Not totally insurmountable but will require some significant changes. Notably, permissions for accessing things like the user's name and photo are no longer available in the version of the API we use, and unavailable in the new version of the API without verifying yourself as a developer.
They don't seem to be backwards compatible either. So users who have already authenticated wouldn't be able to log in using the new API.
Going to move this to future fix for now for further consideration.