For those holdouts that hadn't installed the beta of Drive v3 on DSM 6, I've just had the package out-of-date notification caused by v3 being moved out of the Beta channeland it is now the main version in Package Center.
After updating the package I had Mac Drive clients display an warning on the menubar. Clicking the menubar Drive icon started the update process to client v3.
After updating the package I had Mac Drive clients display an warning on the menubar. Clicking the menubar Drive icon started the update process to client v3.