What are some best practices for handling special characters like umlauts in PHP when sorting data?

Special characters like umlauts can cause issues when sorting data in PHP because they are not always treated as expected due to their encoding. To handle this, you can use the `collator` class in PHP, which provides locale-specific sorting. By setting the locale to a language that uses umlauts, you can ensure that the sorting is done correctly.

$collator = new Collator('de_DE');
$collator->sort($array);