Sai,
Thanks for that suggestion, but it doesn't look like it is applicable. Description from that page says in part "the default configuration is tailored to use the server as an edge protocol server (not as an SMTP server for receiving messages from other HISPs or as a relay)". But we are a HISP and do use it as an SMTP server and for receiving messages and as a relay. So that seems to be a dead end unless we want to do a lot of updating.
We are currently using the version at https://github.com/DirectProjectJavaRI/direct-project-stock which we have working (for the most part - although we're still having issues with the relay), but it is very finicky regarding what version of Java we can use. And any attempt to update to a newer version of James (beyond 3.2.0) doesn't seem to work with the old DIRECT 6.0 classes and jar files. (As noted, a case of Java 8 versus Java 11. Or JavaX versus JakartaEE.)
Other suggestions?
Ken