Sieve setpriority and setmtpriority extensions

As of MS 7.0u4, the private " " action is available for system-level Sieves, to set an   effective message processing priority. This nonstandard extension is available without any special capability declaration; no " " action is needed for its use. " " takes a single string or integer argument which must be one of " ", " ", or " ", or an integer in the range  to  ;  (note that non-urgent corresponds to , normal to  , and urgent to  ). Note that this priority is not stored in the message header and only affects processing at this  particular stage of message transfer. If multiple " " actions       are specified in different system-level Sieves, the one in the  most specific Sieve wins.

New in MS 8.0, the " " action is available for system-level Sieves. This nonstandard extension is available without any special capability declaration; no " " action is needed for its use. " " accepts a single integer or string argument and sets the current          MT-PRIORITY to the argument value. This action is only allowed in          system-level Sieves and the argument must be in the    to   range           of valid MT-PRIORITY values.

See also:
 * Job Controller priority-based processing
 * Sieve hierarchy
 * Sieve supported extensions
 * Sieve filters