root@raspberyypi:/etc/postfix# diff main.cf.20170529 main.cf
13a14
> smtp_header_checks = regexp:/etc/postfix/smtp_header_checks
root@raspberrypi:/etc/postfix# cat smtp_header_checks
/^Subject: .*WAP150/ PREPEND From: WAP150 <wap150@example.com>
/^To:  *$/ IGNORE