Firefox Beta
Release Notes

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 Beta — English (US)

Your system may not meet the requirements for Firefox, but you can try one of these versions:

Firefox Beta — English (US)

Version 47.0beta, first offered to Beta channel users on April 27, 2016

Support for Google’s Widevine CDM on Windows and Mac OS X so streaming services like Amazon Video can switch from Silverlight to encrypted HTML5 video.
Enable VP9 video codec for users with fast machines
Embedded YouTube videos now play with HTML5 video if Flash is not installed.
Allow no-cache on back/forward navigations for https resources
Embedded YouTube videos now play with HTML5 video if Flash is not installed

FUEL (Firefox User Extension Library) has been removed. Add-ons relying on it will stop working.
The browser.sessionstore.restore_on_demand preference has been reset to its default value (true) to avoid e10s performance problems. Because faster is better!
The Firefox click-to-activate plugin whitelist has been removed.

Developer Information
See Firefox run! Review Firefox performance data in about:performance.
Smart multi-line input in the Web Console
Custom user agents supported in Responsive Design Mode
Simulate Push messages in the Service Workers developer tool
View, start,and debug registered Service Workers in the Service Workers developer tool
'Start' button for service workers in about:debugging to start registered Service Workers
Tilt is available as extension on AMO
Added support for ChaCha20/Poly1305 cipher suites
Changes that can affect add-on compatibility

Get the most recent version

Firefox Beta — English (US)

Your system may not meet the requirements for Firefox, but you can try one of these versions:

Firefox Beta — English (US)