This python dictionary maps Microsoft's Census_OSVersion (str) to a timestamp (datetime.datetime). Use this to add the time when a user's OS was last updated. The Microsoft Malware dataset has 579 unique Census_OSVersion's. This dictionary contains dates for 324 of them which constitutes 99.85% of the Microsoft data. These timestamps were downloaded from https://support.microsoft.com/en-us/help/4043454/windows-10-windows-server-update-history and https://changewindows.org/build/17134 For a dictionary of timestamps for AvSigVersion, go here https://www.kaggle.com/cdeotte/malware-timestamps