I also have the same question.
I've purchased Enpass for Windows 10 (Windows Store) and also for Android. At work I use the traditional Win32 application. So I started Enpass today at work and updated the application to v6.3 (Win32) and after that I was prompted to register. I did it, but it shows Enpass Lite account now.
What will happened when the Windows Store app and also the Android app get the update? Can I register again with the same email address and my account will upgraded to pro? Or can I just login with the already registrated email and it will upgraded to pro?
Hope we get an answer...