 Almost a year after the initial release , Microsoft quietly released the second version . It entered the technical preview stage on 19 July 2010 , and the final build was released on 16 December 2010 . It includes Network Inspection System ( NIS ) , a network intrusion detection system that works on Windows Vista and Windows 7 , as well as a new anti @-@ malware engine that employs heuristics in malware detection . Version 2 @.@ 0 integrates with Internet Explorer to protect users against web @-@ based threats . NIS requires a separate set of definition updates . 
