Chapter 1 What’s New for FortiOS 5.2.1 : Top Features : Flow-based Antivirus
  
Flow-based Antivirus
In FortiOS 5.2, flow-based AntiVirus has been improved to have the same enhanced performance as flow-based antivirus scanning in FortiOS 5.0 while providing the same accuracy and many of the extended features of proxy-based antivirus.
For more information, see “Flow-based Antivirus”.