Mozilla will give Firefox 3.6 the coup de grace next month by automatically upgrading users of that 2010 browser to Firefox 12.
The move isn't a first for the open source developer: A year ago, it gave Firefox 3.5 the same auto-upgrade death blow.
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According to Alex Keybl, Firefox's release manager, the automatic upgrade of Firefox 3.6 to Firefox 12 will take place in early May, although a date has not yet been set.
The decision to push Firefox 3.6 users to a newer edition has been under discussion for several weeks. In late March, Keybl brought it up on a Mozilla planning discussion thread, saying that the proposal was needed to keep users safe while they browsed.
Mozilla issued its final security update for Firefox 3.6 on Jan. 31, and officially retired the browser from support last Tuesday, April 24.
Mozilla has given Firefox 3.6 users plenty of warning, telling them several times over the last months that they need to upgrade because of the impending retirement. The newest such message told Firefox 3.6 users that it was their last warning before Mozilla switched on automatic upgrading.
Besides Firefox 12, which launched Tuesday, users can also turn to Firefox Extended Support Release (ESR), the build that Mozilla crafted to soothe customers, including IT administrators who manage Firefox for their workers, who were unhappy with the every-six-week upgrade cadence of the standard browser.
The current version of Firefox ESR is based on Firefox 10, which shipped in December 2011. ESR receives only security updates during its 54-week lifespan. Except for the patches, Firefox ESR won't change until November 2012, and will be supported with updates until early February 2013.
If users want to keep Firefox 3.6, they must disable updates before the May auto-upgrade. On Windows, that setting is reached by selecting Options from the Firefox menu, then Options again (on the Mac, Preferences from the Firefox menu), clicking the Updates tab, then choosing "Never check for updates."
"Users will be automatically updated unless they have specifically disabled updates," said Keybl in an email reply to questions. "However, we strongly advise our users to upgrade from Firefox 3.6, as they will no longer receive critical security updates."
Firefox 3.6 users will soon see this notice, which tells them that their browser will automatically be upgraded to Firefox 12.
In May 2011, Mozilla automatically upgraded Firefox 3.5 to Firefox 3.6 after the former was retired from support, the first time it had used the tactic to rub out an aged browser. It worked -- Firefox 3.5's share fell dramatically.