Firefox 145 brings PDF comments and improved fingerprinting protection

Mozilla has released Firefox 145.0, expanding the browser with several new features. Among other things, the developers have integrated a PDF annotation function and links that lead directly to highlighted text passages on websites. In parallel, the Extended Support Releases 140.5 ESR and 115.30.0 ESR are being released with security patches.

The new PDF function allows users to add, edit, and delete comments directly in the browser within PDF documents. A comment sidebar is intended to provide an overview of all annotations and enable quick navigation between the marked passages. The feature is available directly in the integrated PDF viewer.

With the “Copy Link to Highlight” function, users can highlight text on websites and generate an individual link via right-click. If a third party accesses this link, the browser will automatically highlight the corresponding text passage. This is intended to facilitate precise sharing of information from longer articles or documents.

Significantly fewer browser fingerprints

Firefox 145 is also intended to further improve data protection by Mozilla reducing browser fingerprinting. According to Mozilla, the new protective measures reduce the percentage of individually identifiable users by almost half. The improvements take effect in private mode as well as when using the Enhanced Tracking Protection (ETP) function in the “Strict” setting. Additionally, the stateless mode of enhanced protection against bounce tracking is now enabled by default in ETP Strict mode to protect users from redirection techniques used by online trackers. More information on the new security features can be found in a dedicated blog post from Mozilla.

The password management has also been revised: saved passwords can now be accessed and managed directly from the sidebar without needing to open a new tab or window. For tab groups, there is a preview function: moving the mouse pointer over the name of a tab group shows an overview of the contained tabs without having to open the group.

End of support for 32-bit Linux

As already announced in September, Firefox 145 marks the end of support for 32-bit Linux systems. Mozilla justifies this step by stating that most major Linux distributions like Ubuntu and Fedora no longer offer 32-bit support, which increasingly complicates maintenance and testing. Users who cannot switch to a 64-bit system will continue to receive security updates for 32-bit Linux with Firefox ESR 140 until at least September 2026.

The Extended Support Release 115.30.0 ESR will be supplied with security updates until March 2026 and will continue to support older operating systems such as Windows 7 and 8.1, as well as macOS 10.12 to 10.14. These long-term versions are primarily aimed at organizations that rely on stable, long-term maintained browser versions. Mozilla recently announced paid enterprise support for larger organizations, which is expected to be available from January 2026.

Further changes in Firefox 145 include a rounder design for horizontal tabs, which aligns with vertical tabs. A new setting allows links from other applications to be opened next to the active tab instead of at the end of the tab bar.

According to Mozilla, the updates will be distributed on November 11, 2025, via the integrated update function. Details on the security vulnerabilities fixed in all three versions will be published on the Mozilla security page. The complete release notes are expected to appear later on the Firefox website.

(fo)