Firefox Beta and Developer Edition
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.

38.0beta Firefox Beta

April 3, 2015

Version 38.0beta, first offered to Beta channel users on April 3, 2015

New

  • New tab-based preferences

  • Share the active tab or window in a Hello conversation - enabled for first half of the beta cycle

  • Keep track of articles and blog posts with the Reading List - enabled for the first half of the beta cycle

  • Ruby annotation support

  • Base for the next ESR release.

Changed

  • autocomplete=off is no longer supported for username/password fields

  • RegExp.prototype.source now returns "(?:)" instead of the empty string for empty regular expressions

  • Improved page load times via speculative connection warmup

Developer

  • Developer Information

  • Optimized-out variables are now visible in Debugger UI

  • XMLHttpRequest logs in the web console are now visually labelled and can be filtered separately from regular network requests

  • WebRTC now has multistream and renegotiation support

  • copy command added to console

Web Platform

  • WebSocket now available in Web Workers

  • BroadcastChannel API implemented

  • Implemented srcset attribute and <picture> element for responsive images

  • Implemented DOM3 Events KeyboardEvent.code

  • Mac OS X: Implemented a subset of the Media Source Extensions (MSE) API to allow native HTML5 playback on YouTube

  • Implemented Encrypted Media Extensions (EME) API to support encrypted HTML5 video/audio playback (Windows Vista or later only)

  • Automatically download Adobe Primetime Content Decryption Module (CDM) for DRM playback through EME (Windows Vista or later only)

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All Firefox Beta downloads