New Microsoft documentation has revealed a Group policy and Registry tweak that allows you to specify the specific Windows version you wish to stay on and prevent new feature updates from being installed.
https://www.bleepingcomputer.com/news/microsoft/this-registry-trick-lets-you-block-major-windows-10-updates/
https://www.bleepingcomputer.com/news/microsoft/this-registry-trick-lets-you-block-major-windows-10-updates/