Hi Rod, the closest thing I have for the v1 to v2 new features summary is this forum post here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3573.1

The full list of v1 to v2 changes would be in the v2 beta release notes, those are collected here:
http://kyticka.webzdarma.cz/3d/moi/doc/V2releasenotes.html

Version 2.5 was an early spin-off of the first v3 beta to make the Mac version.

- Michael