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 complete list of changes in this release.


Firefox Developer Edition

June 10, 2016

Version 49.0a2, first offered to Firefox Developer Edition channel users on June 10, 2016

For more information about Developer Edition please see this MDN article.


  • Reader Mode can now read articles out loud

  • Improve overall performance on OS X systems without hardware acceleration

  • HTML5 audio and video improvements

    • Files can now be looped through the built-in controls in the context menu
    • Play audio and video at 1.25× speed through the context menu
  • Graphite2 font shaping is enabled by default

  • OS X users who did not originally install Firefox can now update it if they can provide administrator credentials

  • Improved appearance of anti-aliased OS X fonts

  • Windows 7 computers without Platform Update can now use D3D11 WARP

  • Improve video performance on systems without hardware acceleration that support SSSE3 instruction set

  • Adjust the width and line spacing of Reader Mode text



  • Support multiple SVG mask elements as mask images