Mozilla just released Firefox 5 on Tuesday, and will not be releasing any more updates (security or otherwise) for Firefox 4 (even though there are a handful of unpatched security flaws), and instead encourages users on Firefox 4 to upgrade to Firefox 5 as soon as possible.
However, Firefox 3.6 will still be supported for the time being (how long exactly is currently undetermined).
[Mozilla retires Firefox 4 from security support - Computerworld](http://www.computerworld.com/s/article/9217837/Mozilla_retires_Firefox_4_from_security_support)
Indeed. I wonder what some organizations will do, since they would have to go through the testing process all over again with FF5. I know of a few organizations in my area which were considering upgrading from 3.6 since FF4 had been out in the wild for a few months. Now…who knows.
Sounds to me like they’ve switched to Chrome’s rapid release schedule because that’s “hip” nowadays. What they don’t seem to have taken into account though is that when packing FF add-ons, the author needs to supply in which browser version it will work (it’s in the install.rdf which is packed in the .xpi file). That means that developers will also have to test new releases very quickly and update their add-on or otherwise it won’t install in the latest and greatest version.
My guess is that some developers will actually do that, but most will just put a very high version number as maxVersion in that file and hope for the best (I know I would).
Chrome doesn’t have this problem, because there is no such thing as a max version in the install meta data (manifest.json) of chrome extensions (indeed, it’s arguable whether that’s a good or a bad thing).
But it’s the cool thing to do, release a new version every couple of months. I mean, Chrome is on version 12 or something now. Just think, in a couple of years we’ll have Firefox 143, at which point they’ll stop support for Firefox 142 :o