While upgrading from FreeBSD 11 to 12 this weekend I came across a rather surprising error in the logs. warning: connect to Milter service unix:/var/run/milter-regex/sock: No such file or directory Odd, worked before the upgrade, let’s check it out: $ sudo service milterregex restart milterregex not running? (check /var/run/milter-regex/milter-regex.pid). Starting milterregex. ld-elf.so.1: /usr/lib/libmilter.so.6: Undefined symbol "stat@FBSD_1.5" /usr/local/etc/rc.d/milterregex: WARNING: failed to start milterregex What’s it using? $ ldd /usr/local/libexec/milter-regex /usr/local/libexec/milter-regex: libmilter.