Comment 53 for bug 1850651

Nevertheless, since 68.x breaks compatibility with so many extensions, many of which will never be updated, it would be a nice gesture to release a 60.9.1, given how severely Gmail and Google Calendar are broken on all prior versions. You wouldn't have to rejigger the update process that's already set to lift people up to the 68.x branch; you could simply make 60.9.1 available under https://archive.mozilla.org/pub/thunderbird/releases/ for those who know to look there.

Of the 5 add-ons that I use:
* 1 was updated (I haven't yet had time to test it).
* 1 was reimplemented as a separate MailExtension by a different author (again, haven't yet had time to test the new version to confirm everything still works).
* 1 was apparently updated to the new packaging requirements, but doesn't actually function.
* 2 seem to have been abandoned by their authors and there's a good chance they'll never be updated or reimplemented.

So with only 2 out of 5 of my add-ons (at least theoretically) working, it'd be nice to be able to keep a working version of 60.x around, and just be aware not to view untrusted emails with it, since it won't be getting any more security updates.