In May, Microsoft ended support for the original release version of Windows 10 and now it's doing the same for the first major update for the operating system. Windows 10 (version 1511) will no longer receive any more updates from Microsoft, which applies to Windows 10 Home, Windows 10 Education, Windows 10 Pro and Windows 10 Enterprise editions.
The operating system will continue to run, however a lack of security updates means that the Computer is open to potential threats. The solution that Microsoft recommends is to update to the latest version.