See what landed recently in Firefox Nightly!

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.

55.0a1

Firefox Nightly

March 6, 2017

Version 55.0a1, first offered to Nightly channel users on March 6, 2017

Firefox Nightly gets a new version every day and as a consequence, the release notes for the Nightly channel are updated continuously to reflect features that have reached sufficient maturity to benefit from community feedback and bug reports.

Features listed here may or may not make a final release of Firefox.

New

  • All locales are now available for Nightly

    Bug 1355082
  • Browsing sessions with a high number of tabs are now restored in an instant

    Bug 1345090
  • The Photon project aiming at refreshing the user interface started being implemented in Nightly. These changes are only visible on the nightly channel and will not land in the beta and release channels before at least version 57.

    Bug 1346488
  • Assign custom shortcuts to Firefox menu items on OS X and macOS via System Preferences > Keyboard > Shortcuts

    Bug 429824
  • New feature: make screenshots of webpages, and save them locally or upload them to the cloud

    Bug 1356243
  • Fine-tune your browser performance from the Preferences/Options page.

    Bug 1364070
  • Sidebar (bookmarks, history, synced tabs) can now be moved to the right edge of the window

    Bug 1355331
  • Use virtual reality devices with the web with the introduction of WebVR

    Bug 1218482

Changed

  • Improved printing from within the Reader Mode

    Bug 1362526
  • We've streamlined the default Windows installer. To change installation options, like the destination directory, download an offline installer from the All Downloads page.

    Bug 1365998
  • about:preferences has been cleaned up and reorganized to make it easier for you to find what you need

    Bug 1335907
  • Firefox uses Mozilla Location Service for geolocation

    Bug 1341897
  • Favicons have been moved to a new data store to allow using higher resolution icons. It's not possible to downgrade a newly created profile to a previous version

    Bug 977177
  • The default font for Japanese text is now Meiryo

    Bug 548311
  • Due to changes in storage format, profiles used with Firefox 55 will no longer work with older versions of the browser

    Bug 1357428
  • The application update UI was modernized to be less intrusive and more informative for users using an outdated version of Firefox

    Bug 893505
  • The Flash plugin is now click-to-activate by default and only allowed on http:// and https:// URL schemes. This change will be rolled out progressively and so will not be visible to all users immediately. For more information see the Firefox plugin roadmap

    Bug 1317856

Developer

  • Insecure sites can no longer access the Geolocation APIs to get access to your physical location

    Bug 1072859
Developer Information