1--TEST-- 2Bug #80913 (DateTime(Immutable)::sub around DST yield incorrect time) 3--FILE-- 4<?php 5$date = new DateTime('2021-03-28 03:00:00', new DateTimeZone('Europe/Amsterdam')); 6$_30mbefore = (clone $date)->sub(new DateInterval('PT30M')); 7$_30mafter = (clone $date)->add(new DateInterval('PT30M')); 8 9var_dump($date->format(DATE_ATOM)); 10var_dump($_30mbefore->format(DATE_ATOM)); 11var_dump($_30mafter->format(DATE_ATOM)); 12?> 13--EXPECT-- 14string(25) "2021-03-28T03:00:00+02:00" 15string(25) "2021-03-28T01:30:00+01:00" 16string(25) "2021-03-28T03:30:00+02:00" 17