If you did the upgrade with "apt-get upgrade", then it won't have pulled in the new translations (firefox-locale-fi). apt-get upgrade is broken, as it doesn't handle installing new packages at all. You shouldn't be using it to do upgrades.
If you did the upgrade with "apt-get upgrade", then it won't have pulled in the new translations (firefox- locale- fi). apt-get upgrade is broken, as it doesn't handle installing new packages at all. You shouldn't be using it to do upgrades.