Regex filter not working


We’re trying to move to Virtualmin, but are facing an annoying issue. We can’t get email filters to work with regex.
One of our email filters looks like this:

  • ^Subject: [[\w\d]] Account Suspended
    “$HOME/Maildir/.Account Suspension/”

When recieving an email called “[] Account Suspended”, it won’t get filtered at all. It just ends up in the inbox.

Why could this be?

I’ve tested a bit further, and it seems that procmail isn’t too keen about \w\d.
If I change the regex to be
[] Account Suspended
everything works as it should. This is not a viable solution for us, though.

I’ve even tested with just
as the regex, but somehow it’s not a match when I send an email with the subject ‘’.

Seems to be working with the following:

[[a-z0-9]] Account Suspended

Any reason why \w and \d won’t work?