If you are using an o;d version of Firefox Portable and wish to Upgrading Firefox Portable to the latest version at the mean time preserve your sitting and add ons ,follow the following steps:
To upgrade to a newer version of Firefox Portable, just install a new copy of Firefox Portable right over your old one. All your data will be preserved. You can use the built in updater as well, but some non-personal files or directories may be left behind. This will be addressed in an upcoming release.
If you're upgrading from Portable Firefox (older name and directories), make a copy of your existing profile folder within the PortableFirefox\Data\profile directory on your portable drive. Then download the new version of Firefox Portable and copy your profile from the old version into the new version within FirefoxPortable\Data\profile.
If you added any plugins or searchplugins, you should copy those directories as well (PortableFirefox\plugins to FirefoxPortable\Data\plugins and PortableFirefox\firefox\searchplugins to FirefoxPortable\App\firefox\searchplugins)