Mozilla sent Firefox Version 91.0 to the release channel today. The update includes eleven security updates of which eight are rated high, two moderate, and one rated low.
Firefox ESR was updated to Version 78.13.
To get the update now, select "Help" from the Firefox menu, then pick "About Firefox." Mac users need to select "About Firefox" from the Firefox menu. If you do not use the English language version, Fully Localized Versions (https://www.mozilla.org/en-US/firefox/all.html) are available for download.
References
Security Updates (https://www.mozilla.org/en-US/security/advisories/mfsa2021-33/)
Release Notes (https://www.mozilla.org/en-US/firefox/91.0/releasenotes/?fbclid=IwAR2a97yBFtkfWKsHSg8h6l5HJzV1Ae6z2_3tutumUlHRaak6-V76FoAfM_U)
Rapid Release Calendar (https://wiki.mozilla.org/Release_Management/Calendar)
91.0.1 has been released to fix some stability and security issues
https://www.mozilla.org/en-US/firefox/91.0.1/releasenotes/
Version 91.0.2 has been released to fix a couple of bugs.
Release Notes (https://www.mozilla.org/en-US/firefox/91.0.2/releasenotes/)