Today Mozilla Firefox 49 was released. We just installed it in our browser cloud and it's available for cross-browser testing to all our users.

Cross-browser testing in Firefox 49

Try Firefox 49 in Browserling now!

Firefox 49 updated Firefox Login Manager. Improved video performance for users on systems that support SSE3 without hardware acceleration. Added context menu controls to HTML5 audio and video that let users loop files or play files at 1.25x speed. Improved about:memory reports for tracking font memory usage. Removed Firefox Hello.

What's new in Firefox 49?

  • Improvements in about:memory reports for tracking font memory usage.
  • Updated Firefox Login Manager to allow HTTPS pages to use saved HTTP logins. It's one more way Firefox is supporting Let's Encrypt and helping users transition to a more secure web.
  • Added context menu controls to HTML5 audio and video that let users loops files or play files at 1.25x speed.
  • Support of Widevine CDM through the EME API under GNU/Linux.
  • Improved video performance for users on systems that support SSSE3 without hardware acceleration.
  • Added features to Reader Mode that make it easier on the eyes and the ears: Controls that allow users to adjust the width and line spacing of text. Narrate, which reads the content of a page out loud.
  • Improve performance on Windows systems without hardware acceleration.
  • Enhancements for Mac users: Improved performance on OSX systems without hardware acceleration. Improved appearance of anti-aliased Mac OSX fonts.

What changed in Firefox 49?

  • Asynchronous rendering of the Flash plugins is now enabled by default. This should improve performance and reduce crashes for sites that use the Flash plugin.
  • Default search engine changed to Yahoo for Chinese (Traditional) locale.
  • Ended Firefox for Windows support for SSE processors.
  • Ended Firefox for Mac support for OS X 10.6, 10.7, and 10.8.
  • Re-enabled the default for Graphite2 font shaping.
  • Default preference layers.allow-d3d9-fallback set to false, to fix graphics glitches for some users.
  • Block some nonessential Flash plugin content
  • Removed Firefox Hello.

What changed in Firefox 49 developer tools?

  • CSS autocomplete: show more suggestions in autocomplete popup.
  • The Animation Inspector now exposes animation performance information in DevTools.
  • In the about:debugging Add-ons page, the Reload button is only enabled for temporary add-ons. It will be disabled for all other add-ons.
  • Introduced web speech synthesis API.
  • Added a Cause column to the Network Monitor to show what caused each network request.

What changed in Firefox 49 HTML, CSS, JavaScript, DOM, SVG, WebGL, WebRTC, HTTP, Networking, Security and Compatibility?

  • You can now rename IndexedDB indexes. The property is no longer read-only.
  • The RTCPeerConnection.addTrack() method has been updated to allow tracks which are not components of the specified streams to be added to the connection.
  • Beginning in Firefox 49, Firefox, by default, blocks certain kinds of Flash content that aren't necessary for sites to function well.
  • Added support for the <details> and <summary> elements.
  • The TouchList.identifiedTouch() method has been removed.
  • CSS grids implementation has been improved.
  • Support for microdata attributes and the Microdata API have been removed.
  • Added support for the round and space keywords to CSS property background-repeat.
  • The MediaStream.getTrackById() method has been implemented.
  • The Firefox OS-only Data Store API has been removed.
  • The PerformanceObserver API is now activated by default on Nightly.
  • The ES2015 getPrototypeOf() and setPrototypeOf() Proxy traps have been implemented.
  • The method DOMTokenList.supports() has been added.
  • The EXT_color_buffer_float WebGL 2 extension has been implemented.

What was fixed in Firefox 49?

  • Fixed an issue that prevented users from updating Firefox for Mac unless they originally installed Firefox. Now, those users as well as any user with administrative credentials can update Firefox.

What security issues were fixed in Firefox 49?

  • Memory safety bugs fixed in Firefox 49.
  • Don't allow content to request favicons from non-whitelisted schemes.
  • Out-of-bounds read in mozilla::net::IsValidReferrerPolicy.
  • Memory safety bugs fixed in Firefox 49 and Firefox ESR 45.4.
  • Heap-buffer-overflow in nsCaseTransformTextRunFactory::TransformString.
  • Bad cast in nsImageGeometryMixin.
  • use-after-free in DOMSVGLength.
  • Iframe src fragment timing attack can reveal cross-origin data.
  • Add-on update site certificate pin expiration.
  • Full local path of files is available to web pages after drag and drop.
  • Heap-use-after-free in nsRefreshDriver::Tick.
  • crash in mozilla::a11y::HyperTextAccessible::GetChildOffset.
  • use-after-free in nsFrameManager::CaptureFrameState.
  • Heap-buffer-overflow in nsBMPEncoder::AddImageFrame.
  • Heap-use-after-free in mozilla::a11y::DocAccessible::ProcessInvalidationList.
  • Use-after-free in mozilla::nsTextNodeDirectionalityMap::RemoveElementFromMap.
  • Out-of-bounds read in PropertyProvider::GetSpacingInternal.

What's remained unresolved in Firefox 49?

  • Older installations of Websense (before version 8.1) may cause a startup crash for Windows users.

Happy cross-browser testing in Firefox 49!