Working on a server running DBMail 3.0 and found there was a memory leak with IMAPD at least stating ‘Too Many Open Files’ every now and then. Upgrading to 3.1.9 wasn’t as straight forward as I had hoped as libevent2 is now required rather than version 1 so the following were the steps I found that worked for me on FreebSD:-

First remove the old libevent version

cd /usr/ports/devel/libevent
make deinstall

Next, install the new version

cd /usr/ports/devel/libevent2
make install

Finally I then had to patch dbmail to include some libevent2 files

edit src/dbmail.h.in

at
#ifdef HAVE_ENDIAN_H
#include
#endif

add

+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <event2/keyvalq_struct.h>
+#include <event2/event_compat.h>
+#include <event2/buffer_compat.h>
+
+

Finally you can then cd the the extracted tar ball of dbmail 3.1 and run the following

env CPPFLAGS="-I /usr/local/include -I /usr/local/include/event2 -I /usr/local/include/event2/compat -I /usr/local/include/zdb -L/usr/local/lib/event2" LDFLAGS="-L/usr/local/lib/event2" ./configure --with-sieve=/usr/local --sysconfdir=/etc

gmake
gmake install

Hope this helps!

James