Which Windows Vista

Is it true that microsoft have sent out an upgrade for Vista which now means that you can only run Vista Ultimate in parallels. I was going to buy Parallels and run Vista Home Premium (OEM) or does the Windows version have to be a retail version.

 

You see at vistas eula it is not prohibited to install the home or premium version on virtual maschines.

By my self it is possible to install these versions at home but with same vista dvd not at work. I don´t know the difference only the result. Could someone explain this?

You could test it with trial version ;-)