If you install only FREE version or only PRO version on your PC, you will see the differences as described here.
However, if you install both versions on the same computer, all features on the FREE version will be unlocked automatically. In this case, you will see the two apps are identical.
We understand that you are working on a project on the FREE app, and you want to be able to use the PRO features on the project you created on the FREE app. This is very simple and you will not lose your data.
FYI, the PRO app and FREE app are two different apps. As per the security policy of Windows 10, the PRO app will not be able to open the project created on the FREE app. Therefore our solution is to unlock all features on the FREE app if user purchases and installed the PRO app on the same computer.
And for your convenience, pls remember to use the PRO app for your new projects.