RFC 4616 specifies the authzid is optional in the client authentication
message and that the server will derive the authorisation identity
(authzid) from the authentication identity (authcid) when not specified
by the client.
... and add "MAILINDEX".
As described in #2789, this is a suggested solution. Changing UID=xx to
actually get mail with UID xx and add "MAILINDEX" to get a mail with a
special index in the mail box (old behavior). So MAILINDEX=1 gives the
first non deleted mail in the mail box.
Fixes#2789Closes#2815
As the email protocols implement SASL authentication rather than IMAP,
POP3 and SMTP specific authentication, updated the authentication
keywords to reflect this.
