All Firefox users should update to version 84 as it offers improved security & features.  Also it is noted that Firefox 84 is the last release that will have support for Adobe Flash.

Mozilla Releases Security Updates for Firefox, Firefox ESR, and Thunderbird | CISA

Security Vulnerabilities fixed in Firefox 84 — Mozilla

Firefox 84.0, See All New Features, Updates and Fixes (mozilla.org)

  • 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.