This is the Postfix 3.10 experimental release.

The stable Postfix release is called postfix-3.9.x where 3=major
release number, 9=minor release number, x=patchlevel. The stable
release never changes except for patches that address bugs or
emergencies. Patches change the patchlevel and the release date.

New features are developed in snapshot releases. These are called
postfix-3.10-yyyymmdd where yyyymmdd is the release date (yyyy=year,
mm=month, dd=day). Patches are never issued for snapshot releases;
instead, a new snapshot is released.

The mail_release_date configuration parameter (format: yyyymmdd)
specifies the release date of a stable release or snapshot release.

If you upgrade from Postfix 3.8 or earlier, please read RELEASE_NOTES-3.9
before proceeding.

Dual license
------------

As of Postfix 3.2.5 this software is distributed with a dual license:
in addition to the historical IBM Public License (IPL) 1.0, it is
now also distributed with the more recent Eclipse Public License
(EPL) 2.0. Recipients can choose to take the software under the
license of their choice. Those who are more comfortable with the
IPL can continue with that license.

[Feature 20250105]

Support for automatic RFC 2047 encoding of non-ASCII "full name"
information in Postfix-generated From: message headers. Encoding
non-ASCII full names can avoid the need to use SMTPUTF8, and therefore
can avoid incompatibility with sites that do not support SMTPUTF8.

Background: when a message without a From: header is submitted with the
Postfix sendmail(1) command, Postfix will add a From: header and will
try to use the sender's full name specified with the Postfix sendmail(1)
"-F" option, with the sendmail(1) "NAME" environment variable, or
with the GECOS field in the UNIX password database.

This introduces a new configuration parameter "full_name_encoding_charset"
(default: utf8) which specifies the character set of the full name
information in the Postfix sendmail(1) "-F" option or "NAME"
environment variable, or in the GECOS field in the UNIX password
database.

[Incompat 20250105]

The SMTP server now logs the queue ID (or "NOQUEUE") when a connection
ends abnormally (timeout, lost connection, or too many errors).

[Feature 20250105]

The SMTP server now logs the queue ID (or "NOQUEUE") when a connection
ends abnormally (timeout, lost connection, or too many errors).

[Feature 20241104]

The cleanup server now logs "queueid: canceled" when a message
transaction is started but not completed. This provides a clear
signal to logfile collation tools.

[Feature 20240926]

Support for the TLSRPT protocol (defined in RFC 8460). With this,
an email receiving domain can publish a policy in DNS, and request
daily summary reports for successful and failed SMTP-over-TLS
connections to that domain's MX hosts.

Postfix supports TLSRPT summaries for DANE (built-in) and MTA-STS
(via an smtp_tls_policy_maps plugin). For details, see TLSRPT_README.