I want to be informed via email as soon as a recipient subscribes or unsubscribes - how does that work?

Receiving details on subscriptions and unsubscribes via email as an account holder is only possible by doing some programming yourself or additional providers.

It's possible to do own programming via REST API. Click here for more details on our REST API Explorer: https://rest.cleverreach.com/explorer/v3/ 
You'll need programming skills for that.

An additional provider who offers IF / THEN in connection with CleverReach is Zapier. You can find the CleverReach shares at Zapier here. Find help and instructions for using Zapierhere.