Seems to be the deliberate choice to delay automatic update for now. From the release notes: > Thunderbird version 91.0 is only offered as direct download from

Seems to be the deliberate choice to delay automatic update for now. From the release notes: > Thunderbird version 91.0 is only offered as direct download from thunderbird.net and not as an upgrade from Thunderbird version 78 or earlier. *A future release will provide updates from earlier versions.*