Does MS Exchange (any version) supports non-ASCII characters in username or domain parts of SMTP email addresses ? For example double byte characters used by Japanese, Chinese etc. ? How about extended-ASCII characters ? Also how about any version of Exchange sold in Japan, China ? 

My google search indicates that it likely doesn't, but I am looking for something specific in MS Exchange documentation that says it. 

My research so far: 

Wikipedia mentions RFCs (RFCs 6530, 6531, 6532, and 6533) that address internationalization. 

Exchange 2010 doesn't support those: http://technet.microsoft.com/en-us/library/ff848256(v=exchg.141).aspx

Also looked at this thread: http://social.technet.microsoft.com/Forums/exchange/en-US/69f393aa-d555-4f8f-bb16-c636a129fc25/what-are-valid-and-invalid-email-address-characters

Hi

As far as I know it is not allowed to use non-ASCII characters in email address.

Cheers