Chyba mysql.php v OpenCart

Dobrý den,

Na stránce e-shopu Opencart mi to hází tuto chybu: Deprecated: mysql_connect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead in /data/web/virtuals/46057/virtual/www/domains/eshop.design-branny.com/system/database/mysql.php on line 6

Ve začátek FTP vypadá takto:

<?php
final class MySQL {
private $link;

public function __construct($hostname, $username, $password, $database) {
if (!$this->link = mysql_connect($hostname, $username, $password)) {
trigger_error(‚Error: Could not make a database link using ‚ . $username . ‚@‘ . $hostname);
}

if (!mysql_select_db($database, $this->link)) {
trigger_error(‚Error: Could not connect to database ‚ . $database);
}

mysql_query(„SET NAMES ‚utf8′“, $this->link);
mysql_query(„SET CHARACTER SET utf8“, $this->link);
mysql_query(„SET CHARACTER_SET_CONNECTION=utf8“, $this->link);
mysql_query(„SET SQL_MODE = ““, $this->link);
}

public function query($sql) {
if ($this->link) {
$resource = mysql_query($sql, $this->link);

if ($resource) {
if (is_resource($resource)) {
$i = 0;

Mohl by jste mi prosím někdo poradit, jak problém vyřešit? Co ve FTP upravit? Děkuji moc.