Postfix stable release 3.10.8 and legacy releases 3.9.9, 3.8.15, 3.7.20

[An on-line version of this announcement will be available at https://www.postfix.org/announcements/postfix-3.10.8.html]

Fixes for all supported Postfix releases:

• Improved Milter error handling for messages that arrive over a long-lived SMTP connection, by changing the default milter_default_action from "tempfail" to the new "shutdown" action (i.e. disconnect the remote SMTP client).

  The problem was that after a single Milter error, Postfix could tempfail all messages that the client sends over a long-lived connection, even if the Milter error was only temporary. This problem was reported by Ankit Kulkarni.

• Bugfix (defect introduced: Postfix 2.11): "posttls-finger -v -v -v" terminated with a panic, caused by recursive logging. Reported by Geert Hendrickx, diagnosed by Viktor Dukhovni, and fixed by Wietse.

With one simple change, the patch for Postfix 3.7 should also apply to older Postfix versions, because the patch affects code that has not changed in a decade or so. The simple change is to remove the Prereq: line, and to remove the part that updates the HISTORY file.

You can find the updated Postfix source code at the mirrors listed at https://www.postfix.org/.

The Extended Stable channel has been updated to 144.0.7559.220 for Windows and Mac which will roll out over the coming days/weeks.

This release specifically addresses issues introduced in v25.12.4, where drawings could become non-editable in certain scenarios due to content filtering rules.

Links

• Update instructions

Full List of Changes

This release contains the following fixes and changes:

• Updated content filter to allow required drawio diagram attributes. (#6026)

Below are development builds for testing purposes.

Latest development build: 2.6.2.25 (March 1st 2026)

Latest stable release build: 2.6.2.1
https://github.com/clsid2/mpc-hc/releases/tag/2.6.2