If you're an MSDN subscriber, we've got some good news for you. Microsoft is now making available official Windows 10 S ISOs for developers, meaning MSDN subscribers can now download, install and activate Windows 10 S on any device.
Microsoft says the availability of these Windows 10 ISOs are primarily for developers and the education market. The availability of these ISOs mean more people can download and use Windows 10 S, without needing to buy a machine that comes bundled with it.
MSDN subscriptions are pretty expensive, but it likely won't be long before those ISOs get mirrored online elsewhere (we don't recommend downloading ISOs from unofficial sources, of course). Microsoft says they will be releasing the ISOs alongside an Update Assistant Tool for existing Education customers next week.
See MSDN Subscriber Downloads
