Apple is believed to be gradually making the move away from Lightning ports and adopting the more universal USB-C ports across all its devices, but only the flagship iPads have been the benefactors of such a move. However, a newly leaked screenshot of an iPhone running iOS 13 beta shows the recovery screen prompt displaying a USB-C port showing the symbol of a USB-C port instead of the traditional Lightning port, hinting at the possibility of Apple switching to the universal standard in its 2019 iPhones.
That said, it is unlikely that Apple will switch all of its iPhones to using the USB-C port, seeing that it makes a fair amount of money selling Lightning accessories. Industry expectations are that while the successors to the iPhone XS and XS Max may switch to USB-C, the 2019 iPhone XR may retain the Lightning port.
That would make the approach similar to how Apple is treating its iPad lineup. Adopting the universal port will also finally allow Apple to adopt faster charging on its iPhones, which is a much-needed feature that its users have been clamouring for. It would also open up the iPhones to a wide range of universal accessories, such as premium headphones and other accessories.
It is also likely that the adoption may not happen in 2019, and the update and backup screen is a part of a future update, with the code already having been put in place.