Although Microsoft made upgrading from Windows 8 to 8.1 easy and free, the process has to be done through the Microsoft Store. If you want an ISO version of the OS, and don’t have a TechNet or MSDN subscription, you need to engage in a little trickery, which is straightforward enough, but not ideal.
As someone who once bought a brand new Advent laptop with Vista on it, but without any discs I could use to reinstall or repair the OS in the event of trouble, I know how frustrating not having a physical (or digital) copy can be. Newegg is currently offering a "Windows 8.1 Back-up Media disc" for pre-order that could potentially save the day.
Exactly what the disc contains isn’t spelled out (a recovery disc/a full installable copy of the OS/both?), but you will need to have your own Windows 8.1 license key to use it. The disc doesn’t come with one, which is to be expected as the product retails for $14.99. It’s also being offered through AntaresPro for $19.98.
The Windows 8.1 Back-up Media disc is set to be released on the 15 November, so we should find out more about it before then. You can pre-order it from Newegg here.