The older version doesn't do CHM, but I think it has limited support for PDB. Don't know if it's enough for your needs though.
As far as updates, I don't know for sure. I've seen lots of posts on their Russian forum talking about Book Designer 5. The latest updates the wiki on here has are version 4 updates from 2007. It's possible that development stopped and it's a dead product, but I would double check the official site first.