X220 Tablet Windows 8 Compatibility

[BOBfromILLINOIS]

I just purchased a new x220 multitouch tablet, coming to it from a very capable x200 tablet and I absolutely love it. After purchasing the 14.99 Windows 8 upgrade, it installed the Upgrade Advisor on the Windows 7 installation. It warned me that the x220 tablet screen is not fully Windows 8 compatible and that I would not experience the full Windows 8 experience. As I am now typing this on Windows 8 and multitouch seems to be working fine, what is the incompatibility? just wondering.

By the way, is anyone using a screen protector on their tablet? I can't tell for sure if the surface is glass or not. Model is 4299 series.
Thanks.

[GomJabbar]

The latest BIOS update is for Windows 8. That said, I ran Windows 8 preview on my X220 non-tablet without that BIOS update and did not notice any particular issues.