";
if (strpos($message_body, 'HELP') !== false) {
echo "Send STATUS {id} to get order status. Send HELP for more info.";
} else if (strpos($message_body, 'STATUS') !== false) {
// Actual order status calculation is requred.
$order_status = "pending delivery";
echo "Your order status is {$order_status}";
} else {
// You could say unsuported keyword here. We're going to just repeat HELP.
echo "Send STATUS {id} to get order status. Send HELP for more info.";
}
// Close main InboundXML tag
echo "";