Windows 7 is one of Microsofts most popular operating systems. 40.88% are still using it, compared to the 37.44% who have moved to the latest operating system, Windows 10 (according to NetMarketShare's September 2018 data).
Every operating system will eventually reach its end of life, so when will Windows 7 end?
On January 13, 2015, Microsoft ended mainstream support for Windows 7. Extended support will end January 14, 2020.
Wondering what the difference between mainstream and extended support is?
They both define the amount of time Microsoft gives for its Windows operating systems. If your operating system is still within the mainstream support period, it means that Microsoft is still taking care of that version - providing security updates for any bugs, releasing design changes and dealing with warranty claims.
Extended support happens after mainstream support expires. Microsoft stop adding new features and end complimentary support for that version of Windows. However they still provide bug fixes and patches.
Once an operating system has completely ended its life, it is essential that the PC is upgraded as it will no longer continue to have any security threats patched.