Following up here again. I believe there is confusion, for which I apologize. First, let me say this is different from a dedicated outbound sending IP. A whitelisted authentication IP allows you use a source application's IP address as the login credentials when the app/website does not support usernames and passwords. We customize the account to recognize and accept the incoming mail that originates from that IP address.

It is not related to a dedicated outbound sending IP

However, seeing significant interest in the dedicated IPs, we are updating the program to allow AppSumo customers to add a dedicated IP address to their plan at a discounted monthly rate of $19.99. You can contact SocketLabs support to add this feature.