You can download the Beta here:
The release notes are here:
Some cool stuff, but should you upgrade already? I ran the Firefox 4 beta for what feels like forever and didn’t have any issues with it. It’s nice to get updates whenever they are released, not have to wait for a long long time until the non-beta is out. I’ll sure be upgrading to FF 5 on my home desktop.
- Added support for CSS animations
- Added support for switching Firefox development channels
- The Do-Not-Track header preference has been moved to increase discoverability
- Improved standards support for HTML5, XHR, MathML, SMIL, and canvas
- Improved spell checking for some locales
- Improved desktop environment integration for Linux users
It’s now possible to run ‘extremely beta’ – alpha? Called Aurora. I’m gonna give it a shot :)
It installs another Firefox and gives you a new icon (not the old fox around a blue globe).
Plugins, bookmarks, passwords are saved/kept so that’s cool.
It’s also noticeably faster than Firefox 4.
Besides that it looks just the same. Maybe that’ll change in the near future.