This module is a subclass of Email::Simple which does not fold the headers according to RFC2822 but instead outputs every header as one single line. This is necessary when using the append_string method of Mail::IMAPClient to add messages to an IMAP mailbox, because when the Received: header is folded the folded lines trigger some newline business and I find that the rest of the headers are now part of the message. I consider the bug to be in the IMAP server I'm using (CommuniGate Pro), because it should be able to handle the correctly formatted message.