Mozilla hopes to classify the upcoming Firefox 3.6 as a minor update, a move that may sound inconsequential but that in fact might have significant repercussions with Firefox users and the speed the open-source browser is developed.

Mike Beltzner, Mozilla's director of Firefox, in a mailing list discussion that he'd like to call the new version a minor release "to quickly migrate our user base to Firefox 3.6." Minor releases in the past typically have been steps from, for example, 3.5.3 to 3.5.4, but Mozilla is trying to speed up more significant changes and not just fixes for bugs and security holes.

"Firefox 3.6 will be primarily a release with security, stability, speed and capability enhancements, with no visible user interface changes over Firefox 3.5. As such, I think we should consider it as a candidate for a minor update, stretching our definition of what types of updates we can provide using that mechanism," Beltzner said.

Be default, Mozilla automatically distributes minor Firefox updates to be installed after a user prompt. Major updates initially require the user to actively retrieve the new version, though Mozilla gets more active as time passes and older versions reach the end of their support lifespans--January 2010 in the case of Firefox 3.0.

Why change the process? To keep up with changes in the browser world, Beltzner said.

"The pace of technology development in web browsers is speeding up rapidly, and we now face a challenge of ensuring that we can continue to deliver modern web browsing experiences to our users," he said.

And in a position that mirrors the rationale that Google offers for its automatically updating Chrome browser, he added, "Users' expectations of software have changed since the update mechanism was introduced in Firefox 1.5. Many applications that browser users interact with exist in the cloud, with updates pushed frequently and transparently, without consultation. That wasn't the case only a few years ago."

That sounds reasonable, right? Well, it turns out nothing is simple.

One problem is that add-ons won't work with the new version unless they're updated, too, and there are a lot of add-ons in the world. "Add-on compatibility is one of the large reasons why users do not move from one version to another," Beltzner said.

Sure enough, John Barton, an IBM employee who's a member of the group overseeing development of the Firebug add-on widely used in Web site development, raised concerns about moving quickly to 3.6 and the current version 1.4 of the add-on.

"We're a little confused by a Firefox 3.6 that can't decide if it is 3.6 or 3.5.5. If 3.6 is really minor, release it as 3.5.5. Else, well then it's not minor after all," Barton said, though adding, "I support shorter release cycles in Firefox."

Add-on compatibility problems is one reason Mozilla is moving to the new Jetpack extensions system in Firefox 4.0 next year.

One of the big new features in Firefox 3.6, code-named Namoroka, is the arrival of Personas, which lets people customize the browser appearance.

Mozilla said the first beta of Firefox 3.6 is due this weekend or early next week, and Beltzner said there currently are no plans for second beta. The final version is due by the end of the year.