Firefox 157 was released on September 29, and it looks different. This is the release that ships Project Nova, Mozilla’s largest visual refresh of the browser in years.

Project Nova

Nova modernises the browser chrome: the toolbar, tab strip, sidebar, and menus get a cleaner, more consistent look. Alongside it come three density modes:

Mode	For
Compact	Small screens and people who want maximum page space
Standard	The default balance
Touch	Touchscreens and convertibles, with larger targets

New built-in light and dark themes come with it, and built-in dialogs (alerts, confirmations, prompts) plus the colour and date pickers now match the page’s colour scheme instead of looking like they belong to a different decade.

Vertical tabs also work better in full-screen mode, and pressing Tab in the address bar now skips over the search engine button.

Media

• Hardware AV1 decoding for WebRTC, so AV1 video calls use the GPU rather than the CPU, which matters for laptop battery life
• HDR video support for 8-bit colour formats
• Better audio and video sync when changing playback speed

On Linux, hardware decoding goes through VA-API, so it depends on a working driver stack; see our Mesa explainer.

Under the hood

• A warning when encryption keys are being recorded, such as through SSLKEYLOGFILE, which is a legitimate debugging tool but also a way to quietly break TLS privacy
• CSS at-rule() in @supports queries, and a chain value for overscroll-behavior

Getting it

Firefox updates itself on most platforms. On Linux, your distribution, Mozilla’s own apt repository, Flathub, or the tarball all deliver it. Our Firefox 156 download page covers the install options, which are unchanged.

Firefox 158 is already in beta, with better PDF output on Linux, and is due on October 13.