If you've been using Natural Docs 1.5, then there's a lot of new things for you in 2.0!
Natural Docs 2.0 is a complete rewrite. Perl was getting too unwieldy for what I wanted to do, and the original design had some assumptions baked into it that were very limiting. Since I would need to significantly revamp it to move forward anyway, I took the opportunity to switch to C#. Natural Docs is a decidedly more modern program now, with a back end built on SQLite, multithreaded parsing for extra speed, and unit tests for reliability.
But you don't care about the behind the scenes stuff. Let's get to what's new and cool.