Axiom constantly makes little improvements to the products... I think the V2 designation was really an acknowledgement that it was probably time to let the world know about all the changes.

There isn't really any specific big difference between v1 and v2, more like "after about 6 minor changes they started callimg them v2's".

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8