Capability imap4 Option

Enable the IMAP4 capability. The default is normally 0 (false), but the default is 1 (true) if   (in legacy configuration,  ) is set. Compare with , which enables the modern IMAP protocol. (For the definition of IMAP4, see RFC 1730 (INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4). The more modern version of IMAP is IMAPv4rev1, initially defined in RFC 2060 (INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1), since updated by RFC 3501 (INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1).)

See also:
 * obsoleteimap Option
 * capability_imap4rev1 Option
 * IMAP options