I think Octalink V1 was introduced in '96 or '97 on XTR mtb cranks, and V1 is also used on all Octalink road cranks. V2 was introduced around '98, I believe, as Octalink trickled down to XT, etc. in the mountain bike line. So XT and lower Octalink mtb cranks use V2 Octalink, XTR and all road cranks use V1. That's the way I understand it, someone correct any of that if it's wrong. I know I used XT Octalink around '98 (which used V2), and when I've bought Octalink bottom brackets I've always had to make sure I didn't get the same Octalink bb that XTR uses (which would be V1) for my XT stuff-