I just upgraded my windows 8 to 8.1 on Thinkpad x230..and all of the drivers and programme working perfectly even esset antivirus...and IOS was wazor leaked RTM 9600 and activated flawlessly with my valid genuine windows 8 key online.. Go and upgrade rather painful new installation and search for new drivers.. goodluck guys
Good news, so all your applications copied over & are still activated? Have you dumped the windows.old folder yet?