In order to minimize the number of possible problems with message encode (e.g. "?" instead of Cyrillic symbols), I recommend to set up an unified universal encoding in the Exchange -
UTF-8.
Quotation from the
TechNet article regarding choosing encoding for outgoing emails:
"Exchange uses the order of precedence as described in the following list to determine the message encoding options for outgoing messages sent to recipients outside the Exchange organization"
1. Mail user or mail contact settings
There are no specific attributes to determine encoding for MailContact and MailUser.
