Postfix was released under the IBM Public License. All Postfix source code is signed with Wietse's PGP key.
Stable releases do not change except for bugfixes and for portability fixes. New features are tested out in experimental releases (see below).
Postfix 2.4 Patchlevel 0 Source code | PGP signature | Release notes | Change log
Stable releases are called "Postfix a.b.c", where a is the major release number, b is the minor release number, and c is the patchlevel.
Release candidates are made available so that people can adopt fixes before a new Postfix stable release comes out. The code may still change as new defects are discovered.
Postfix 2.4.1 stable release candidate Patch 01-RC1 | Source code | PGP signature | Release notes | Change log
New features are tested in experimental releases. They become part of the next official release once the code has not changed for a significant amount of time. Although this code is still subject to change, it runs on all of Wietse's systems so it is production quality.
Postfix 2.5 Snapshot 20070402 Source code | PGP signature | Release notes | Change log
Experimental releases are called "Postfix a.b-yyyymmdd", where a.b is the next official Postfix release and yyyymmdd is the release date.
Postfix 2.3 Patchlevel 8 Source code | PGP signature
Patch
08
07
06
05
04
03
02
01
Postfix 2.2 Patchlevel 11 Source code | PGP signature
Patch
11
10
09
08
07
06
05
04
03
02
01
Postfix 2.1 Patchlevel 06 Source code | PGP signature
Patch
06
05
04
03
02
01
Postfix 2.0 Patchlevel 20 Source code | PGP signature
Patch
20
19
18
17
16
15
14
13
12
11
10
09
08
07
06
05
04
03
02
01
Patch to black-list domain names by their mail servers (such as Verisign's mail sink) or by their DNS servers (second revision: don't defer mail when DNS lookup fails; lookup grandparent NS records).
Postfix 1.1 Patchlevel 13 Source code | PGP signature
Patch
13
12
11
10
09
08
07
06
05
04
03
02
01
Postfix 1.0 Patchlevel 08 Source code | PGP signature
(released as version 20010228)
Patch
08
07
06
05
04
03
02
01
Version 19991231 Patchlevel 13 Source code | PGP signature
Patch
13
12
11
10
09
08
07
06
05
04
03
02
01
Version 19990906 Patchlevel 09 Source code | PGP signature
Patch
09
08
07
06
05
04
03
02
01