According to Kuo’s latest research note (via MacRumors), he claims that next year’s iPhones will feature dual SIM support with LTE+LTE connections, and it will also allow for both SIMs to be active simultaneously while only using one set of chips. “Unlike existing DSDS phones, which commonly support LTE+3G connections, we believe next-generation iPhone models will support LTE+LTE connections, in a bid to enhance the user experience.”
This seems to be in line with the way Apple does things, where they might seem like they’re slow to the market with certain features, but when they do they try to come in over the top and offer a slightly better experience. Whether or not this report is true remains to be seen, but Kuo’s track record has been pretty good so far.
However it is unclear if the 2018 iPhone will support dual SIM card slots/trays, or if one will be embedded in the iPhone itself, like we’ve seen with the Apple Watch Series 3 and the newer iPads with cellular capabilities.