https://www.mozilla.org/en-US/firefox/96.0/releasenotes/
Security Vulnerabilities fixed in Firefox 96 - Mozilla Foundation Security Advisory 2022-01
https://www.thunderbird.net/en-US/thunderbird/91.5.0/releasenotes/
Security Vulnerabilities fixed in Thunderbird 91.5 - Mozilla Foundation Security Advisory 2022-03
デスクトップ版のみ更新 ストア版は未更新
追記
ストア版も更新