I tried to grok what "free silicon upgrades" means and the closest I can get is the SoM package is user upgradable. The actual SoM replacement or upgrade module will cost money but you don't need to buy another laptop or pay someone else to do the upgrade for you. Doesn't really fit my definition of "free" but it's my best guess at what's being announced here.
My initial thought was this laptop is somehow FPGA based and new designs can be loaded with near zero cost to the user at the moment of upgrading. But after reading the article, I don't think that's at all what they're implying.