Use encoding:     | If your message contains:
   ------------------------------------------------------------
   7bit              | Only 7-bit text, all lines <1000 characters
   8bit              | 8-bit text, all lines <1000 characters
   quoted-printable  | 8-bit text or long lines (more reliable than "8bit")
   base64            | Largely non-textual data: a GIF, a tar file, etc.