With Microsoft making Windows 8.1 available through MSDN, I thought I'd try upgrading an existing Windows 8 instance. The process was very smooth:

  1. I downloaded the appropriate .iso
  2. Opened the .iso file in Windows 8
  3. Ran setup.exe
  4. Entered license key
  5. Chose to keep existing settings and applications
  6. Wait a while and reboot
  7. Wait a while and then log in
  8. All done

The only problem I've noticed is that connecting the Mail and Calendar apps to an Exchange server with a self-signed certificate no longer works. I'd previously figured out a way to work around this for Windows 8, but it no longer works for 8.1.