Firefox 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 Release

October 13, 2014

Version 33.0, first offered to Release channel users on October 13, 2014

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



  • Various security fixes

  • Fix incomplete downloads being marked as complete by detecting broken HTTP1.1 transfers (237623)



Web Platform


  • PDF.js: With some images, wrong colors could show up. Affects a very small number of PDF

  • Some certificate errors cannot be overridden (1042889)

  • Windows: On some combination of hardware and drivers, the main window could be black. In this case, update your graphics drivers (1083071)

  • Windows: With Avast HTTPS scanning enabled, Firefox will not close correctly (1087674)

  • Windows: Interface may be slow when typing or selecting text (1089183)

All Firefox downloads