which drastically improves mail delivery performance when
VERP is being used.
In order to exploit the performance gain, one has to choose
'POSTFIX' in the OPTIONS menu, configure postfix with proper
smtpd_authorized_verp_clients settings, then add:
VERP_STYLE = 'Postfix'
to the mm_cfg.py configuration.
The Postfix style XVERP delivery is disabled by default.
PR: ports/116847
Approved by: maintainer timeout
