POST /manage/v1/user/send_mail Ignores Formatting

Hello all,

I am making use of the POST /manage/v1/user/send_mail User API operation with the following request body:

{
  "id_user":xxxxx ,
  "subject": "Test",
  "message": "Hello\nWorld\n"
}

The email is send successfully to the user but all formatting (in this case the \n characters) are ignored!  This is what the email looks like: 

Any idea how (or if it is possible) to preserve the formatting?

Cheers,

George