Smail

This release cleans up many issues with the previous one and adds a
few new features, the most important of which are regular expression
(PCRE)-based content filters for both message headers and the message
body. There is a new "error" director driver which gives the postmaster
control over the error message text for specific rejected addresses. The
"pipe" transport now has far more control and flexibility over how it
handles abnormal conditions, allowing it to correctly handle temporary
errors from the likes of the Cyrus IMAP daemon. Bounce messages are now
much more readable.