That's a big change from the two years it took to move from Firefox 3.5 to Firefox 4. Firefox 5 is part of Mozilla's new rapid release development cycle. This cycle, which is more akin to what Google does with its Chrome browser, promises faster, more iterative updates. With any luck, Mozilla expects Firefox to hit version 7 by the end of the year.
Visually, Firefox 5 looks identical to Firefox 4. Everything we said in our Firefox 4 review applies to this release.
Rather than reinventing the wheel, Mozilla has added better support for web standards, fixed some bugs, made performance enhancements and added a few additional code touches.
The big new features, courtesy of the release notes include:
Support for CSS animations
Better visibility for the Do-Not-Track header preference
Improved canvas and JavaScript support
Better standards support for canvas, HTML5, XHR, MathML and SMIL
Better tuned HTTP idle connection logic
In another move that mimics what Google does with Chrome, Mozilla now has more options for users who want to partake in the beta and testing process. In addition to nightly and beta channel releases, users can also opt to use the new Aurora channel, which will give users access to features before they hit beta, but with limited QA testing that you don't get with nightly releases. This is akin to Chrome's developer channel.
In our tests, Firefox 5 is fast -- even faster than Firefox 4. We're also loving the more frequent update cycle, because it means that the browser will be more able to support the latest and greatest browser features.