When an API commits to /v1 it doesn't mean it will deprecate /v1 when /v2 or /v3 come out, it just means we're committing to supporting older URI strategies and responses.
/v2 and /v3 give you that flexibility to improve without affecting existing customers.
I'd like to introduce more fields or flags to control the behavior as params, not asking user to change the whole base url for single new API.