Mozilla rolls out Firefox 157 redesign across desktop and mobile

Mozilla began rolling out a redesigned Firefox across desktop and mobile on September 29, bringing the new interface to Firefox 157. The release updates tabs, toolbars, the New Tab page and Private Browsing with new colors, icons and themes under a shared design language.

The update gives users more control over the browser’s appearance and interface density. Mozilla says existing bookmarks, extensions and shortcuts remain in place when the Firefox 157 update arrives.

Compact Mode returns with the redesign, reducing the size of tabs and toolbars. An auto-compact option can switch to the smaller layout on reduced-size screens. Mozilla also added a theme picker, new themes and wallpapers, along with a dedicated New Tab customization space where users can pin and organize shortcuts and choose what appears on the homepage.

The settings sit alongside Mozilla’s broader Firefox AI work, while keeping generative-AI features optional. Mozilla’s AI controls let desktop users manage individual features or enable “Block AI enhancements,” a global setting that blocks current and future generative-AI features. Mozilla says the switch also suppresses related prompts and reminders, and that saved preferences persist across Firefox updates.

The managed features include translations, PDF alt text, AI-assisted tab grouping, link previews and a selectable sidebar chatbot. The controls began rolling out with Firefox 148, before the Firefox 157 redesign, so they are not new to this release. By including them in its description of the redesigned browser, Mozilla makes user choice part of the product update without requiring an AI-first setup.

Firefox head Ajit Varma described the redesign as part of Mozilla’s effort to win users through the browser’s product experience. He said ownership of the Gecko browser stack distinguishes Firefox from Chromium-based browsers, and that Firefox should not keep prompting people to use AI after they turn its AI controls off.

Mozilla has not said when the staged rollout will reach every eligible user or whether every customization feature will be available identically on desktop and mobile. The company also says the redesign has no performance cost, but the opened evidence included no independent benchmark of that claim.