The priority of the C7 will be whatever entry of you weapon priorities list that says "INFw_C7."
As for what's new in the latest version, I'm really not sure myself, even. There was some tweaking of the magazine check functionality that I can't remember if I put in the previous version or not, so I updated it just to be sure. (If there's a round in the chamber, it won't be seen as if it is in the magazine any more. Basically, you'll need 30+1 rounds in the weapon to count as a full mag.)