The new options for whitelisting/blacklisting and exceptions are great! Thank you.

We would like to be able to test for different types of rejections, as our systems track and report on things that are permanent (e.g., bad address) or temporary (e.g., mailbox full) issues causing email rejections. Within those, there is some capacity for us to track the reason for the temporary or permanent bounce (address, spammy content, remote server issues, etc).

Happy to contribute here, but I thought it would be helpful to discuss with you about approach, rather than just forking and going off on my own, as I suspect this would be helpful to some others.

Thanks. We love the project!