The older version should be overrided.

hello, when there is an older version listed in the control panel beside the currently installed version this is usually just a leftover entry which didn't get removed properly (the old firefox program won't be present on your harddisk any longer). if you choose to uninstall the old entry, it will probably remove the current version from the harddisk instead. if you do so please make sure that you do NOT check to remove your personal data during uninstall. you'd have to install the current firefox version from www.getfirefox.com afterwards again though...

Thank you for your help.