In what marks yet another advance for Mozilla in the direction of launching the final version of its open source browser next month, the company Friday announced the release of Firefox 4 Beta 9.

Unlike the Beta 8 which included some major changes, the newly-released Beta 9 chiefly features a couple of performance enhancements; one of which is linked to the code that handles the browser's bookmarks and history list.

As per a Mozilla statement pertaining to the Firefox 4 Beta 9, the new beta sports 662 bug fixes or changes - a number that is less than half of the 1,400 changes that the company made in Beta 8, which launched barely around three weeks back.

Though it is officially not clear whether Mozilla will do a 10th beta of the Firefox 4 - which, according to Mozilla's Kraken benchmark test, will be 2.5x faster than Firefox 3.6 - Damon Sicore, head of Mozilla's engineering group, hinted in a Monday post that Beta 9 might be the last.

Sicore said on a Firefox developers' mailing list: "If we can't get bugs to zero in reasonable time, we'll repeat a tenth beta."

Meanwhile, talking about the Firefox 4 in a separate blog post, Johnathan Nightingale, the director of Firefox development, said: "Firefox 4 is good for the Web, good for our users, and puts the heat on other vendors to up their own game. We need to ship it ASAP -- - we want release candidates in weeks, not months."