What are potential solutions for handling special characters like umlauts when using PHP functions like imap_reopen?

Special characters like umlauts can be properly handled in PHP functions like imap_reopen by using the mbstring extension to ensure proper encoding. By converting the string to UTF-8 encoding before passing it to the imap_reopen function, you can avoid issues with special characters.

// Convert the string to UTF-8 encoding
$utf8_subject = mb_convert_encoding($subject, 'UTF-8', 'auto');

// Use the UTF-8 encoded string in imap_reopen function
imap_reopen($imap_stream, $mailbox . $utf8_subject);