[claudius]

It is not possible to assign copyright in German IP law, it is non-transferable and tied to the creator of the work or his heirs. There are some ways around this for purely software projects, e.g. the FSF Europe has a license agreement, which covers pretty much everything and should be enough for nearly all uses.

However, similar agreements (i.e. an artist allowing a record company to use his song however they wanted) signed in the 70s have been found to not extend to ‘digital’ uses, of e.g. music, by German courts as this use case did not exist yet at the time the license was granted.

I’m really saying that this is an annoyingly complicated matter and best avoided by not requiring relicensing – and I’m not a lawyer, of course (and also too lazy to find references now).

And, naturally, there is the issue whether you trust the FSF enough to do the right thing.