How do conflicting encoding declarations in PHP files affect the display of special characters like Umlauts?

Conflicting encoding declarations in PHP files can lead to issues with displaying special characters like Umlauts. To solve this problem, ensure that all PHP files have consistent encoding declarations, such as UTF-8, at the beginning of the file. This will help PHP interpret and display special characters correctly.

<?php
header('Content-Type: text/html; charset=utf-8');
?>