Firefox Release Notes

Release Notes tell you what’s new in Firefox. As always, we welcome your feedback. You can also file a bug in Bugzilla or see the system requirements of this release.

91.0 Firefox Release

August 10, 2021

Version 91.0, first offered to Release channel users on August 10, 2021

We’d like to extend a special thank you to the 210 volunteers who helped resolve more than 1,200 bugs in the Firefox 91 release. Of the 210 volunteers, 16 developers contributed their first code changes to Firefox as brand new volunteers!

New

  • Building on Total Cookie Protection, we've added a more comprehensive logic for clearing cookies that prevents hidden data leaks and makes it easy for users to understand which websites are storing local information. Learn more

  • Firefox now supports logging into Microsoft, work, and school accounts using Windows single sign-on. Learn more

  • The simplify page when printing feature is back! When printing, under More settings > Format select the Simplified option when available to get a clutter-free page. Learn more

  • HTTPS-First Policy: Firefox Private Browsing windows now attempt to make all connections to websites secure, and fall back to insecure connections only when websites do not support it. Learn more

  • We've added a new locale: Scots (sco)

  • The address bar now provides Switch to Tab results also in Private Browsing windows.

  • Firefox now automatically enables High Contrast Mode when "Increase Contrast" is checked on MacOS

  • Firefox now does catch-up paints for almost all user interactions, enabling a 10-20% improvement in response time to most user interactions.

Fixed

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Web Platform

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