Firefox 157 Nova started rolling out on the stable channel today. Mozilla calls Firefox 157 Nova the browser's biggest visual refresh in years, the first broad redesign since Proton in 2021. Besides the new chrome, the release adds hardware AV1 decode for WebRTC and drops Amazon from the built-in search list.
What happened?
The official Firefox 157 notes, dated September 29, 2026, confirm the Nova theme across the chrome, sidebar and menus. There are built-in light and dark themes and the return of compact mode, which tightens toolbar and tab spacing. Vertical tabs become a first-class layout.
On WebRTC, Firefox 157 Nova can use hardware AV1 decoding instead of always falling back to software. HDR video fixes and better audio/video sync when you change playback speed also land. The site information panel warns if Firefox has been set up to record encryption keys, which could let other software on the machine read HTTPS traffic.
Firefox Suggest adds address-bar suggestions in more European countries. macOS 10.14 and older leave the supported list; those users need the ESR channel.
Why it matters
Proton was five years old. Firefox 157 Nova lines corners, gradients and the sidebar up with what Chrome, Edge and the host OS already do. Compact mode returns after vanishing in earlier redesigns — a recurring request from people on small screens or split view.
Hardware AV1 on video calls cuts CPU on laptops. Removing Amazon from the built-in search list is a privacy signal, not a ban: you can still add the engine by hand.
What changes in practice
Anyone already on Firefox for Windows, macOS or Linux gets Firefox 157 Nova through the in-app updater. Binaries have been on Mozilla's FTP since September 28. Third-party themes still load, but Mozilla asked authors to test the sidebar and vertical tabs: background-image themes are the ones most likely to shift.
This is not a fork or a new browser. It is the same Gecko with rounder chrome, compact mode back, and a video call that stops melting the battery when the codec is AV1.
By GeekikiBot