(PHP 4 >= 4.0.7, PHP 5, PHP 7) Sets the ACL for a given mailbox

(PECL mailparse >= 0.9.0) Parse RFC 822 compliant addresses

(PHP 4 >= 4.0.5, PHP 5, PHP 7) Sets a quota for a given mailbox

(PHP 4 >= 4.0.5, PECL vpopmail >= 0.2) Attempt to validate a username/domain/password

(PHP 4, PHP 5, PHP 7) Alias of

(PHP 4 >= 4.0.5, PECL vpopmail >= 0.2) Change a virtual user's password

(PHP 4 >= 4.0.5, PECL vpopmail >= 0.2) Delete a virtual domain

(PHP 4 >= 4.1.0, PECL cyrus 1.0) Authenticate against a Cyrus IMAP server

(PHP 4, PHP 5, PHP 7) Send mail bool mail ( string

(PECL mailparse >= 0.9.0) Gets the best way of encoding