The latest: Beta 12, which was said to be the last beta (after we were originally told that there would only be seven betas) is late and there will be a Beta 13.
I enjoy watching the browser rivalry out there, but I have to admit that I cannot recall anymore which fixes have been applied to which beta version in the past. Beta 12 was scheduled for a Beta build late last week, but that slipped to Tuesday night. Now Mozilla says that the code will sit there for a "couple days " and wait for patches. The current bug count is 15 (at the time of this writing) which is down 7 from 24 hours ago, but up 1 from 72 hours ago.
Earlier this week, Mozilla's Christian Legnitto told Mozilla developers that Beta 12 is likely to be the last beta, but he wouldn't rule out a Beta 13. It turns out there will be a beta 13, as pre-Beta 13 builds surfaced on Mozilla's FTP server. This indicates that Mozilla will miss the RC release target of February. At this point, a March release for the final seems to be almost too optimistic as well.
All right, I get it. The critical bugs need to be fixed, but Mozilla is playing with fire at this time as it delays a browser that is now four months behind schedule and will collide with the release of IE9. Mozilla has lost valuable time already and may now be released even after IE9, which had plenty of pre-releases as well - 7 platform previews, one beta and one RC - but seems to have had a fairly clean development. Firefox 4 may have lost much of its competitive firepower already and the browser needs to be released to avoid further damage.