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.


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.


  • 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


  • Disallow non-secure sites from using Geolocation APIs

    Bug 1072859
  • 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
  • The application update UI was modernized to be less intrusive and more informative for users using an outdated version of Firefox

    Bug 893505
  • 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