Online PHP editor | output for dKPrY

@ 2017-02-07T20:56:41Z

<?php

$startDateTime = new DateTime('2016-10-17');
$currentDate = new DateTime('2017-2-5');

 $startDateTime->modify('+1 day');
        $currentWeekNumber = $currentDate->format('W') + (($currentDate->format('o') - $startDateTime->format('o')) * 52);

        //Subtract the start week from the current week (and add 1, since we start at Week 1) to find the current study week
        echo $currentWeekNumber - $startDateTime->format('W') + 1;

Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.4, 8.3.6: 16
Output for 8.3.5: 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 16

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