[REVISION HISTORY]

Mozilla Firefox and Thunderbird software updates

13 recorded revisions of this situation.

What changed

2026-10-15 09:52 UTC → 2026-10-29 06:32 UTC · added ~~removed~~

On September 29, 2026, Mozilla released Firefox 157, implementing the ‘Project Nova’ visual redesign. This overhaul introduces rounded tabs, menus, and address bars, utilizing pastel gradients and a cohesive icon set. The update brings back a ‘compact mode’ to maximize screen real estate and improves multi-tab workflows through more intuitive tab grouping. Performance improvements include hardware AV1 decoding support for WebRTC video calls to reduce CPU load, alongside fixes for 8-bit HDR video color inaccuracies and audio-video synchronization errors. This version also introduces native support for JPEG XL and improved HDR content rendering. The redesign aims to create a consistent visual language across both desktop and mobile platforms and includes a master toggle to disable generative AI tools. Following the release, it was noted that the update also addresses 38 high-risk security vulnerabilities, including sandbox escapes. Additionally, Mozilla released updates for its Thunderbird email client, including versions 157.0, 153.4.0 ESR, and 140.17.0 ESR. The 140.17.0 ESR release is the final version in its series and includes security fixes and the ability to display remote content in OpenPGP messages encrypted with integrity protection. Subsequent updates expanded the ecosystem, including Firefox 158.0, which introduced a ‘Smart Window’ for faster form filling, improved PDF accessibility on Linux and macOS, and expanded translation support for Albanian, Belarusian, and Filipino. Firefox Developer Edition 159.0 added native macOS sharing integration and enhanced Web Console capabilities. Additionally, the Firefox-based browser Waterfox 6.7.6 released version 6.7.6, incorporating security patches from the Mozilla Foundation and new RSS feed management options. In October 2026, Firefox 159 was released, marking a transition to a two-week major version update cycle. This release patched 167 vulnerabilities, including 108 high-risk flaws, and addressed memory leaks in web applications like Zoom.

Versions

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