Update: Firefox 5 is now available from the Firefox About page: Firefox menu > Help > About Firefox
Firefox 5 is now available for download, but only via FTP. Even though it is labeled a major update, Firefox 5 looks identical to its predecessor Firefox 4. The only major feature added is the Tracking feature, which you can find in Firefox menu > Options > Privacy tab > select “Tell web sites I do not want to be tracked”. This Firefox 5 is the first Mozilla Firefox in Mozilla’s new release cycle of smaller, more frequent upgrades, as opposed to large ones every few years, to keep their promise to deliver a rapid release development cycle.
The latest version of Firefox includes more than 1,000 improvements and performance enhancements that make it easier to discover and use all of the innovative features in Firefox. This release adds support for more modern web technologies that make it easier for developers to build amazing Firefox add-ons, web applications and websites.
Firefox 5 First Impression
Even though there are a lot of improvements, I tried to test it with Acid3 benchmark test, and the result is the score is still the same: 97/100. For browsing performance, I feel no difference. The only difference is that some of my Firefox add-ons are not working in this new Firefox 5. So now I reverted back to Firefox 4 and will stick with it until Firefox 5 is ready and stable.