Kerio Technologies today announced Kerio MailServer 6.1, which adds Sender Policy Framework (SPF), Spam Repellent and dual anti-virus scanning to its existing arsenal of virus and spam-fighting tools. The company says Kerio MailServer 6.1 is designed primarily for small and medium-sized businesses and simplifies email, contact and group calendar management to provide improved collaboration for all types of organizations. Pricing for Kerio MailServer starts at US$499 for 20 users.