I'm not familiar with the particular website, but do know about the V2 to V3 change. There is a simplistic compatibility scheme that means many sites carry on working (at least for now), but any that are a bit more complex will need work. I've also noticed that some V2 sites that broke at first are now working again (presumably because Google have tweaked their compatibility code).
Unfortunately the code changes for V3 are not straight-forward - and the more complex the app, the worse the pain is.
Bit of a shame that old websites now have to tread to the Google beat to keep working, but hey ho, at least it keeps developers in clover.