Okay, this is not a real issue or something, its just a question.

My server uses the version 1.1.4 of GalaxySpace and I'm wondering if it is possible to update to the newest version without any problems. I made a whole new copy of my server and tried it out and the mod always errored. Is there some way to make the update work without corrupting anything?

Upgrade to 1.2.5 version only delete the current world and generate a new.

Yeah sure, but is it possible to update the mod in the same world as before? I already built so lot in it and I don't want to lose everything.
Thanks for the response. :)

Many blocks / items may be lost and you will have to get them again.
You also need to remove all the planets and moons, so they regenerates.