<?php
$dt = new DateTime('20151215T073625Z');
// $tz = new DateTimeZone('Asia/Kolkata'); // or whatever zone you're after
// $dt->setTimezone($tz);
echo $dt->format('Y-m-d H:i:s');
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
2015-12-15 07:36:25