Although Firefox 3.5 (formerly Firefox 3.1) is still in beta, Mozilla is already developing Firefox 3.6 code-named Namoroka. Slated for an early-to-mid 2010 release, the browser will be marketed as Firefox.next (FX) moniker in a nod to new technologies set to take Firefox to the next level.

Not long ago Mozilla changed the release cycle of Firefox, so that major new versions (Firefox 5, 6 and so on) will be released every 2-3 months. Currently, the latest alpha release is Firefox 6 Aurora, while the latest beta development version is Firefox Beta 5, which has made it into the Firefox Next PPA already. Installing this version should be very easy if you follow the next steps.

Firefox 3.6 is scheduled for release as a stable version in November 2009, so this release is just a preview, the starting point for development of Firefox 3.6.

"The second developer milestone of the next release of Firefox - code named Shiretoko Alpha 2 - is now available for download. Shiretoko is built on pre-release version of the Gecko 1.9.1 platform, which forms the core of rich internet applications such as Firefox. Please note that this release is intended for developers and testers only..."

"This week Mozilla released the first beta of Firefox 3. Originally scheduled for mid July, the delay responds to the very long list of features this new version brings. Eight alphas and an estimated 14 months under development are both firsts for a Firefox upgrade but again are necessary for the amount of improvements and new features Firefox 3 will bring..."

Mozilla has released a fifth Firefox 4.0 development preview , labelled Firefox 3.7 Alpha 5, based on the latest Gecko web rendering platform. This alpha adds support for the WebM video format, and there are 64-bit builds for Linux and Mac OS X

Firefox for Mobile (codenamed Fennec) is the name of the build of the Mozilla Firefox web browser for smaller non-PC devices, mobile phones and PDAs. Firefox for mobile 1.0 uses the same version of the Gecko layout engine as Firefox 3.6.

A beta version of Firefox 4.0 has been released with a new look and new features It's been a while in the coming but a beta version of Firefox 4.0 is now out. The most noticeable changes to the browser are the interface ones. Although the interface changes are not available in all beta versions yet they are included in the Windows-specific release.

Firefox 3 will include some significant changes. It uses version 1.9 of the Gecko rendering engine–which itself hasn't been released yet and which includes the Cairo graphics layer. There are also a wide range of improvements to performance, stability, and security, and it's also going to present several new user facing features.