The company had promised 11 betas of the browser, and the 12th was a "just in case" that now seems necessary.
Says Christian Legnitto, Firefox release manager at Mozilla (via Soft):
The current plan is to build [Firefox 4.0 Beta 12] when the remaining betaN hardblockers are done. This is heavily dependent on fix and blocker creation rate.
I will be doing some analysis to give people a possible date range, but as far as development is concerned everything is the same (fix as many betaN hardblockers as quickly as possible).
Beta 11 is set for release to testers this week.
Written by: Andre Yoskowitz @ 5 Feb 2011 2:56