What potential issues can arise when calculating the future calendar week in PHP?

One potential issue when calculating the future calendar week in PHP is that the week number may not be accurate if the year changes during the week. To solve this, you can use the ISO-8601 week date system which defines the first week of the year as the one that contains the first Thursday. 

$date = new DateTime();
$date->modify('+1 week');
$weekNumber = $date->format('W');
echo $weekNumber;

Keywords

date strtotime week number calendar calculation

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