Windows 8.1 has involved updating Windows 8/RT-based PCs and devices to the new system, you can also perform an upgrade of sorts from Windows 7. In the Windows 8.1 Preview, at least, these options are limited, however, to a clean install or a partial...
http://www.ebrahma.com/2013/10/upgrade-to-windows-8-1-from-windows-7/Labels: Choose-what-to-keep, Choose-your-settings, Download-and-run-Upgrade-Assistant, Install-updates, Install-Windows-8.1, Review-the-compatibility-report, sign-in, Start-the-upgrade, To-run-Upgrade-Assistant, Upgrade-to-Windows-8.1-from-Windows-7, Use-express-settings, Windows-7, Windows-8.1