Mendelson AS2 opensource solution works well. It is pretty robust and easy to configure. At the same time it has some limitations: - GUI is impossible to separate from headless server without purchasing the paid version. - Database files are located in the same folder with config files and other resources, that makes harder to manage them. Nonetheless, it is possible to deal with it even without recompilation, using several tricks. I have been trying to separate immutable parts of Mendelson from variable and config data with Docker containers, and looks like it works. You may search for docker-mendelson-as2 at Github. Anyway, excellent product, thanks!
Very useful project!