Mozilla's upgrade call last month pushed more Firefox 3.6 users to grab a newer edition than any month since June 2011, a Web metrics company said over the weekend.
According to Net Applications, Firefox 3.6's share of all browsers used in December fell by nearly a full percentage point, ending the month with an average of 4.4%, down from November's 5.3%.
Mozilla began urging Firefox 3.6 users to upgrade in early December after twice postponing the offer. The upgrade pitch prompted users to move to Firefox 8, the most recent "rapid release" edition at the time. Since then, Mozilla has launched Firefox 9.
December's decline was Firefox 3.6's largest since June, when the browser lost 2.1 percentage points, and more than three times November's drop. Last month's desertion rate was also twice the average of the months July through November.
Moving Firefox 3.6 users to the rapid release schedule -- where Mozilla issues a new version of its browser every six weeks -- is important to the company, since it still supports the two-year-old browser with security updates. By getting most of its users onto the new timetable, Mozilla will be able to retire Firefox 3.6.
For several months, Mozilla has discussed the idea of putting Firefox 3.6 out to pasture. Last summer, when it announced a plan to continue supporting the aged browser for enterprises -- which had groused that they were unable to keep up with the every-six-week schedule -- it said it would retire Firefox 3.6 after kick starting an "Extended Support Release," or ESR, program.
The current plan is to retire Firefox 3.6 on April 24, 2012, according to information on Mozilla's website.
Firefox 3.6 accounted for 20% of all versions of Mozilla's browser used last month, down from 82% in January 2011, and 32% in July.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His e-mail address is email@example.com.