I am currently using the Contact Management API to allow subscriptions via our Website, and also sending a 2-step Opt-In 'confirmation' email as one of the processes.

I can't use the same API Client object for Send and Contact Management operations currently as API v3.1 only works with Send API endpoints (any Contact Management endpoints just result in a 404) and Contact Management still uses V3, Send API operations are significantly different from the documentation in v3, to the extent where the v3.1 Examples don't work with the v3 endpoints.

It would be greatly more convenient if v3.1 had a unified Send API and Contact Management API