Jan 21, 2011 15:43 GMT  ·  By

Although the initial plan was to release the tenth Beta development milestone of Firefox 4.0 and then move to the Release Candidate stage, it now appears that the next iteration of the open source browser will linger in Beta just a tad longer.

How much longer? Well, for at least one extra release. Fact is that Firefox 4.0 Beta 10 will be followed by Beta 11 and not by the first RC.

Responsible for this are the vulnerabilities that still plague Firefox 4.0, over 90 hard blockers according to a count did by Asa Dotzler, community coordinator for Firefox marketing projects earlier this week.

However, although Mozilla is now planning to add an extra Beta to the 10 planned at the start of the development process, chances are that the company could still meet a late February 2011 release deadline for Firefox 4.0.

“We will release beta 10 as soon as possible during the week of the 24th,” revealed Christian Legnitto, Firefox release manager at Mozilla.

This means that by the end of next week, early adopters will be able to take Firefox 4.0 Beta 10 out for a spin.

According to Legnitto, Firefox 4.0 Beta 11 will follow closely the Beta 10 release, with Mozilla pushing releases at an accelerated pace.

After all, Firefox 4.0 should have been finalized and delivered to end users by November 2010, and the browser vendor is too close to having the project delayed even further into 2011 than just February.

“We will release beta 11 as soon as possible during the week of the 31st,” Legnitto added.

This means that if everything goes well, Mozilla will be done with the Firefox 4.0 Beta phase in just a couple of weeks, after which the company will produce the first RC Build.

Firefox 4.0 Beta 9 for Windows is available for download here.

Firefox 4.0 Beta 9 for Linux is available for download here.

Firefox 4.0 Beta 9 for Mac is available for download here.