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 system requirements of this release.


Firefox Release

January 26, 2016

Version 44.0, first offered to Release channel users on January 26, 2016

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


  • Firefox can now get Push Notifications from your favorite sites

  • Screenshot commands allow user choice of pixel ratio in Developer Tools

  • Support the brotli compression format via HTTPS content-encoding

  • In the animation-inspector timeline, lightning bolt icon next to animations running on the compositor thread

  • Enable WebM/VP9 video support on systems that don't support MP4/H.264

  • Enable H.264 if system decoder is available

  • Improved warning pages for certificate errors and untrusted connections



  • Support for Direct2D 1.0 has been dropped. Windows 7 users can install the Platform Update to re-enable Direct2D support (to fix font rendering issues)

  • On-screen keyboard support temporarily turned off for Windows 8 and Windows 8.1

  • Stricter validation of web fonts

  • Use a SHA-256 signing certificate for Windows builds, to meet new signing requirements

  • Firefox will no longer trust the Equifax Secure Certificate Authority 1024-bit root certificate or the UTN - DATACorp SGC to validate secure website certificates

  • To support unicode-range descriptor for webfonts, font matching under Linux now uses the same font matching code as other platforms

  • Firefox has removed support for the RC4 cipher


  • The rule view now displays styles using their authored text, and edits in the rule view are now linked to the style editor

  • WebSocket Debugging API and add-on

  • Jump to function definitions in the debugger with Cmd-Click

  • Built-in JSON reader to intuitively view, search, copy and save data without extensions

  • Service Workers API

  • New memory tool for inspecting the memory heap

  • Visual tools for Layout and Styles:

    • Display rulers along the viewport to verify size and position and use the measurement tool to easily detect spacing and alignment problems
    • Use CSS filters to preview and create real-time effects like drop-shadows, sepia, etc
    • Learn more:
  • Visual tools for Animation:

    • View/Edit CSS animation keyframe rules directly in the inspector
    • Visually modify the cubic-bezier curve that drives the way animations progress through time
    • Discover and scrub through all CSS animations and transitions playing on the page
    • Learn more:
  • Right click on a logged object in the console to store it as a global variable on the page

Developer Information


  • Trusteer Rapport is severely impacting the stability of Firefox