SendReach V3 uses a slighly different API structure to V2 so we have to request all those 3rd Party Applications that have set up API integrations with SendReach to make a couple of modifications to the way they interface with the SendReach API.
The new SendReach API Documentation is available at http://setup.sendreach.com/integrations/sendreach-api-documntation/ and whilst we will get in touch with those with whom we have a contact, please make a request yourself to any Application you have set up API Integration with as a request from a customer is the best motivation around!
In the meantime, if you have followed the detailed guidance on migration you will have moved your subscribers from V2. to V3. and deleted the SUBSCRIBERS from V2. whilst leaving the LISTS themselves still intact in V2. Existing API Integrations will therefore continue to add new subscribers to your V2 Lists until such times as the 3rd party Application modifies the API interface.
Once those modifications are done you can then import the new subscribers from V2 to your V3 Lists.
The V3. Api Keys are accessible from the Main left hand Menu on the Main Dashboard. (Terminology changes – Key = Public – Secret = Private)