I tried this on my qmail box. When sending to that address from gmail I got back this message "local-part of envelope RCPT address contains utf8 but remote server did not offer SMTPUTF8." Fixing that would probably be a patch.<p>Looking at the maildir created, the directory showed up as ????, if I did a cd to the utf8 string I was able to go into that directory and everything was good. My filesystem is ext4, is there another filesystem that supports utf8 in linux?
Good luck using these with most bank, etc. websites. My phone company won't even accept that a plus-sign is a valid part of the local-part of an email address. Most of the oldschool corporates seem to have email validation rules that were already wrong in the 1990s and they show no sign of wishing to enter the 21st Century.