New:
- SVG images can be used as favicons
- Support for TSF (Text Services Framework).
- New look for session restore and welcome back page
- Ability to set a profile picture for your Firefox Account.
- Firefox Hello now includes instant messaging
Changed:
- Type 2 Add-ons (Extensions) that have not been signed by Mozilla will be disabled by default. Read more about Add-on signing in Firefox
- Memory overhead of AdBlock Plus has been greatly reduced
- WebRTC now requires perfect forward secrecy
- WARP is disabled on windows 7
- Improved image decoding with performance up to twice as fast on some devices especially while scrolling
- Smoother and more reliable CSS animations via asynchronous animations
HTML5:
- CSS Font Loading API enabled by default
- Copy/Cut Web content from JavaScript with document.execCommand("cut"/"copy")
- MessageChannel and MessagePort API enabled by default
- Navigator.onLine now varies with actual internet connectivity (Windows and Mac OS X only)
- Added support for the transform-origin property on SVG elements
- Implemented Cache API for querying named caches that are accessible window, Worker, and ServiceWorker
Developer:
- Screenshot a node or element from markup view with the Screenshot Node context menu item
- Copy element CSS rule declarations with the Copy Rule Declaration context menu item in the Inspector
- Network requests can be exported in HAR format
- Removed support for binary XPCOM components in extensions, use addon SDK "system/child_process" pipe mechanism for native binaries instead
- Pseudo-Class panel in the Inspector
- View HTML source in a tab
- Quickly add new CSS rule with New Rule button in the Inspector
Fixed:
- Picture element does not react to resize/viewport changes