Auto-reply detection in PHP (with Zend)

zend_autoreply_detection.php

<?php
/**
 * See if it's an autoreply 
 * $message is of type Zend_Mail_Message
 */
$autoreply = false;
try {
  if ($message->{'X-Autoreply'}) {
    $autoreply = true;
  }
} catch (Exception $e) {}