updated 04:37 pm EDT, Tue March 18, 2014
New version integrates security fixes, adds Notification Center
Mozilla has today announced the immediate availability of web browser Firefox 28 for Windows, OS X, Linux, and Android. The new version brings VP9 video decoding to the alternative browser, as well as Notification Center support for web notifications under OS X.
Also added to the browser are volume control for HTML5 audio and video, support for Opus in WebM, discontinuation of spdy/2 in favor of spdy/3, background thread hang reporting, and support for multi-line flexbox in layout, along with various security fixes.
According to Mozilla's Firefox roadmap, Firefox 29 will be available at the end of April.