Firefox Beta and Developer Edition
Release Notes

The display language for the Firefox application UI is now changeable in the Options page

Added Windows playback support for the AV1 video codec

Added support for the WebP image format

Firefox on Windows can now be installed using an MSI installer

Firefox now supports Handoff on macOS to continue browsing from your iOS device to your Mac

On Linux, tabs can be switched by scrolling in the tab bar

Updated the Content Blocking section in the Privacy & Security Options page and in the Control Center to simplify blocking options for users

Enhanced security for Linux, Android, and macOS users via stronger stack smashing protection being enabled by default

Firefox can now be set to warn when exiting, even when configured to automatically restore the session on the next launch

Memory usage is also now reported for each resource visible in the updated Task Manager page found at about:performance

Added a new Flexbox inspector tool to detect and highlight Flexbox containers and debug Flex items' sizes

All CSS changes made in the Rules panel are now tracked in the new Changes tab

Added support for the Storage Access API on desktop platforms