I’ve finaly gotten around to update and test my own installations of Postfix 2.4.0. It all works as promised and nothing has to be changed to get it working. Just follow the install instructions with the nex source and you’ll be up and running in no time. Here is a list of the major changes been made to this version:

  • Postfix can now manage thousands of connections without needing
    special main.cf, master.cf, or compile-time tweaks, on systems with BSD kqueue, Solaris /dev/poll, or Linux epoll support.
  • Milter support for message body replacement. The resulting queue
    files are backwards compatible with Postfix 2.3. The existing Milter
    support for message header manipulations was revised and is now
    implemented by much simpler code.
  • Minor improvements in TLS session cache management and in the
    implementation of certificate fingerprint based authentication. A
    more extensive revision of TLS internals will appear first in Postfix
    2.5 snapshots.
  • Improvements in queue manager performance when deferring large
    amounts of mail, or when delivering mail with lots of recipients.
  • Workarounds for SMTP servers that reply and hang up prematurely,
    for file system clocks that are out of sync, and for broken kernel
    lock management in POP servers.

One that is very good is that you no longer need to enter a valid domain name for myhostname in main.cf. Which confused many people and was difficult to use for people.