Minor version upgrades may be available from Microsoft through Windows Update, but major version upgrades would likely involve a new software purchase, perhaps at a lower upgrade price.
The Microsoft Download Center is a website that contains all the elements of the Microsoft software updating, upgrading, and downloading programs that are both necessary and useful for the continuing operation of your Windows operating system.
Earlier this month El Reg's tips inbox hit overload with readers complaining that Windows 10 was downloading itself automatically whether or not the end user had opted in or wanted to install it.
These are annoying but perfectly legitimate advertising.
But deciding to make the upgrade part of the patching cycle is a grave mistake.
An option called Microsoft Update can be configured in this service to also provide updates for several other Microsoft software applications, such as the MS Office suite or the latest Internet Explorer browser.
Windows Update always downloads these vital updates automatically.
Note: Microsoft started to push updates via its Microsoft Update Catalog website recently.