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1 The stable Postfix release is called postfix-2.4.x where 2=major
2 release number, 4=minor release number, x=patchlevel. The stable
3 release never changes except for patches that address bugs or
4 emergencies. Patches change the patchlevel and the release date.
6 New features are developed in snapshot releases. These are called
7 postfix-2.5-yyyymmdd where yyyymmdd is the release date (yyyy=year,
8 mm=month, dd=day). Patches are never issued for snapshot releases;
9 instead, a new snapshot is released.
11 The mail_release_date configuration parameter (format: yyyymmdd)
12 specifies the release date of a stable release or snapshot release.
14 Major changes - critical
15 ------------------------
17 See RELEASE_NOTES-2.3 if you upgrade from Postfix 2.2 or earlier.
19 [Incompat 20070122] To take advantage of the new support for BSD
20 kqueue, Linux epoll, or Solaris /dev/poll, you must restart (not
21 reload) Postfix after upgrading from Postfix 2.3.
23 [Incompat 20061209] If you upgrade Postfix without restarting, you
24 MUST execute "postfix reload", otherwise the queue manager may log
25 a warnings with:
27 warning: connect to transport retry: Connection refused
29 [Incompat 20061209] The upgrade procedure adds a new "retry" service
30 to the master.cf file. If you make the mistake of copying old
31 Postfix configuration files over the new files, the queue manager
32 may log warnings with:
34 warning: connect to transport retry: Connection refused
36 To fix your master.cf file, use "postfix upgrade-configuration"
37 followed by "postfix reload".
39 Major changes - safety
40 ----------------------
42 [Incompat 20070222] As a safety measure, Postfix now by default
43 creates mailbox dotlock files on all systems. This prevents problems
44 with GNU POP3D which subverts kernel locking by creating a new
45 mailbox file and deleting the old one.
47 Major changes - Milter support
48 ------------------------------
50 [Feature 20070121] The support for Milter header modification
51 requests was revised. With minimal change in the on-disk representation,
52 the code was greatly simplified, and regression tests were updated
53 to ensure that old errors were not re-introduced. The queue file
54 format is entirely backwards compatible with Postfix 2.3.
56 [Feature 20070116] Support for Milter requests to replace the message
57 body. Postfix now implements all the header/body modification
58 requests that are available with Sendmail 8.13.
60 [Incompat 20070116] A new field is added to the queue file "size"
61 record that specifies the message content length. Postfix 2.3 and
62 older Postfix 2.4 snapshots will ignore this field, and will report
63 the message size as it was before the body was replaced.
65 Major changes - TLS support
66 ---------------------------
68 [Incompat 20061214] The check_smtpd_policy client sends TLS certificate
69 attributes (client ccert_subject, ccert_issuer) only after successful
70 client certificate verification. The reason is that the certification
71 verification status itself is not available in the policy request.
73 [Incompat 20061214] The check_smtpd_policy client sends TLS certificate
74 fingerprint information even when the certificate itself was not
75 verified.
77 [Incompat 20061214] The remote SMTP client TLS certificate fingerprint
78 can be used for access control even when the certificate itself was
79 not verified.
81 [Incompat 20061006] The format of SMTP server TLS session cache
82 lookup keys has changed. The lookup key now includes the master.cf
83 service name.
85 Major changes - performance
86 ---------------------------
88 [Feature 20070212] Better support for systems that run thousands
89 of Postfix processes. Postfix now supports FreeBSD kqueue(2),
90 Solaris poll(7d) and Linux epoll(4) as more scalable alternatives
91 to the traditional select(2) system call, and uses poll(2) when
92 examining a single file descriptor for readability or writability.
93 These features are supported on sufficiently recent versions of
94 FreeBSD, NetBSD, OpenBSD, Solaris and Linux; support for other
95 systems will be added as evidence becomes available that usable
96 implementations exist.
98 [Incompat 20070201] Some default settings have been adjusted to
99 better match contemporary requirements:
101 - queue_run_delay and minimal_backoff_time were reduced from 1000s
102 to 300s so that deliveries are retried earlier after the first
103 failure.
105 - ipc_idle was reduced from 100s to 5s, so that tlsmgr and scache
106 clients will more quickly release unused file handles.
108 [Feature 20061209] Improved worst-case (old and new) queue manager
109 performance when deferring or bouncing large amounts of mail. Instead
110 of talking to the bounce or defer service synchronously, this work
111 is now done in the background by the error or retry service.
113 [Feature 20061209] Improved worst-case (new) queue manager performance
114 when delivering multi-recipient mail. The queue manager now proactively
115 reads recipients from the queue file, instead of waiting for the
116 slowest deliveries to complete before reading in new recipients.
117 This introduces two parameters: default_recipient_refill_limit (how
118 many recipient slots to refill at a time) and
119 default_recipient_refill_delay (how long to wait between refill
120 operations). These two parameters act as defaults for optional
121 per-transport settings.
123 Major changes - delivery status notifications
124 ---------------------------------------------
126 [Incompat 20061209] Small changes were made to the default bounce
127 message templates, to prevent HTML-aware software from hiding or
128 removing the text "<postmaster>", and producing misleading text.
130 [Incompat 20060806] Postfix no longer announces its name in delivery
131 status notifications. Users believe that Wietse provides a free
132 help desk service that solves all their email problems.
134 Major changes - ETRN support
135 ----------------------------
137 [Feature 20061217] More precise queue flushing with the ETRN,
138 "postqueue -s site", and "sendmail -qRsite" commands, after
139 minimization of race conditions. New per-queue-file flushing with
140 "postqueue -i queueid" and "sendmail -qIqueueid".
142 Major changes - small office/home office support
143 ------------------------------------------------
145 [Incompat 20061217] Postfix no longer requires a domain name. It
146 uses "localdomain" as the default Internet domain name when no
147 domain is specified via main.cf or via the machine's hostname.
149 Major changes - SMTP access control
150 -----------------------------------
152 [Incompat 20061214] The check_smtpd_policy client sends TLS certificate
153 attributes (client ccert_subject, ccert_issuer) only after successful
154 client certificate verification. The reason is that the certification
155 verification status itself is not available in the policy request.
157 [Incompat 20061214] The check_smtpd_policy client sends TLS certificate
158 fingerprint information even when the certificate itself was not
159 verified.
161 [Incompat 20061214] The remote SMTP client TLS certificate fingerprint
162 can be used for
163 access control even when the certificate itself was not verified.
165 [Incompat 20061209] The Postfix installation procedure no longer
166 updates main.cf with "unknown_local_recipient_reject_code = 450".
167 Four years after the introduction of mandatory recipient validation,
168 this transitional tool is no longer neeed.
170 Major changes - workarounds
171 ---------------------------
173 [Incompat 20070222] As a safety measure, Postfix now by default
174 creates mailbox dotlock files on all systems. This prevents problems
175 with GNU POP3D which subverts kernel locking by creating a new
176 mailbox file and deleting the old one.
178 [Feature 20061209] Better interoperability with non-conforming SMTP
179 servers that reply and disconnect before Postfix has sent the
180 complete message content.
182 [Feature 20061209] Better support for queue file systems on file
183 servers with drifting clocks. Clock skew can be a problem, because
184 Postfix does not deliver mail until the local clock catches up with
185 the queue file's last modification time stamp. On systems with
186 usable futimes() or equivalent (Solaris, *BSD, MacOS, but not Linux),
187 Postfix now always explicitly sets the queue file last modification
188 time stamps while creating a queue file. On systems without usable
189 futimes() (Linux, and ancient versions of Solaris, SunOS and *BSD)
190 Postfix keeps using the slower utime() system call to update queue
191 file time stamps when the file system clock is off with respect to
192 the local system clock, and logs a warning.
194 [Feature 20061006] Individual CISCO PIX bug workarounds are now
195 on/off configurable. This introduces new parameters: smtp_pix_workarounds
196 (default: disable_esmtp, delay_dotcrlf) and smtp_pix_workaround_maps
197 (workarounds indexed by server IP address). The default settings
198 are backwards compatible.