- var_dump: documentation ( source)
<?php
var_dump(DateTime::createFromFormat('c', '2015-08-31T00:55:00Z'));
var_dump(DateTime::createFromFormat(DateTime::ISO8601, '2015-08-31T00:55:00Z'));
var_dump(DateTime::createFromFormat(DateTime::ISO8601, '2015-08-31T00:55:00.000Z'));