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.

84.0 Firefox Release

December 15, 2020

Version 84.0, first offered to Release channel users on December 15, 2020

We'd like to extend a special thank you to all of the new Mozillians who contributed to this release of Firefox.

2020 was a year like no other. By March, the world dramatically changed. Despite that, we kept our schedule to release a new Firefox every month to keep Firefox working for you. While we eagerly look to the end of 2020, we thought to take stock of this unprecedented year. Along with all that is new with this release, see our list of top features that made 2020 a little easier.

New

  • Native support for macOS devices built with Apple Silicon CPUs brings dramatic performance improvements over the non-native build that was shipped in Firefox 83: Firefox launches over 2.5 times faster and web apps are now twice as responsive (per the SpeedoMeter 2.0 test). If you are on a new Apple device, follow these steps to upgrade to the latest Firefox.

  • WebRender rolls out to MacOS Big Sur, Windows devices with Intel Gen 6 GPUs, and Intel laptops running Windows 7 and 8. Additionally we'll ship an accelerated rendering pipeline for Linux/GNOME/X11 users for the first time, ever!

  • Firefox now uses more modern techniques for allocating shared memory on Linux, improving performance and increasing compatibility with Docker.

  • Firefox 84 is the final release to support Adobe Flash.

Fixed

Enterprise

Developer

  • Developer Information

  • The Network panel is now able to handle unexpected crashes and render useful debugging details such as a related stack-trace. Users can also easily file a bug report by clicking on the available link to help improve the stability of the tool.
    Network Panel Bug Report Submission Screenshot

  • The Accessibility Panel now includes an option for displaying elements in their tabbing order in order to help developers see what elements are focusable when tabbing and in what sequence.

Unresolved

  • macOS users running on Apple Silicon systems may encounter playback errors on encrypted content if the Rosetta system software is not installed.

  • macOS users running Cylance antivirus software may see their Firefox installation get corrupted due to being erroneously flagged as malware.

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