Completely agree with this, my only concern is that an open-source solution increases the likelihood of spam-ridden senders popping up more frequently and becom

Completely agree with this, my only concern is that an open-source solution increases the likelihood of spam-ridden senders popping up more frequently and becoming harder to shut-down as they can spin up instances more easily and get going from a new location more quickly. There is actually some benefit to be had by the process of setting up a mailing service being a little trickier. From a business perspective, it's also a great decision, as it shows customers who outgrow (or are in fear of outgrowing) your SaaS have a first-party path to scale. And you could still make money off those customers if you can offer a strong support/hosting solution. It's a massive win. As an aTech customer with some of their other products in the past, I'm really pleased to see this and I wish them all the best! Also, proud to support fellow Brit tech companies ;)