Replacement for the CyberPower PowerPanel email notify script, which does not work on Ubuntu

pwrstatd-email.sh

#!/usr/bin/php
<?php

class EventWrapper {
        public function __construct($vars) {
                foreach ($vars as $name => $val) $this->$name = $val;
        }
        public function __get($name) {
                return property_exists($this, $name)? $this->$name: null;
        }
}

$e = new EventWrapper($_ENV);
$e->SUBJECT = "PowerPanel Notification - [$e->EVENT]";
$e->FROM = "PowerPanel Daemon <$e->SENDER_ADDRESS>";
$e->TO = "$e->RECEIPT_NAME <$e->RECEIPT_ADDRESS>";
$e->MESSAGE = "Warning: The $e->EVENT event has occurred for a while, system will be shutdown immediately!";
$e->DATE = date('r');
$e->RUNTIME = "";

if ($e->REMAINING_RUNTIME != 'none') {
        $e->RUNTIME = "Remaining Runtime: $e->REMAINING_RUNTIME Seconds";
}

$e->DATA = <<<EOL
========================================================
   $e->SUBJECT
========================================================

$e->MESSAGE
Time: $e->DATE

UPS Model Name: $e->MODEL_NAME
Battery Capacity: $e->BATTERY_CAPACITY %
$e->RUNTIME
EOL;

$headers = "From: $e->FROM\r\n";

mail($e->TO, $e->SUBJECT, $e->DATA, $headers);