What are the potential pitfalls of using HTML-Specialchars in PHP for XML parsing?

When using htmlspecialchars in PHP for XML parsing, the encoded characters may not be suitable for XML content. This can lead to invalid XML output or parsing errors. To solve this issue, it is recommended to use the htmlspecialchars function with the ENT_XML1 flag, which encodes characters specifically for XML content.

// Use htmlspecialchars with ENT_XML1 flag for XML parsing
$encoded_content = htmlspecialchars($content, ENT_XML1);