I have been playing with s-nail and found there is a more recent release that fixes a couple bugs I ran into (SMIME signing crash, | command), as well as fixing a major CVE. I have been using the new version (14.7.10) with gmail and local mbox.
I don't have a ports diff because I don't want to step on William's toes, I am unsure if the existing patches are stil relevant, and because the new version has an occasional crash when changing folders (at least on IMAP, not sure about local). I plan to report that upstream. I can provide the diff if someone wants to help update the port. Tim