Firefox Beta and Developer Edition
Release Notes

Support for Google’s Widevine CDM on Windows and Mac OS X so streaming services like Amazon Video can switch from Silverlight to encrypted HTML5 video.

Enable VP9 video codec for users with fast machines

Embedded YouTube videos now play with HTML5 video if Flash is not installed.

Allow no-cache on back/forward navigations for https resources

Embedded YouTube videos now play with HTML5 video if Flash is not installed

FUEL (Firefox User Extension Library) has been removed. Add-ons relying on it will stop working.

The browser.sessionstore.restore_on_demand preference has been reset to its default value (true) to avoid e10s performance problems. Because faster is better!

The Firefox click-to-activate plugin whitelist has been removed.

See Firefox run! Review Firefox performance data in about:performance.

Smart multi-line input in the Web Console

Custom user agents supported in Responsive Design Mode

Simulate Push messages in the Service Workers developer tool

View, start,and debug registered Service Workers in the Service Workers developer tool

'Start' button for service workers in about:debugging to start registered Service Workers

Tilt is available as extension on AMO

Added support for ChaCha20/Poly1305 cipher suites

Changes that can affect add-on compatibility

WebCrypto: RSA-PSS signature support

WebCrypto: PBKDF2 supports SHA-2 hash algorithms

cuechange events are now available on TextTrack objects