Example 01:
<?php
date_default_timezone_set("UTC");
$dftz011 = date_default_timezone_get();
echo '<br><b>' . $dftz011 . '</b><br><br>';
$dtms011 = new DateTime();
$dtms011->setTimestamp(1234567890);
echo $dtms011->format('B => (U) => T Y-M-d H:i:s');
?>
Example 02:
<?php
date_default_timezone_set("America/New_York");
$dftz021 = date_default_timezone_get();
echo '<br><b>' . $dftz021 . '</b><br><br>';
$dtms021 = date_create();
date_timestamp_set($dtms021, 1234567890);
echo date_format($dtms021, 'B => (U) => T Y-M-d H:i:s');
?>