<P> Microsoft markets Windows 8.1 as an "update" rather than as a "service pack" or "upgrade". However, Microsoft's support lifecycle policy treats Windows 8.1 similarly to previous Windows service packs: it is part of Windows 8's support lifecycle, and upgrading to 8.1 has been required to maintain access to mainstream support and updates after January 12, 2016 . Although Windows 8 RTM is unsupported, Microsoft released an emergency security patch in May 2017 for Windows 8 RTM, as well as other unsupported versions of Windows (including Windows XP and Windows Server 2003), to address a vulnerability that was being leveraged by the WannaCry ransomware attack . </P> <P> Retail and OEM installations of Windows 8, Windows 8 Pro, and Windows RT can be upgraded through Windows Store free of charge . However, volume license customers, TechNet or MSDN subscribers and users of Windows 8 Enterprise must acquire a standalone installation media for 8.1 and install through the traditional Windows setup process, either as an in - place upgrade or clean install . This requires an 8.1 - specific product key . </P>

Which windows 8 feature did microsoft not included in windows 10