Kerio wish to make you aware of a bug that may have been affecting email since 1st January 2010.
SpamAssassin 3.2.5 used in Kerio MailServer's Spam Filter contains a bug which means that all emails sent in the year 2010 may get an additional 3.188 spam score points. This could lead to regular messages being marked as spam or blocked by the server.
We would advise that you and your customers implement the following workaround:
Please create a new custom spam rule which will decrease the spam score by -3.2 points for every message containing Received header with substring "2010".
Please note, the workaround will need to be removed once the issue is fixed.
A Knowledge Base article on implementing the workaround and also outlining a solution for this bug can be found here: http://support.kerio.com/kb/557
The Kerio development team are currently finalising a patch for Kerio MailServer 6.7.3 which will resolve this problem. Once released it will be available from Kerio MailServer Downloads.
If you have any queries please do not hesitate to contact the Kerio Support Team