Release Notes: This release contains a fix for CVE-2011-0411, which allows plain text command injection with SMTP sessions over TLS. This defect was introduced with Postfix version 2.2. The same flaw exists in other implementations of the STARTTLS command.
Release Notes: Postfix no longer automatically appends the system default CA certificates. When pipe-to-command delivery fails with a signal, mail is now correctly deferred, instead of being returned to sender. Poor `smtpd_proxy_filter` TCP performance over loopback (127.0.0.1) connections was fixed by adapting the output buffer size to the MTU. The SMTP server no longer applies the `reject_rhsbl_helo` feature to non-domain forms such as network addresses. The Postfix SMTP server failed to deliver a "421" response and hang up the connection after Milter error.
Release Notes: This version fixes problems such as a milter application hang, a core dump related to malformed error messages in LDAP, MySQL, or PostgreSQL lookup table configurations, a stuck-in-queue problem for mail with zero recipients, invalid host rejections for hostnames such as 1-2-3-4, and a problem with the VRFY command.
Release Notes: Reduced TCP performance is avoided when reusing an SMTP connection with a larger than 4096-byte TCP MSS value.
Release Notes: This version provides back-ported fixes that have already appeared in Postfix versions 2.5 and 2.6.
Release Notes: This release fixes minor problems in the SMTP client, and works around "noatime" mail queues.
Release Notes: This stable release fixes a one-bit typing error that slipped in during code cleanup for the Postfix 2.4.4 release, making the loopback TCP performance workaround ineffective.
Release Notes: This release fixes multiple problems with Milter support, and provides workarounds for SASL interoperability and loopback TCP performance problems.
Release Notes: An issue with 2.4.2 not compiling correctly on all platforms was corrected.
Release Notes: Solaris compatibility has been improved. A segfault with the HOLD action on 64-bit platforms has been fixed. The "postfix stop" command has been improved on Linux platforms.