Version 3.0 has several interfaces modified, and the layout of the header files has changed. I beta tested version 2.10 (now called 3.0), and the changes required to move from 2.04/2.05 took about an hour for updating Warlords II.
If I remember correctly, 2.04 has one known bug repaired by 2.05 - however, I would recommend using 2.05 as it is the latest and greatest version. I only offer the downloads as a means of regression testing.
