Please be specific on how this happened. You state this is the release on the home page. What home page? This is not on the official site, thunderbird.net. See also https://support.mozilla.org/en-US/questions/1449692

How it happened: Thunderbird updated and I got the message. I checked my version with the one on thunderbird.net and it's NOT the same. When I wrote my initial message I had only checked with my updating software, Patch my PC Updater (which says I'm using 115.12.1), not Thunderbird itself. It says 127.0 (that was installed 2024-06-19). No update details are available. I read the the link you submitted and will change to another version. Thanks!

Thanks for sharing that, as another user posted similarly yesterday. Patch My PC and a few other auto-updaters have seized on this neutered version as the new standard. I encourage you to somehow separate Thunderbird from that product.

No problem separating those (it's easy in Patch My PC). Do you have any simple solution to downgrade without losing my settings and data?

- I always suggest making a copy of profile first. for windows, that would be - exit thunderbird - copy c:\users\<yourid>\appdata\roaming\thunderbird to somewhere else

then, I would download latest version from thunderbird.net and install over the top of 127. then look for a possible compatibilities.ini file in the profile and delete it. 127 appears as a beta. Let me know how it goes, as I anticipate others will also encounter this. Thank you.

I had this problem and the suggestion was successful. PatchMyPC will no longer look for Thunderbird. After copying the original profile (35jaanfp.default-release) to a different drive, I installed v.115 and set a new profile (19nbhnxc.default-esr). I renamed two compatibility.ini files and renamed the old profile as 19nbhnxc.default-esr. Thunderbird operates normally as 115.12.1

To clean up, I deleted the two compatibility.ini files that I had renamed and the new profile directory. I have also deleted the original profile directory that I copied to a temp location.

THANKS!

Thanks for the status. Much appreciated. Were you able to use the contents from old profile, or did you reinstall the accounts? It's not clear from your post. Thank you.

So I followed the directions and everything worked fine until I tried to re-connect to my Gmail account. It just doesn't work and I'm trying to find a solution. Ps. I downloaded the Microsoft Store version of Thunderbird, maybe the issue with Gmail is to be found there?

On the other hand, this not very kind reply I got in the Patch My PC Updater forum: https://patchmypc.com/forum/index.php?topic=7772.msg18983#msg18983

Thanks for the status. Much appreciated. Were you able to use the contents from old profile, or did you reinstall the accounts? It's not clear from your post. Thank you.

Most of the content, but as implied in my answer above, I had to re-connect to my e-mail accounts.

Suggestion: You may have had reasons to download from the Microsoft site, but I never recommend it because it installs differently from the standard install, the profile is in a different location, and some thunderbird functions do not work.

Suggestion: You may have had reasons to download from the Microsoft site, but I never recommend it because it installs differently from the standard install, the profile is in a different location, and some thunderbird functions do not work.

The problem was that I didn't allow any cookies which lead to a 400 Bad Request. It's now solved. Would probably have worked in the Microsoft Store version too, but to be on the safe side I installed from thunderbird.net. Many thanks for all the help!

I'm glad that all is well. :)