Mozilla late on Thursday began offering Firefox 3.5 to users still running older versions of the browser, the first of what will likely be several attempts to get people to upgrade before support expires for Firefox 3.0.
Firefox 3.5.2, the current version of the edition launched last June, is now being offered to users running 3.0.13, the most up-to-date edition of Mozilla's 2008 browser.
Although users have been able to upgrade to Firefox 3.5 for two months by downloading the new browser or manually triggering "Check for Updates" under the Help menu, Thursday's offer was the first automated update pitch.
When Firefox users get the update offer, they can choose between accepting the update, postponing it 24 hours or declining it. The latter, however, doesn't permanently block future offers. "We might send you another offer again in the future, but it won't be for several weeks or months," explained Mozilla on its developer center.
Last year, Mozilla launched what it calls a "Major Update" offer several times.
Not all users of Firefox 3.0.13 will see the upgrade offer at the same time; Mozilla rolls out such offers slowly at first to make sure its download network can take the traffic.
Firefox 3.0 users have until January 2010 to switch to the newer Firefox 3.5. At that time, Mozilla will halt production of security patches for the older version.
Last year, Mozilla offered the major update for Firefox 3.0 about four weeks after it launched the browser. The delay this time around -- the offer for Firefox 3.5 follows that edition's debut by about six weeks -- was not explained by Mozilla.
Mozilla's eagerness to get users onto the newest Firefox is in stark contrast to Microsoft's policy with Internet Explorer (IE). Even though grassroots campaigns that urge users to dump IE6 are gaining momentum, Microsoft said last week it won't abandon the eight-year-old browser. Several managers in the IE group have cited enterprise reliance on IE6 as the reason why it's not feasible for it to push people to a newer model, such as this year's IE8.
According to data from Web measurement company Net Applications, about 20% of all Firefox users are already running 3.5, while slightly more than 72% are still using Firefox 3.0. The remaining 8% are running versions older than Firefox 3.0.