Mozilla Firefox 48.0.1

Fixed

• Fix an audio regression impacting some major websites (bug 1295296)
• Fix a top crash in the JavaScript engine (Bug 1290469)
• Fix a startup crash issue caused by Websense (Bug 1291738)
• Fix a different behavior with e10s / non-e10s on <select> and mouse events (Bug 1291078)
• Fix a top crash caused by plugin issues (Bug 1264530)
• Fix an unsigned add-ons issue on Windows
• Fix a shutdown issue (Bug 1276920)
• Fix a crash in WebRTC

New

• Roar for moar protection against harmful downloads! We've got your back
• Process separation (e10s) is enabled for some of you. Like it? Let us know and we'll roll it out to more.
• Add-ons that have not been verified and signed by Mozilla will not load
• GNU/Linux fans: Get better Canvas performance with speedy Skia support. Try saying that three times fast
• WebRTC embetterments:
  • Delay-agnostic AEC enabled
  • Full duplex for GNU/Linux enabled
  • ICE Restart & Update is supported
  • Cloning of MediaStream and MediaStreamTrack is now supported
• Searching for something already in your bookmarks or open tabs? We added super smart icons to let you know
• Windows folks: Tab (move buttons) and Shift+F10 (pop-up menus) now behave as they should in Firefox customization mode
• The media parser has been redeveloped using the Rust programming language

Fixed

• Heyo, Jabra & Logitech C920 webcam users. We fixed those pesky WebRTC bugs causing frequency distortions. Buh-bye, squeaky voice!
• Improved step debugging on last line of functions

Changed

• So long to support for 10.6, 10.7 and 10.8. Now we can focus on where most Mac users are: 10.9. Don't forget to upgrade!
• After version 48, SSE2 CPU extensions are going to be required on Windows
• Au revoir to Windows Remote Access Service modem Autodial

Developer

• WebExtensions support is now considered as stable
• Want to move absolute & fixed positioned elements? (Who doesn't, right?) Now you can with our geometry editor.
• The memory tool now has a tree map view for your debugging pleasure. It's a little bit of "boo" and a whole lot of "ya."
• We're putting the spotlight on the background. Now you can debug WebExtensions background content scripts and background pages
• Content Security Policy (CSP) is now enforced for WebExtensions. (Who's down with CSP?)
• Old and busted: Error Console. New hotness: Browser Console for your debugging pleasure.
• Add-on development just got easier because you can reload them from about:debugging — because we're all about debugging.
• This theme is hot, hot, hot! Say hi to the Firebug theme for Developer Tools.
• Expand network requests from the console panel to view request details in line, so you can see things in context
• Workers can now use the Web Crypto API