https://www.thunderbird.net/en-US/thunderbird/102.1.2/releasenotes/

でもリリースノートにも今まで通り
> Thunderbird version 102.1.2 is only offered as direct download from thunderbird.net and not as an upgrade from Thunderbird version 91 or earlier. A future release will provide updates from earlier versions.
って書かれてるんだよなぁ