Message archival and hashing MTA options

The MTA options discussed in this section relate to the envelope "journal" format captured messages that the MTA can optionally generate, as well as to the message hashes optionally generated by the MTA in order to facilitate integration with alternative message archiving software -- with regards to which, see also the Message Store archive options and Archiving messages. The   MTA option would be used when "journal" style message capture is in use (due to Sieve "  actions, or due to LDAP attribute based message capture with optional "journal" format configured). The message hashing options would be used in conjunction  with the  message hash channel options.

See also:
 * deletemessagehash Option
 * generatemessagehash Option
 * keepmessagehash Option
 * journal_format MTA Option
 * message_hash_algorithm MTA Option
 * message_hash_fields MTA Option
 * unique_id_template MTA Option
 * MTA options
 * Archiving messages
 * Message Store archive options