Boot Runner is fully compatible with Windows 10 starting withBoot Runner v2.2.
You can learn more by reading the Twocanoesposts that explain how to run Boot Runner with Windows 10.
Boot Runner and Windows 10
http://twocanoes.com/press/2015-07-30
Apple Boot Camp No Longer Requires USB Flash Drive to Install Windows in El Capitan
http://blog.twocanoes.com/post/130203487014/apple-boot-camp-no-longer-requires-usb-flash-drive
Installing Windows 10 Preview on 2015 MacBook
http://blog.twocanoes.com/post/121116018908/installing-windows-10-preview-on-2015-macbook