Hello!
Did you try this one?
Can scid vs. pc support Chess960 as well?
It looks like version 4.8 still isn't there yet. You can play Chess960, but you still can't castle yet in Chess960. However, it seems they're working on it; In the changelog, it mentions, "Add a patch for Chess960 support (from Ben Hague). Unfinished".
I started playing Chess960 (Fischer Random) recently. I use SCID to keep track of my chess games, and I think it is great for a freeware. Unfortunately, it does not support the modified castling rules of Chess960.
Do you know any chess database software running on Linux which supports Chess960? I just need to be able to move the pieces to transfer games from my scoresheet and replay them later on.