Is there any risks from migrating from the older Castra to this fork?

Yes, 100% there is a risk. This is very much alpha/WIP. My honest analysis:

I think the code is safe and migrating should be OK. Create a backup copy of your save so that you have something to revert to. You as the user have to determine if the issues you're currently facing with Castra are enough of a problem to take a bit of a risk on an early WIP mod.

Hi SGador - there is still some abstract risk but I feel a bit better about recommending this now that I have tried it with my own long-running save and tested more.

My fork does not change any entity names currently, so there's no "migration" issues. I intentionally stayed away from any kind of setting that would like, delete existing enemy artillery or mines, even though that's probably a feature some players would want, for safety reasons.

I also will be responding actively to issues posted here, so if you run into problems, let me know and I will try to fix them.

Happy engineering whatever you decide!