The wait for the first Beta build of Firefox 3.6 is over. Mozilla has confirmed officially that it will push Firefox 3.6 out of Alpha and into Beta tomorrow, October 28th, 2009. In this regard, the successor of Firefox 3.5 advances to the next step in its evolution, although the beta stage should have come earlier according to the initial plans made public. In fact, Mozilla was aiming to deliver Firefox 3.6 Beta ahead of the general availability deadline of Windows 7, namely ahead of October 22nd. This obviously wasn’t the case.

Responsible for the delay of Firefox 3.6 Beta’s availability were a large number of blockers, bugs critical enough that they were capable of pushing back the release. Mozilla postponed Firefox 3.6 Beta until it managed to deal with all blockers, and with all the bugs now resolved, it gave the green light to the next development milestone for the next iteration of its open source browser.

Ahead of the official release, Mozilla started combing candidates of Firefox 3.6 Beta for any show stoppers, but no bugs severe enough to postpone the Beta were found. This means that testers and early adopters will be able to download and start running Firefox 3.6 Beta on October 28th.

With the release of Firefox 3.6 Beta, Mozilla becomes the third-party browser developer to tailor its product to the new, evolved Windows Aero graphical user interface in Windows 7. Testers will notice that Firefox 3.6 will make use of Aero Peek, Thumbnail Previews via the Taskbar (Superbar) and Jumplists in Windows 7 just as Internet Explorer 8 does, with the mention that Firefox 3.6 is a work in progress, and the experience might not be as smooth.

According to Mozilla’s current plans, Firefox 3.6 will only have one Beta development milestone and will advance straight to Release Candidate in mid-November 2009. If all goes well, end users could be running the finalized version of Firefox 3.6 by the end of the following month.

The latest releases of Firefox for Windows are available for download here.