserializeTCPDFtagParameters($data) {
    $hash = substr($data, 0, 32);
    $encoded = substr($data, 32);
    /*if ($hash != $this->getHashForTCPDFtagParams($encoded)) {
        $this->Error('Invalid parameters');
    }*/
    return json_decode(urldecode($encoded), true);
}

===== 5) File name: config/tcpdf_config.php (to modify default font variables 'PDF_FONT_NAME_MAIN' and 'PDF_FONT_NAME_DATA')

-- Old Code

/**
 * Default main font name.
 */
define ('PDF_FONT_NAME_MAIN', 'helvetica');

/**
 * Default data font name.
 */
define ('PDF_FONT_NAME_DATA', 'helvetica');

-- New Code

/**
 * Default main font name.
 */
$defaultFont = 'helvetica';
define ('PDF_FONT_NAME_MAIN', apply_filters( 'woo_vou_tcpdf_main_font', $defaultFont ));

/**
 * Default data font name.
 */
define ('PDF_FONT_NAME_DATA', apply_filters( 'woo_vou_tcpdf_data_font', $defaultFont ));


========== 6) tcpdf.php

---- OLD CODE

class TCPDF {

----- NEW CODE ( Change Default Class win new )

class WPWEB_TCPDF {

========== 7) tcpdf_autoconfig.php

---- added slug WPWEB_ before the original constant name

========== 8) tcpdf_import.php

---- OLD CODE

class TCPDF_IMPORT extends TCPDF {


---- NEW CODE ( Change Default Class with New )

class TCPDF_IMPORT extends WPWEB_TCPDF {


========== 9) include/tcpdf_font_data.php

--- OLD CODE

class TCPDF_FONT_DATA {


----- NEW CODE ( Add Exists condition )

if( !class_exists('TCPDF_FONT_DATA')) {

class TCPDF_FONT_DATA {


========== 10) include/tcpdf_font.php ( Replace constane in whole file )

---- Change class name TCPDF_FONTS to WPWEB_TCPDF_FONTS to whole file


============= 11) tcpdf.php ( Change Default Class to New )
----- Change class name TCPDF_FONTS to WPWEB_TCPDF_FONTS

============= 12) /tools/tcpdf_addfont.php
----- Change class name TCPDF_FONTS to WPWEB_TCPDF_FONTS


============= 13) includes/tcpdf_colors.php

-------- old code

class TCPDF_COLORS {

-------- New code ( Add Exists condition )

if( !class_exists('TCPDF_COLORS')) {

class TCPDF_COLORS {


============= 14) includes/tcpdf_images.php

-------- old code

class TCPDF_IMAGES {

-------- New code ( Add Exists condition )

if( !class_exists('TCPDF_IMAGES')) {

class TCPDF_IMAGES {


============= 15) includes/tcpdf_static.php

-------- old code

class TCPDF_STATIC {

-------- New code ( Add Exists condition )

if( !class_exists('TCPDF_STATIC')) {

class TCPDF_STATIC {