In Windows, type “Defender” in the start menu and it will lead you to Windows Security.
There should be a “Settings” symbol 
in the lower left corner. When you click on it, you will see a window with a link to “Info”. Here you can see the latest virus signature of Defender.
This is the Microsoft “Smart Screen” Torben has described in the german section: mAirList v7.3 public beta: Fehlersuche - #44 by Torben