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 version 1607 End of Extended Support
(Date is approximate)
Windows 10, version 1607, is also known as Build 14393, and was the "Anniversary Update" to Windows 10. After Extended support ends, there will be no more security patches to this version of Windows.