See what’s new in Firefox!

Release Notes tell you what’s new in Firefox. As always, we welcome your feedback. You can also file a bug in Bugzilla or see the system requirements of this release.

55.0

Firefox Release

August 8, 2017

Version 55.0, first offered to Release channel users on August 8, 2017

Today's release brings innovative functionality, improvements to core browser performance, and more proof that we’re committed to making Firefox better than ever. New features include support for WebVR, making Firefox the first Windows desktop browser to support VR experiences. Performance changes include significantly faster startup times when restoring lots of tabs and settings that let users take greater control of our new multi-process architecture. We’ve also upgraded the address bar to make finding what you want easier, with search suggestions and the integration of our one-click search feature, and safer, by prioritizing the secure - https - version of sites when possible. Read what Nick Nguyen (VP, Firefox Product) has to say about Firefox 55, get historical perspective on the development of WebVR from Sean White (SVP, Emerging Technologies) in this Medium post, and read about all the new features for developers in Firefox 55 on Mozilla Hacks.

We'd also like to extend a special thank you to all of the new Mozillians who contributed to this release of Firefox!

New

  • Launched Windows support for WebVR, bringing immersive experiences to the web. See examples and try working demos at Mozilla VR.

  • Added options that let users optimize recent performance improvements

    • Setting to enable Hardware VP9 acceleration on Windows 10 Anniversary Edition for better battery life and lower CPU usage while watching videos
    • Setting to modify the number of concurrent content processes for faster page loading and more responsive tab switching
  • Simplified installation process with a streamlined Windows stub installer

    • Firefox for Windows 64-bit is now installed by default on 64-bit systems with at least 2GB of RAM
    • Full installers with advanced installation options are still available
  • Improved address bar functionality

    • Search with any installed one-click search engine directly from the address bar
    • Search suggestions appear by default
    • When entering a hostname (like pinterest.com) in the URL bar, Firefox resolves to the secure version of the site (https://www.pinterest.com) instead of the insecure version (http://www.pinterest.com) when possible
  • Updated Sidebar for bookmarks, history, and synced tabs so it can appear at the right edge of the window as well as the left

  • Added support for stereo microphones with WebRTC

  • Pages can be simplified before printing from within Print Preview

  • Updated Firefox for OSX and macOS to allow users to assign custom keyboard shortcuts to Firefox menu items via System Preferences

  • Browsing sessions with a high number of tabs are now restored in an instant

  • Make screenshots of webpages, and save them locally or upload them to the cloud. This feature will undergo A/B testing and will not be visible for some users.

  • Added Belarusian (be) locale

Fixed

Changed

  • Made the Adobe Flash plugin click-to-activate by default and allowed only on http:// and https:// URL schemes. (This change will not be visible to all users immediately. For more information see the Firefox plugin roadmap)

  • Firefox does not support downgrades, even though this may have worked in past versions. Users who install Firefox 55+ and later downgrade to an earlier version may experience issues with Firefox.

  • Modernized application update UI to be less intrusive and more aligned with the rest of the browser. Only users who have not restarted their browser 8 days after downloading an update or users who opted out of automatic updates will see this change.

Developer

  • Sites that don’t use SSL can no longer access Geolocation APIs to determine a user’s physical location

Developer Information