It is understood that extended support will continue until January 10, 2023, and Windows 7 extended support will be completed on January 14, 2020.
Currently, Microsoft's official 'Assistive Technology' page shows that users of Windows 7 or Windows 8.1 can still upgrade to Windows 10 free of charge. The upgrade will be completed on January 16, 2018, for system security and stability updates , You do not upgrade the small partners or upgrade it as soon as possible.
Windows 8.1 Released in October 2013, Remove the Windows 8 users criticized the boot disk, compared to Windows 7, Windows 8.1 compatibility better, boot faster, count as a generation of classic operating system, deadline December 2017, Windows 8.1 users in the Windows system still accounted for about 10%.