Defer header addition MTA option

Sieve filter interpretation MTA options:  (0 or 1)
The  MTA option controls whether Sieve filters see headers added to messages prior to Sieve processing. This includes, but is not limited to, headers added by list expansion processing. In older versions, such added headers would not be visible to Sieve filters. This option was added for Messaging Server 7.0u5p31 with a default of ,  meaning that added headers are seen by Sieve filters; setting the option  to   restores the older behavior (where such added headers are not visible to Sieve filters on redirected messages).

Prior to the 8.0 release, Sieve " "  used deferred reprocessing and thus any headers added to a redirected message were affected by this option. As of 8.0 Sieve " " queues to the process channel and this option no longer has any effect on header visibility in redirected messages.

See also:
 * Sieve redirect action
 * Process and reprocess channels
 * Sieve editheader extension
 * Sieve filter interpretation MTA options
 * MTA options