Are there specific changes in the template engine or character encoding that could affect the recognition and replacement of placeholders in email templates during a vTigerCRM upgrade?

During a vTigerCRM upgrade, specific changes in the template engine or character encoding could potentially affect the recognition and replacement of placeholders in email templates. To address this issue, you may need to adjust the template engine settings or ensure that the character encoding used in the email templates is compatible with the upgraded version of vTigerCRM.

// Example PHP code snippet to adjust template engine settings
$config = $adb->getOne('SELECT value FROM vtiger_portalconfig WHERE name = "template"');
if($config == 'smarty') {
    // Adjust Smarty template engine settings here
} elseif($config == 'twig') {
    // Adjust Twig template engine settings here
} else {
    // Handle other template engines accordingly
}