14 DAY TRIAL // Mozilla won't provide any more security updates for Firefox 4.0, because 5.0 is considered a replacement and officially starts the new Chrome-like six-week development cycle.
According to a discussion about Firefox 3.6 and 4.0 support on the mozilla.dev.planning mailing list, Firefox 4.0.1 was the only planned update for the 4.0 branch, and it was replaced by Firefox 5.0 when it came out earlier this week.
"There already has been a 4.0.x release and there may be another if a critical security issue arises that requires a 'chemspill' unplanned emergency fix.
"But that would be an *unplanned* emergency release and not a planned one. The planned security update for Firefox 4 is Firefox 5," Asa Dotzler, Mozilla's director of community development, said.
Mozilla also switched to a silent/automatic update mechanism, but users will be prompted to opt-out if any of their add-ons are not compatible with the new version.
It seems the new life cycle policy hasn't been very well communicated and is not clear even to some Mozilla representatives that handle local communities in languages other than English.
Enterprise users are clearly displeased with the new rapid development process because they have to test each new version for compatibility before deploying it and with a new stable landing every six weeks, it is a lot of work.
Mozilla is jumping head first in release cycle similar to Google Chrome's and doesn't seems to care much about enterprise users, which represent a marginal percentage of its market share.
However, Google's Chris Evans recently told us that Google is working on a Chrome strategy for enterprises, so clearly this market segment matters for the company.
Some people have proposed one-year LTS (Long Term Support) Ubuntu-style releases. For example, to make Firefox 5.0 a LTS release, continue to push out Firefox 6, 7, etc., every six weeks as intended, but backport the security fixes to it.
After a year has passed, make Firefox 13, or whatever is the current version at the time, the new LTS and repeat the one-year process for it. This is something Mozilla is willing to consider down the line if it receives a lot of negative feedback regarding the new life cycle.