I don't think there were any changes that happened right at the point Axiom went to the v2 designation -- in other words a v2 is probably the same as a v1 from a few months earlier -- but there were a number of changes that rolled into production over the previous years. I believe the main ones were :

1. Changing the speaker layout from TMTMWW to TTMMWW

2. Changing the cabinet edges, either making them a bit more rounded or a bit less rounded (sorry, I forget)

3. Fine-tuning the crossover design


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