Sets the text content of the mailing with the provided id. This function should only be called when the mailing already has html content. If you wish to send text-only-mails, just set a simple space character (” “) as HTML content. Maileon will then send a mail with header “Content-Type: text/plain; charset=utf-8”.
A linebreak can be realized using “carriage return” ( \r ) whereever a linebreak is expected.