If you are using spamassassin without sa-update you will not like to hear that as of 5 days ago spamassassin has pretty much declared open season on all your mails:
Due to an incredibly gross and dirty bit of rule all properly dated mails get an extra 3.6 added to their score. kablam!
and change the regexp for FH_DATE_PAST_20XX to something that doesn't fire
in the near future (like 20[2-9][0-9]). Don't forget
sa-compile if you use compiled spamassassin rules.