Software supporting Mail-Followup-To

This table shows which software supports MFT and MRT:

Software	respect		view^[3]	set manually^[4]	set automatically^[5]
Software	MFT^[1]	MRT^[2]	view^[3]	set manually^[4]	MFT	MRT
Claws Mail	patch	patch	yes	yes	no	no
Evolution	no	no	yes	no	no	no
Gnus	yes	yes	yes	yes	yes	?
KMail	buggy	no	no	no	no	no
Mutt	yes	yes	yes	yes	yes	?
Opera Mail	no	no	yes	no	no	no
qmail	n/a	n/a	n/a	n/a	yes 1.02	no
Roundcube	yes 0.5	yes 0.5	yes 0.5	MFT only	no	no
Seamonkey	yes 2.0	yes	yes^[6]	yes^[6]	yes^[6] 2.0	yes^[6] 2.0
SquirrelMail	yes 1.4.5	no	plugin	no	no	no
The Bat!	?	?	yes	yes	no	no
Thunderbird	yes 1.5 / 3.0	yes 1.5	yes^[6]	yes^[6]	yes^[6] 3.0	yes^[6] 3.0

Version numbers show the first version that supported the particular feature.

Other MUAs I might add to the table: Apple Mail, IMP/Horde, Lotus Notes, Mulberry, Outlook, Outlook Express, Pegasus Mail, Pine/Alpine.

Please contact me if you have updates to this information.

^[1] When you reply-to-all to a message that has MFT set, your MUA will use it or can be configured to use it.

^[2] When you reply-to-author to a message that has MRT set, your MUA will use it or can be configured to use it.

^[3] Your MUA shows or can be configured to show MFT/MRT when viewing messages. This is not absolutely required, but makes reply behaviour more transparent. Showing all headers or the whole message source just to view MFT or MRT is cumbersome and doesn't count here.

^[4] You can set MFT/MRT manually when composing a message.

^[5] Your MUA can (be configured to) automatically set MFT/MRT in outgoing messages according to the message's receipient list and a preconfigured list of mailing lists you are subscribed to/that mangle Reply-To.

^[6] Configurable via hidden preferences.

Claws Mail

Website: http://www.claws-mail.org/
There's a patch for respecting MFT and MRT, but it is not (and maybe will never be) applied. Claws will probably not support MFT or MRT in the near future. See Bug 1441: Add support for the "Mail-Followup-To"-header

Evolution

Gnus

Website: http://gnus.org/
Gnus Message Manual: Mailing Lists

KMail

Website: http://kontact.kde.org/kmail/
When replying to a message, MFT is not used in the reply-to-all case but in the reply-to-list case.
Bug 59478: Ability to add custom header fields when composing a message
Bug 16270: configure the headers visible in the reader pane
Bug 71438: Composer ought to have checkbox for setting/appending Mail-Followup-To header

Mutt

Website: http://www.mutt.org/
See Mutt Manual: Handling Mailing Lists for documentation.

Opera Mail

Website: http://www.opera.com/mail/

qmail

Website: http://cr.yp.to/qmail.html

Roundcube

Website: https://roundcube.net/
When composing a message you can manually set Mail-Followup-To, but the corresponding item in the header selection dropdown is labeled with just Followup-To.
#1937: Support for Mail-Followup-To header

Seamonkey

Website: http://www.seamonkey-project.org/
See Thunderbird for details.

SquirrelMail

Website: http://www.squirrelmail.org/

The Bat!

Website: http://www.ritlabs.com/en/products/thebat/
Please read this message and followups.

Thunderbird

Website: https://www.thunderbird.net/
2009-12-08: Thunderbird 3.0 released with full Support for MFT and MRT.
The Mozilla wiki has documentation about how to configure Thunderbird for MFT and MRT.
Bug 204339: [RFE] Mozilla Mail should support the setting and reading the mail-followup-to header
MFT support in Thunderbird 1.5 and 2.0 had a minor bug that was fixed in version 3.0.