I'm sad to say, but there is no German version of v2.2.

While working on the new version, we modders changed a lot of text (not necessarily for the better, in my opinion) which all would need to be translated. If I'm not mistaken, the rights to the German edition of GalCiv 2 belongs to Kalypso Media. So Stardock would need to contact them in order to make a new translation. I don't see this happening.

Still, if the lack of German version isn't a deal-breaker, you can still get v2.2. If you have registered your copy of the game, you should have access to the fully updated English installer in your account on the Stardock Store. If that is not the case, just contact support. They should help you out.