Chapter 15 Unified Threat Management for FortiOS 5.0 : Intrusion protection : Enable IPS scanning : Updating predefined IPS signatures
  
Updating predefined IPS signatures
The FortiGuard Service periodically updates the pre-defined signatures and adds new signatures to counter emerging threats as they appear.
Because the signatures included in filters are defined by specifying signature attributes, new signatures matching existing filter specifications will automatically be included in those filters. For example, if you have a filter that includes all signatures for the Windows operating system, your filter will automatically incorporate new Windows signatures as they are added.