More secure connections: Firefox can now automatically upgrade to HTTPS using HTTPS RR as Alt-Svc headers.
Full-range color levels are now supported for video playback on many systems.
Mac users can now access the macOS share options from the Firefox File menu.
Support for images containing ICC v4 profiles is enabled on macOS.
Firefox performance with screen readers and other accessibility tools is no longer severely degraded if Mozilla Thunderbird is installed or updated after Firefox.
macOS VoiceOver now correctly reports buttons and links marked as ‘expanded’ using the aria-expanded attribute.
An open alert in a tab no longer causes performance issues in other tabs using the same process.
The bookmark toolbar menus on macOS now follow Firefox visual styles.
Certificate error pages have been redesigned for a better user experience.