After the release of Firefox 3.5, millions of copies were downloaded. But users of Firefox 3.0 are now in a dilemma of whether going for the upgrade or not. Since, they want to be sure before upgrading if their favorite add-ons, settings, websites etc are working properly in the new version. The best way to find out the answer is to try out a portable version first.
The portable version is the exact copy of Firefox 3.5 installed version, so it is great for testing out the features before upgrading. You can download the portable version from the PortableApps website. Though this portable version is only compatible with the Windows operating system, Linux users may try it on the Linux operating system using Wine.
The portable version can simply be extracted to a folder on the local computer system or to your USB drive from where it can be started after wards. All the features in the portable version of Firefox works same like in the installed version including the installation of add-ons. If you want to check your old Firefox 3.0 settings in the portable version then you can simply export and import the add-ons and settings using Firefox Environment Backup Extension (FEBE).