"Internet mail was originally limited to 7-bit ASCII. MIME added support for the use of 8-bit character sets in body parts@ and also defined an encoded-word construct so other character sets could be used in certain header field values. However@ full internationalization of electronic mail requires additional enhancements to allow the use of Unicode@ including characters outside the ASCII repertoire@ in mail addresses as well as direct use of Unicode in header fields like ""From:""@ ""To:""@ and ""Subject:""@ without requiring the use of complex encoded-word constructs. This document specifies an enhancement to the Internet Message Format and to MIME that allows use of Unicode in mail addresses and most header field content."