How is Transfer-Encoding implemented in Exchange 5.5?
A8: Exchange 5.5 encodes in quoted-printable format or in 7-bit format, as required. Additionally, Exchange 5.5 encodes messages in base64 format if 25% of the message is made up of 8-bit characters (that is, characters that are outside the US-ASCII range). This applies only to the message body; attachments are always base64-encoded.
