http://wccftech.com/microsoft-ends-support-windows-10-1511/

Microsoft promises two feature upgrades for Windows 10 every year, which has resulted in a little too many versions already. However, the company had revealed quite a well thought out release and end-of-service schedule that makes it clear when the next update should be expected and when the previous one will stop receiving any security updates aka monthly Patch Tuesday cumulative releases. The next Windows 10 version currently on the chopping board is Windows 10 version 1511 also known as the November Update. This is the second Windows 10 version that is being put to its deathbed since the release of Windows 10 back in July 2015.

The original Windows 10 (version 1507) stopped receiving any support from the Redmond software maker five months ago. Starting tomorrow, October 10, the company will also end support for users still running the version 1511 that was released in the November of 2015.