Mozilla has released Firefox 146, introducing native support for fractional-scaled displays on Linux with Wayland. The update includes enhancements for macOS, Android, and web developers, ahead of its official unveiling on December 9, 2025. Users can download the builds immediately from Mozilla's servers.
Firefox 146 arrives a month after Firefox 145, which ended 32-bit support on Linux. The new version prioritizes improved rendering on Wayland by adding native support for fractional-scaled displays, making visuals more effective on Linux systems.
For macOS users, Firefox 146 enables a dedicated GPU process by default, potentially boosting performance. It also introduces link previews powered by an AI feature that summarizes the start of a page with key points. In France, Germany, and Italy, the address bar now suggests English-language options for holidays and important dates. Additionally, Firefox Labs is activated for all users, independent of study participation or telemetry submission.
Android users benefit from simplified file uploads on websites without specified file types, offering options to select a file, capture a photo, or record audio directly. On Windows, the release addresses a bug preventing tab selection when the cursor is at the screen's top on maximized windows with certain monitors and drops Direct2D support.
Web developers gain several tools: post-quantum key shares in DTLS 1.3 handshakes for WebRTC, compressed elliptic curve points in WebCrypto, and the contrast-color() CSS function for automatic color contrast. The updated Skia library enhances rendering, while new CSS features include text-decoration-trim for adjusting line decorations and the @scope rule for subtree styling. The Inspector now hides unused custom properties by default to reduce clutter. Support for the legacy -webkit-fill-available keyword aliases the standardized stretch keyword, aiding older web content.
Mozilla plans the official announcement on December 9, 2025, alongside Firefox 140.6 and 115.31.0 ESR. Binaries for 64-bit, 32-bit, and ARM64 are available now.