From: Wietse Venema on
Postfix 2.7 is being readied for final release. You can find release
candidate 2 on the download sites (release candidate 1 was released
a week ago).

Postfix 2.7 brings performance improvements for before-queue content
filtering, automatic cache cleanup for the verify daemon, and
support for reputation management based on the outgoing source IP

The postscreen daemon is still to rough for a stable release and
will be made "mature" in the Postfix 2.8 development cycle.