Please note that Daylight Saving Time (DST) transitions only work as expected when using new \DateInterval(), not \DateInterval::createFromDateString().<?php$now = new \DateTimeImmutable("2025-03-29 13:00:00", new DateTimeZone('Europe/Berlin'));var_dump($now);// 2025-03-29 13:00:00var_dump($now->add(\DateInterval::createFromDateString('1440 minutes')));// 2025-03-30 13:00:00var_dump($now->add(new \DateInterval('PT1440M')));// 2025-03-30 14:00:00// these are not equivalent:var_dump(\DateInterval::createFromDateString('1440 minutes'));var_dump(new \DateInterval('PT1440M'));?>