Microsoft gave an early stage, the end of support for Windows 7 in three years, on 14 January 2020 there will be no updates, security updates and no technical support more by Microsoft.
As we know that Windows 10 is replacement Windows OS for Windows 7 and 8 but in December 2016, Windows 7 has market share 48.34% almost a half user in the world still use this version, but Windows 10 still has just 24.36%.
For the predecessor Windows Vista the extended support ends on 11th April this year. Support for Office 2007 is also running out this year. Further details on the life cycles of the different versions of Windows can be found on this Fact Sheet Microsoft.