I find it interesting that repeatedly I see people in this support forum making exactly the same mistakes over and over.

1. Thunderbird is not a Mozilla product. It has not been for some years now. (the relationship with Mozilla is complex, but that does not change the status of Thunderbird as not a Mozilla product.) 2. Folk having some expectation that the Thunderbird support forum will some how get an addon author that has not updated their addon to reflect changes in Thunderbird to fix their addon. Not going to happen. 3. Support for addons is provided by the addon authors. That is why the addon pages have support links, either web sites, forums or email addresses.

I see two subject editor addons; https://addons.thunderbird.net/en-US/thunderbird/addon/subject-manager/?src=search In this one the author has made it clear they will not be updating their add-on. They have also made it clear they do not understand the framework in which Thunderbird operates, or their rant would not have included so many references to Mozilla.

The other https://addons.thunderbird.net/en-US/thunderbird/addon/edit-email-subject/?src=search has set the support link to a generic page and the home page to the addon page itself. It has no comments from the author at all, so I guess there may be some intent to update this one.

As these two add-ons have apparently have less that 10,000 users between them (about .001% of users) I would not see the feature as one that would offer sufficient demand to be included in the user interface as any sort of priority.

Not that the change has not been requested. See https://bugzilla.mozilla.org/show_bug.cgi?id=562929 but the grandaddy of them all appears to be this one. https://bugzilla.mozilla.org/show_bug.cgi?id=91106

Matt, thanks for responding to my question. Even if it didn't solve the problem, the information was useful, especially the links.

I have this need as well.

I need to edit my subject lines as well.

Thinking of rolling back TB to continue using EditEmailSubject :(

I discovered a workaround -- not beautiful but better than nothing. I forwarded the message to myself and edited the subject in the forwarded message.

Edit Email Subject for TB 68.

Header Tools Lite for TB 68.

https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

To sfhowes: Thank you so much for alerting me to this. I downloaded it and it works! So after waiting 2 months, I'm back in business. Much appreciated both for you and the developer.

sfhowes said

Edit Email Subject for TB 68. Header Tools Lite for TB 68. https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

Thanks from me as well for this solution. I can now edit the subject for incoming messages so that they can be found and spotted easier.