I have Companies I authenticated with against V2. With V3 on the scene, can I safely make V3 API calls with their same tokens? Or do I need to have all of my users re-authenticate themselves?
I would think they are re-usable but during the run-up to V3 I vaguely remember reading/hearing some documentation which suggested otherwise. And I don't want to muck anything up by actually trying it out (it would be bad if Intuit somehow set a flag upon a V3 API call saying "this Company is now V3-enabled, disable V2" or something to that affect).
Yes, the tokens are the same, only the actual REST endpoints changed.
There is no need to get new tokens.