I was an early contributor to Sovereign and used it for many years, but I found that we kept adding features to it and it got too large for my liking. Now I use docker-mailserver:
I looked at Sovereign a while back, and came to the same conclusion, and ended up going with mail-in-a-box, which is possibly a little too far the other way, but at least very low maintenance.
github.com/sovereign/sovereign
I was an early contributor to Sovereign and used it for many years, but I found that we kept adding features to it and it got too large for my liking. Now I use docker-mailserver:
https://github.com/tomav/docker-mailserver