By Mozilla's schedule, Beta 9 was nearly a month late.

After Firefox wraps up its beta cycle, Mozilla will issue at least one release candidate to shake out any final bugs. The schedule does not show a target ship date for the release candidate.

Nightingale said that he wanted to see a release candidate soon.

"Firefox 4 is good for the Web, good for our users, and puts the heat on other vendors to up their own game," he said in his blog post yesterday. "We need to ship it ASAP -- - we want release candidates in weeks, not months."

Mozilla's biggest rival is also nearing release candidate on its next browser. According to several online sources, Microsoft will deliver the release candidate of Internet Explorer 9 (IE9) later this month, perhaps on Jan. 28.