The End of Support Calendar shows Microsoft Operating Systems end of support dates, whether they are the end of mainstream support that updates features and cosmetic changes, or extended support, which ends security fixes and all Microsoft technical support other than old web pages.
Windows 10 Initial Release End of Life
Windows 10 version 1507 was the initial release for Windows 10, released July 29th, 2015. Use the 'Winver' app to read the version number. This version of Windows no longer receives security updates, and should be updated to the current Windows 10 release, or taken offline.