 note that header names are case insensitive so this one s no different than mime version similarly other headers in your list ignoring case here may or may not help that s for experiment to decide it s plausible that case is significant if e g a particular spam mailing package generates unusual case or a particular clueless spammer misconfigures his package i found it made no difference for my testing the brilliance of anthony s just count them scheme is that it requires no thought so can t be fooled wink header lines that are evenly distributed across spam and ham will turn out to be worthless indicators prob near NUMBER NUMBER so do no harm zactly i started off doing clever clever things and as always with this stuff found that stupid with a rock beats smart with scissors every time anthony baxter anthony interlink com au it s never too late to have a happy childhood 