|Unless premail has been fixed it illegally encodes multiparts and
|messages. Below is what it violates. This failure will cause your
|PGP/MIME messages or other multiparts to be unreadable by many, standards
|compliant mail readers.
I believe it still has this problem, as well as a few other short-
comings (it can't encode or sign subparts, for instance, only the
whole message). When using it, I just make sure to hand it something
that it will end up valid when premail is through with it.
This is (partly) why I'd like to roll my own with mhn/mhbuild.