Log mtpriority MTA option

Logging message transfer priorities: (bitmask)
New in 8.0. The Message Transfer Priority SMTP extension MT-PRIORITY, defined in RFC 6710, provides the means to associate a message transfer priority with a given message. Logging of these priority values, ranging from -9 to 9, with a default value of 0, is controlled by the  MTA option.

Note that there is a Priority: header-based priority mechanism and associated logging option. These are separate mechanisms. An explicit MT-PRIORITY overrides the older Priority: header handling.

The  option defaults to 0. Setting bit 0 (value 1) enables logging of the message transfer priority associated with each transaction. The message transfer priority appears immediately after the message sensitivity and before the header-based priority in each log entry. A " " element is used in the new XML log format. If bit 1 (value 2) is set in the  MTA option, then the message transfer priority appears in the    mapping table probe, again immediately after the sensitivity field and before the header-based priority field.

See also:
 * mtprioritiesallowed Option
 * mtprioritiesrequired Option
 * mtpriority_policy MTA Option
 * Transaction logging MTA options
 * MTA transaction logging
 * log_format MTA Option
 * Triggering effects from transaction logging with LOG_ACTION
 * log_priority MTA Option
 * log_sensitivity MTA Option