DateTime::ISO8601 is not ISO-8601 compatible. Use DateTime::ATOM instead. Source: https://www.php.net/manual/en/class.datetimeinterface.php#datetime.constants.types
DateTime::ISO8601 is not ISO-8601 compatible. Use DateTime::ATOM instead.
Source: https://www.php.net/manual/en/class.datetimeinterface.php#datetime.constants.types