Microsoft Windows Outlook has a bug whereby the References email header is allowed to grow up to 1012 characters before being split, in violation of the RFC SMTP line length limit. Postfix will automatically split these lines at 998 characters on receipt, whereas Exim will reject the message.
Removing the limit enforcement entirely is not an option since it will create problems when communicating with other servers.
What would be the best strategy in Exim to mimic the behaviour of Postfix in splitting the header?
