Mozilla could change the name of Firefox 3.1 to Firefox 3.5, the company has said.
The sheer amount of work that has gone into Firefox 3.1 and the number of new features added make it seem "much more than a small, incremental improvement over Firefox 3", Mozilla said.
The forthcoming third beta version of Firefox 3.1 would still be known as Firefox 3.1b3, though the next beta would be Firefox 3.5b4, if Mozilla decides to make the change.
Some of the new features in Firefox 3.1 include TraceMonkey, a Javascript engine that enables much faster performance, as well as improvements to privacy controls.
Mozilla also announced Firefox 3.0.7, an updated version of Firefox 3, earlier this week.