Are you still running Windows 8.1 Preview version on a computer or two in your possession? Are any of your end-users?
Tomorrow, January 15th, is the very last day that the preview will work. Tomorrow, the preview expires and unless the PC is updated to the release version of Windows 8.1 or Windows RT 8.1, the PC will just stop working.
If you plan to update today, you have a couple options, but both require that any applications you installed will need to be reinstalled. An upgrade of the preview version of Windows 8.1 will only migrate data and accounts. This is true with any preview version of any operating system, though.
- If you installed the Windows 8.1 (and RT 8.1) preview from the Windows Store, the update is available there.
- If you installed Windows 8.1 preview as part of a volume license download, you'll want to download the released bits and do a fresh installation.
Personally, I have one PC I know of that has the preview version still on it, but it’s an ASUS tablet gathering dust in a drawer somewhere. If I ever use it again (which I highly doubt), I'll just install a brand new operating system.