Mozilla has made Firefox 145 available for download, marking the end of 32-bit support on Linux systems. The release introduces new PDF annotation tools and tab management improvements. Official unveiling is scheduled for November 11, 2025.
On November 10, 2025, Mozilla published the final builds of the open-source Firefox 145 web browser, ahead of its official release on November 11, 2025. This version drops support for 32-bit Linux systems, meaning Mozilla will no longer provide 32-bit builds starting with Firefox 145. The company recommends users switch to 64-bit versions for ongoing updates and support, noting that maintaining 32-bit Linux has become increasingly difficult. Firefox ESR 140, including 32-bit builds, will continue receiving security updates until at least September 2026.
Key user-facing features include enhanced PDF handling, allowing users to add, edit, and delete comments directly in PDF files for notes like summaries, questions, or tasks. A new comment sidebar enables scanning and quick navigation to comments, useful for long documents. Tab groups now offer previews by hovering over the group name, revealing tabs without opening them. A new setting, “Open links from apps next to your active tab,” appears in General > Tabs options for better control over new page placement.
Other updates refine the user interface: the Copy Link to Highlight menu now shares specific web page sections via context menu selections. Horizontal tabs feature a more rounded look, with updated buttons and text inputs in settings. When no extensions are installed, clicking the Extensions button displays a message highlighting extension benefits, linking to the Firefox Add-ons store.
For developers, Firefox 145 adds support for the Atomics.waitAsync proposal for thread synchronization in shared memory, the Integrity-Policy header for sub-resource integrity enforcement, the text-autospace property for automatic character spacing across scripts, and Matroska container support for codecs including AVC, HEVC, VP8, VP9, AV1, AAC, Opus, and Vorbis.
Binaries are available for 64-bit and ARM64 systems, along with source tarballs, from Mozilla’s FTP server. The release accompanies Firefox 140.5 and 115.30.0 ESR.
