Enterprise users of Firefox should get ready for the next cycle of Firefox ESR, which will begin on 20 November 2012. The Mozilla developers have clarified their plans for the next release of Firefox ESR (Extended Support Release), the version designed for enterprises and other organisations that require a stable qualified version of the browser for inhouse deployment.
The process, as designed, sees a Firefox ESR release being cloned from the mainstream version of Firefox at a particular point in time, in this case the release of Firefox 17 at the end of November, to create Firefox ESR 17. Then, over the next two cycles of mainstream Firefox development, Firefox ESR is tested and bugs fixed in it creating versions 17.0.1 (alongside Firefox 18 on 8 January 2013) and 17.0.2 (alongside Firefox 19 on 19 February 2013).
rest here