You would see SDXC and SDUC. For example, all A and W series devices will have SDXC support, whereas most P devices will support 128TB? cards. Right now, the largest capacity I seen was 2TB which is the maximum of the SDXC. So what would happen if you insert a SDUC card into and SDXC card reader? I will imagine nothing, and the reader won’t mount. If I could make a change, I will show a popup that the card is not supported with this reader, and you would need to use a SDUC card reader for the card. Since it will be years before I see a SDUC card, it won’t be common just as 2TB cards aren’t common now.