DST-Issues in PHPs Date-Component

expectedResult

2016-10-30T01:30:00+02:00
2016-10-30T02:30:00+02:00
2016-10-30T02:30:00+01:00
2016-10-30T03:30:00+01:00

test.php

<?php
$interval = new DateInterval('PT1H');
// DST change in Europe is on the 30. October 2016
$dateTimeStart =  new DateTimeImmutable('2016-10-30 01:30:00', new DateTimezone('Europe/Berlin'));
$dateTimeEnd   =  new DateTimeImmutable('2016-10-30 03:31:00', new DateTimezone('Europe/Berlin'));

$period = new DatePeriod($dateTimeStart, $interval, $dateTimeEnd);

foreach ($period as $date) {
    echo $date->format('c') . "\n";
}

// See the result at https://3v4l.org/2aDp3