Official release day was August 16th and the way things are going the successor simply called Firefox 7 might launch as soon as September 27 2011. This is just some six weeks away and Mozilla blog has revealed that Firefox 7 uses less memory compared to Firefox 4, 5 or 6 and that on average it needs 20 to 30 percent less, and sometimes even 50 percent less.
Naturally this means that Firefox 7 is faster and it should also be more stable. Firefox 8 also needs even less memory than Firefox 7, but the difference is not so dramatic. Firefox 8 should enter Beta status on September 27 and it is currently scheduled for November 8th 2011 release date.
This is not all, in case that all goes smooth, even Firefox 9 might show up this year, but this is still not carved in stone. It is currently scheduled to go to Beta 1 on November 8th and to launch on December 20th 2011. Firefox 9 is available as Firefox 9.0a1 version and we will serve you a link below where you can download all the recent betas, alphas and nightly build from version 7 all the way to 9.
You can play with these releases here.