Leaked Microsoft documentation provides more info on the updating process
Windows 8.1 Preview will be officially unveiled tomorrow, so most Windows 8 adopters are already checking the web for information on how to deploy the update.The official documentation that reached the web recently reveal that Windows 8 users should basically make the switch to Windows 8.1 Preview via the Windows Store, as this is the safest, easiest, and fastest way to do it.
Separate ISOs will also be offered for those who wish to set up a dual-boot configuration and install Windows 8.1 Preview on a different partition. Here’s what Microsoft says about it.
“There are two ways to install Windows 8.1 Preview: through the Windows Store of through the ISO,” the company wrote.
“If you’re running Windows 8 in one of the 13 languages that the preview is available in, we strongly recommend that you download the preview from the Windows Store. When you install from the Store, you can’t create installation media, but most download the preview directly from the Windows Store,” it added.
“If you are running Windows RT, the only way you can update is through the Store. If you’re running Windows 8 and you don’t use any of the 13 languages the preview is available in, you’ll need to install using the ISO. If you’re running Windows 8 Enterprise, you’ll need to install the preview using the ISO.”
In other words, users are advised to get Windows 8.1 Preview from the Store, with a few exceptions: those running RT or Enterprise, and consumers who wish to dual-boot and install it on a clean partition.
Keep in mind that, if you decide to install Windows 8.1 Preview from a dedicated ISO, you’ll need to input a product key, which is the one you got when you purchased Windows 8. Updating from the Store doesn’t require a key.