[stop50]

with emailservers, the support is there, but on the application side(webfrontends) often emails are limited to ascii/ansi in most cases. On the domains you can circumvent it by entering punycode. On the user part there is no.

[noctis]

There's this case where the webmail showed a mangled version of the Unicode character, while in the raw email it's correct. That amused me.