IDN - Need help

[Per olof Ljungmark]

I am re-posting this - would really like some help here. We need Cyrus
to accept mail with international characters in sender address. If
someone have experience please share, thanks!

This is what Postfix reports when it tries to deliver to Cyrus:

(SMTPUTF8 is required, but was not offered by host XXX
[/var/imap/socket/lmtp])

(can't see anything relevant in the log from Cyrus)

We want it to be delivered but I cannot figure out how - the sender
address has a "ü" in it.

Really grateful for a hint.

Thanks,

//per