Hi,

I can base64 encode an HTML email without attachments by adding header Content-Transfer-Encoding: base64. However, when having attachment, header Content-Transfer-Encoding: base64 does not affect, the body part still has Content-Type: text/html; charset="UTF-8" and Content-Transfer-Encoding: quoted-printable while the attachment part has Content-Type: image/jpeg; filename=6145256529176145767_121.jpg; name=6145256529176145767_121.jpg and Content-Transfer-Encoding: base64.

Can you advise on how to set Content-Transfer-Encoding for the body part to base64 in this case?