Wietse Venema has announced the availability of Postfix version 2.4.6, as well as versions 2.3.13 and 2.2.12. These releases are only bugfixes and do not include any new features. The new releases include the following bugfixes:

• When a remote SMTP client TLS certificate had an unparsable canonical name, the Postfix SMTP server would panic due to an attempt to allocate zero-length memory.
• On backup MX servers where the queue file system was mounted with 'atime' updates disabled, the flush daemon would trigger mail delivery attempts every 1000 seconds, ignoring the maximal_backoff_time setting.

In addition, Postfix 2.2.12 includes a fix backported from Postfix 2.3. The Postfix SMTP client could get out of sync with the remote SMTP server when SMTP server tarpit delays were larger than smtp_rset_timeout.

Wietse has also promised that a stress-adaptive behavior feature currently available in the experimental Postfix 2.5 release will be made available in the future. This patch should make Postfix more responsive when all SMTP server ports are busy.

Postfix source code can be downloaded from one of the Postfix source mirrors.