Default value of the $flag argument changed in PHP 8.1 from ENT_COMPAT to ENT_QUOTES | ENT_SUBSTITUTE
To ensure consistent behavior across different PHP version the second parameter is now required for the functions:
htmlspecialchars(), htmlentities(), htmlspecialchars_decode(), html_entity_decode() and get_html_translation_table()
Without this, people can craft URLs that other users might use not realising
what they do - and as a XSS vulnerability, it could do any number of things the
clicking-user has access to do on the site.
Change-Id: I82adc71e8706d8929011b4b24523d5b62b8ccea1
Marina Glancy