Windows 10 to be free Windows 10 to get 'holographic' headset and Cortana - BBC News
Nice! Surprised they are offering it free back to Windows 7 devices. 
Regards 
I imagine one of the reasons is to provide an incentive to move their user base forward.
I was planning to use W7 for at least 5 more years, the W7 support period. Probably longer, if the computer didn’t die. It’s completely stable and performs well. Really well with Cubase, now that ASIO Guard is on my machine. After all, my desktop is not a mobile platform! But, given the price, I will take a look at it within the time window!
I’m wondering if anyone’s made the jump yet and how they’re finding it.
remember, it’s free the first year, after that it will cost you $$$, and it’s only for private persons, companies can not upgrade for free.
Is it even out yet? I haven’t seen it but thought it due this summer or fall.
There are only preview (beta releases) available, this is handy for developers. See Microsoft.com for release planning