April 26, 2016 - JFBConnect v7.0.0 is available now, with several major features including auto-posting, Facebook profile channels and compatibility with Joomla 3.5.1. See the full changelog.
You don't need to. You just need to install the main com_jlinked...zip file as if you were installing for the first time.
Doesn't hurt to uninstall first. Either way, all of your settings will be retained. It should be a pretty smooth upgrade process, but if you run into any issues, just let us know.