According to a column in Forbes by Vice-President and Principal Analyst at Atherton Research, Jean Baptiste Su, the 2019 Apple iPhone units will come with a USB-C port which replaces the Lightning port, while Apple will bring back Touch ID fingerprint scanner, but this time it will be under the display.
In addition, the 2019 iPhones could have a smaller notch as has been rumored since last year. Presumably, Apple has been able to shrink down the Face ID modules to trim down the notch size, which is definitely great news for users. One way of shrinking the notch is using a “Time of Flight” module, which is less expensive and easier to the manufacturer.