I have a template set to send Quoted Printable content encoding. However, when the message arrives, the header indicates it is Base64 encoded instead.
If the character set is defined as being anything other than ASCII, ISO-8859-1, or MacRoman the template will automatically be sent using the Base64 encoding. This is because Quoted Printable is not as efficient as Base64 for non-Latin based characters. Character sets such as Shift JIS (Japanese) will always default to Base64 encoding.