Microsoft said last year that computers running Windows 8.1 will be eligible for Windows 10 Updates. Microsoft stated that all Computers who have pirated Software will not be eligible for Windows 10 updates. Microsoft has device compatibility for Windows 10. You can check if your Device can use Windows 10 by simply downloading a driver.
However, if you still want to stick to the older version of Windows (say 8.1) for some reason and discover that your new Windows 10 device does not support all drivers for your device, you might be in for trouble.
Here are a couple of ways you can stop automatic updates:
I don't want to update
You can go to Update & Recovery > Choose How Updates Get installed
Don't want to update
Choose the Option from the Drop Down Menu > Never Check for Updates (Not Recommended)
Control Panel > All Control Panel Items > Windows Update > Change Settings
Click on the Drop Down Menu and select "Never Check for Updates( Not Recommended)"
If you Still Choose to Update
Windows will Update only with your consent.
If you changed your mind
Windows will now Update, because you changed your mind