- date_default_timezone_set: documentation ( source)
- date: documentation ( source)
<?php
date_default_timezone_set('Asia/Singapore');
$end_date = new DateTime('today');
$end_date->modify('first day of next month');
$sumend_timestamp = $end_date->getTimestamp();
echo date('Y-m-d H:i:s', $sumend_timestamp);