An anonymous reader writes: Mozilla today launched Firefox 35 for Windows, Mac, Linux, and Android. Major additions to the browser include room-based Firefox Hello conversations, H.264 (MP4 files) playback on OS X, and integration with the Android download manager. Firefox 35 for the desktop is available for download now on Firefox.com, and all existing users should be able to upgrade to it automatically. As always, the Android version is trickling out slowly on Google Play. Full changelogs: desktop and Android.