[An on-line version of this announcement will be available at http://www.postfix.org/announcements/postfix-3.0.0.html]
Postfix stable release 3.0.0 is available. This release ends support for Postfix 2.8.
The main changes in no particular order are:
SMTPUTF8 support for internationalized domain names and address localparts as defined in RFC 6530 and related documents. The implementation is based on code contributed by Arnt Gulbrandsen and sponsored by CNNIC. SMTPUTF8 support is a work in progress; it is expected to be completed during the Postfix 3.1 development cycle. See SMTPUTF8_README for a summary of limitations.
Support for Postfix dynamically-linked libraries and database plugins. The implementation is based on code by LaMont Jones for Debian Linux. See INSTALL for detailed descriptions of the available options.
An OPT-IN safety net for the selective adoption of new Postfix default settings. If you do nothing, the old Postfix default settings *should* remain in effect (complain to your downstream maintainer if that is not the case). See COMPATIBILITY_README for detailed descriptions of Postfix logfile messages.
Support for operations on multiple lookup tables. The pipemap:{map1,map2...} database type implements a pipeline of lookup tables where the result from one lookup table becomes a query for the next table; the unionmap:{map1,map2,...} database type sends the same query to multiple lookup tables and concatenates their results.
Support for pseudo-tables that make simple things easy to implement. The inline:{key1=value1,key2=value2,...} table avoids the need to create an external file for just a few items; and the randmap{value1,value2,...} table implements random selection from the specified values.
Table-driven transformation of DNS lookup results and of delivery agent status codes and messages. Typically, one would use a PCRE table to fix problematic DNS responses or to fix the handling of delivery errors. See smtp_dns_reply_filter, smtp_delivery_status_filter, and similarly-named parameters for other Postfix daemons.
Improved configuration file syntax with support for the ternary operator such as ${name?{iftrue}:{iffalse}}, comparison operators such as ${{expr1}==${expr2}?{iftrue}:{iffalse}}, per-Milter and per-policy server timeout and other settings, master.cf parameters that contain whitespace, import/export_environment settings that contain whitespace, and "static" table lookup results that contain whitespace. Support for multiple lookup results in access(5) and header/body_checks(5) tables is expected to be completed in the Postfix 3.1 development cycle.
Per-session command profiles, logged at the end of each inbound SMTP session. For example, a password-guessing bot is logged as "disconnect from name[addr] ehlo=1 auth=0/1 commands=1/2", meaning that the client sent one EHLO command that worked, one AUTH command that failed, and hung up without sending a QUIT command. This information is always logged, and can help to solve puzzles without verbose logging or network sniffers.
You can find the Postfix source code at the mirrors listed at http://www.postfix.org/.