No, it would probably function within SmarterMail maybe. But it could definitely fail when talking to other servers via SMTP. There is an RFC we plan on eventually supporting that allows special characters like this in the protocol. However, a change like that requires a top-to-bottom look at all our protocols and our interface.
TL;DR: It may work for certain things, but probably not as a whole.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com