Windows Support Cycles
Microsoft® Support Ending Dates for Retail/OEM Consumer/SOHO Operating Systems and Front Office Software
16 November 2016

Microsoft likes to stop support of it's operating systems on a regular basis to force you to upgrade. Below is a list of some of the common operating systems out there and when support will stop. The one to watch is Windows 7, support for this stops in 2020 with standard support already stopped. You should be thinking about your Window 10 migration plans now.
Operating Systems | Mainstream Support Ends | Extended Support Ends |
Windows 101 | October 13, 2020 | October 14, 2025 |
Windows 8.x2 | January 9, 2018 | January 10, 2023 |
Windows 7 | Expired | January 14, 2020 |
Windows Vista | Expired | April 11, 2017 |
The full sets of dates can be found here.
http://www.allyncs.com/docs/lifecyclesupport.html