Contao\Database\Updater::run33Update PHP Method

    public function run33Update()
    {
        $objLayout = $this->Database->query("SELECT id, framework FROM tl_layout WHERE framework!=''");
        while ($objLayout->next()) {
            $strFramework = '';
            $tmp = \StringUtil::deserialize($objLayout->framework);
            if (!empty($tmp) && is_array($tmp)) {
                if (($key = array_search('layout.css', $tmp)) !== false) {
                    array_insert($tmp, $key + 1, 'responsive.css');
                }
                $strFramework = serialize(array_values(array_unique($tmp)));
            }
            $this->Database->prepare("UPDATE tl_layout SET framework=? WHERE id=?")->execute($strFramework, $objLayout->id);
        }
        // Add the "viewport" field (triggers the version 3.3 update)
        $this->Database->query("ALTER TABLE `tl_layout` ADD `viewport` varchar(64) NOT NULL default ''");
    }