Are there any SMTP servers that support the SMTPUTF8 extension? [closed]

RFC 5321 limits email addresses to 7 bit US-ASCII encoding. RFC 6531 (a fairly new spec) allows email addresses in SMTP commands and IMF headers to be encoded in UTF-8. This SMTP extension makes internationalized email addresses (e.g., pelé@example.com) possible.

An SMTP server advertises support for internationalized email by replying to the EHLO command with the SMTPUTF8 keyword:

250-smtp.example.com at your service
250 SMTPUTF8

An SMTP client utilizes this extension with the MAIL command:

MAIL FROM:<pelé@example.com> SMTPUTF8 

Question: Are there any SMTP servers or email clients that support SMTPUTF8?

Solution 1:

Postfix supports a subset of SMTPUTF8 since version 2.12: http://www.postfix.org/SMTPUTF8_README.html

Solution 2:

Edit: This answer is no longer true.

As far as I can tell, at this time (Feb 2013) there are no SMTP servers or email clients that support SMTPUTF8.