This means, if you have an English version of Parallels Desktop 16 and want to upgrade it to a German version of Parallels Desktop 17, you can simply purchase the German upgrade, install it on your Mac, and activate it with the upgrade activation key.
You can upgrade Parallels Desktop to any language version of Parallels Desktop 17. The upgrade activation key will be sent immediately to the e-mail address you provided. To upgrade Parallels Desktop to the latest version you will need to purchase an upgrade from the Parallels Online Store. You can install a Windows, Linux, Mac OS X, or any other supported guest operating system in each of your virtual machines, and work with them and their applications side by side with your Mac OS X applications. Parallels Desktop 17 for MAC is a virtualization solution that allows you to create virtual machines on Macintosh computers with Intel processors (1.66 GHz and faster). Why upgrade to Parallels Desktop 17 for MAC?
