The patent details the technology used to work with two SIM cards, and how to determine the priority between them. According to the description, the card that’s actively used for a call will have the priority over the one that’s used for data at the same time, which is perfectly normal. We don’t want our calls cut short, just so we can receive a Candy Crush invite.
The vast majority of Apple patents never see the light of day, so I’m not holding my breath for a dual SIM iPhone 8. It’s interesting nonetheless, seeing as Apple have been posturing to move away from the physical SIM chip for several years now. Also interesting to note that their patent does not require rebooting the device to use the other SIM chip and features smart switching and prioritisation.
Given, this would be a godsend for many users, I just can’t fathom Apple giving up precious physical space inside an iPhone just to make a small subset of users who would find it “convenient” happy. I mean… I’m sure there are more people would prefer a headphone jack than two SIM cards.