<?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);
Warning: DateTime::modify(): Failed to parse time string (first day of next month) at position 10 (o): The timezone could not be found in the database in /in/0M220 on line 5
Fatal error: Call to undefined method DateTime::getTimestamp() in /in/0M220 on line 6
Process exited with code 255.
Output for 5.2.0 - 5.2.12
Fatal error: Call to undefined method DateTime::getTimestamp() in /in/0M220 on line 6
Process exited with code 255.
Output for 5.1.0 - 5.1.6
Fatal error: Class 'DateTime' not found in /in/0M220 on line 4
Process exited with code 255.
Output for 5.0.0 - 5.0.5
Fatal error: Call to undefined function date_default_timezone_set() in /in/0M220 on line 2
Process exited with code 255.
Output for 4.4.5 - 4.4.9
Fatal error: Call to undefined function: date_default_timezone_set() in /in/0M220 on line 2
Process exited with code 255.
Output for 4.3.2 - 4.3.11, 4.4.0 - 4.4.4
Fatal error: Call to undefined function: date_default_timezone_set() in /in/0M220 on line 2
Process exited with code 255.
Output for 4.3.0 - 4.3.1
Fatal error: Call to undefined function: date_default_timezone_set() in /in/0M220 on line 2