ArtRage 2.2.9 was released a few months ago - you had probably updated earlier on your previous OS. But as you've installed from your old installer it would have updated you to the latest automatically.
The feature updates are listed here:
Generally if it's a 2.2.x update, the 'x' part probably means minor bug-fixes or build changes that dont affect the operation of ArtRage features in a significant way.
AndyRage's mantra for graphics engine code:
"Sure - how hard can it be?"