Firefox 157 swaps interface for Nova

Mozilla launches Firefox 157 with a new interface and 38 security fixes. The release includes a compact mode and AV1 decoding in WebRTC.

The new Firefox 157 interface brings new themes, icons and rounded corners. There is also an option to pin sites to the new tab page, as well as a theme manager. The release also includes a version optimized for touchscreens and improved HDR video playback. The return of compact mode was one of the main changes, responding to user requests. Firefox 157 fixes 38 security vulnerabilities, including sandboxing flaws. The update is a significant evolution of the browser, with a new interface called Nova, along with security improvements and new features.

Firefox 157 delivers the biggest Design-Update in years — Image: computerbase.de

Firefox 157 was released on September 29, 2026. The new version brings features that may appeal to users who want a more modern interface and greater browsing security. Mozilla also includes AV1 decoding in WebRTC, which may improve the streaming experience for some users. The release of Firefox 157 is part of a trend of continuous browser updates, with a focus on privacy and performance.

Compact mode also returns with Firefox 157 — Image: computerbase.de

The new interface offers a more modern and customizable experience, allowing users to adjust the browser's look to their preferences. AV1 decoding in WebRTC improves video quality in video calls and streaming, but requires the operating system and encoding software to be up to date.

Comparison

Firefox 157 vs. Firefox 156

Firefox 157 swaps the interface for Nova and fixes 38 security flaws — Image: computerbase.de

Comparison
Item	Firefox 157	Firefox 156
Security	Fixes 38 vulnerabilities	Fixes 35 vulnerabilities
Design	New themes, icons and rounded corners	Old design

Firefox 157: New interface and security fixes

The new interface also features a new compact mode, which optimizes space for multitasking and smaller screens, in addition to reducing the size of tabs and the toolbar to give more room to the page being viewed. Mozilla has also introduced a dedicated alternative that optimizes the browser for touchscreens.