When you install a new version you install the basic database from years ago. A Navdata update to fill the database with the up to date data again should do the trick.
Before you upgrade you should save you Mylog.db3 file and any folders specific to you such as photos, logos, silhouettes, outlines etc as again when you install a version update you get the basic data from years ago. Once installed you can replace the old stuff with the newer versions you have saved.
Clicking on the aircraft like you did, auto-populates the info from the server.
Once again the only difference with V6 over V5 is that it allows USB sticks and the comstation to work with the software. Unless you have this need going to V6 does no difference.
Alan