Just a week after Mozilla shipped Firefox 3.0, the open-source developer has proposed ship dates for the next version that, if approved, would produce an alpha release next month and a final no later than early 2009.

According to a draft schedule discussed at a Tuesday meeting, Mozilla wants to have the first Firefox 3.1 developer preview, or alpha, ready by July, then move to a beta by August. The schedule slates final code delivery in the last quarter of this year or the first quarter of 2009. A month ago, when Mozilla first started discussing Firefox 3.1 internally, Mike Schroepfer, the company's vice president of engineering, said the upgrade's target ship date was the end of 2008.

If Mozilla holds to that plan, Firefox 3.1 would be its first fast-track update, with a development timeline significantly shorter than usual. Firefox 3.0, for instance, launched approximately 20 months after its predecessor, Firefox 2.0.

Previously, Mozilla said that it would be able to meet the shorter deadlines because Firefox 3.1 would be composed of features that didn't make it into Firefox 3.0, but were "nearly complete," Schroepfer said.

In the meeting notes published online Tuesday, Mozilla listed some of the improvements it hopes to slot into Firefox 3.1, including changes to the revamped bookmarking that debuted in 3.0 and modifications to the new amped-up location bar.

Several of the proposed changes, however, rely on improvements to the Gecko engine that underpins Firefox, as well as other applications, such as Mozilla Messaging's Thunderbird e-mail client. Developers are working on Gecko 1.9.1 at the same time as Firefox 3.1, and programmers on the latter project expect some of those refinements will make it into the browser's next upgrade, including additional improvements in JavaScript performance and better compliance with the Acid3 test, which checks how closely a browser follows certain Web standards.

In March, when both Apple and Opera Software ASA touted gains in matching Acid3's requirements with their Safari and Opera browsers, respectively, Mozilla called the race to a perfect score "a puzzle game" and said it wouldn't divert resources from the still-under-construction Firefox 3.0 to match its rivals.

Since the June 17 launch, more than 21.8 million copies of Firefox 3.0 have been downloaded, according to Mozilla's own counter.