It's cool but what I really want, what I'd trade almost anything for, is an all-in-one smtp+dkim+imap mailserver binary written in a non-meme language.
Gmail instantly was happy with my inbound emails. I got on a backscatter blacklist because I didn't immediately drop invalid email addresses at the gateway, but that will time out shortly. And just as I had settled in with the new server, I got to test the update function. This week the entire docker-mailserver project moved to a new repo name on Github, with a new release. A couple of the config files changed names, but nothing much in contents. A docker pull for the new image name, and my mail server was running the fresh release. Happy, happy, happy.
What languages are acceptable then? You may need to provide a definition to prevent confusion.