The 'end of life' (EOL) plan for Firefox 2 is part of Mozilla's policy of ending support for previous versions of a product six months after a new version's release. It is designed to allow Mozilla developers to focus their efforts on the current browser version, Firefox 3, released in mid-May.
For users, the policy means an end to security and stability updates for the existing versions, as well as an end to releases of new features.
Support will also cease for the Gecko 1.8 layout engine that underlies both Firefox 2 and the Thunderbird 2 email client. The move will affect a range of third-party Gecko-based browsers, such as SeaMonkey, the Mac-only Camino and the Unix/Linux browser Galeon.
Mozilla confirmed the move on the web page devoted to older versions of its software, stating: "Firefox 2.0.0.x will be maintained with security and stability updates until mid-December, 2008. All users are strongly encouraged to upgrade to Firefox 3."
Mozilla is pressing on with the transition despite criticisms of Firefox 3 from some quarters, including some organizations that have found the newer browser unusable due to particular bugs. Some users have noted that Firefox 3 appears to be more prone to crashing than the older browser, and has problems with using too much memory. The browser's new location bar has also come in for criticism. Earlier this month, a system administrator for the University of Bergen commented that a bug related to the use of network drives had meant the organization could not install Firefox 3.
Firefox 2 is still receiving significant numbers of bug-fixes in new releases. Last week, Mozilla released Firefox 188.8.131.52 and Firefox 3.0.4, addressing a dozen security flaws, half of which were ranked as critical. Mozilla's current plan is to release only one more update to Firefox 2, version 184.108.40.206.
Mozilla assured developers that support would continue for Thunderbird 2 past December, despite the fact that it is based on the now-outmoded Gecko 1.8 engine.
"Mozilla (in some form) will provide support for Thunderbird based on the official lifecycle policy," said Mozilla's Michael Connor in a recent message to the Mozilla planning mailing list.
The support situation for third-party browsers based on Gecko 1.8 is more ambiguous, according to Firefox director Mike Beltzner. While he acknowledged that Mozilla developers' focus would no longer be on Gecko 1.8, he said third-party developers would still be free to maintain the software and fix bugs.
"EOL doesn't mean 'everyone stop coding and doing reviews', more that 'we don't have a team doing weekly triage on blockers and milestone releases'," Beltzner wrote in a recent Mozilla mailing list post.
In October, Beltzner said two-thirds of Firefox users were already using version 3. Mozilla set a world’s record for its more than eight million downloads of Firefox 3 in June.