Firefox Release

June 7, 2016

Version 47.0, first offered to Release channel users on June 7, 2016

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


  • 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

  • Latgalu [ltg] locale added. Wikipedia tells us there are 164,500 daily speakers.

  • View and search open tabs from your smartphone or another computer in a sidebar



  • 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.

  • XRender is no longer used for rendering web content on Linux as this may cause a regression in remote X performance


  • Developer Information
  • 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

  • Added support for ChaCha20/Poly1305 cipher suites

  • Changes that can affect add-on compatibility

  • Web platform changes

Web Platform

  • WebCrypto: RSA-PSS signature support

  • WebCrypto: PBKDF2 supports SHA-2 hash algorithms

  • cuechange events are now available on TextTrack objects


All Firefox downloads