https://wccftech.com/ipad-air-4-specs-switch-to-usb-c/

At this time, the 2018 and the 2020 iPad Pro series are the only ones where Apple has decided to switch to USB-C, getting rid of the Lightning interface. While the iPad Air 3 still ships with Apple’s proprietary port, things might change with the arrival of the iPad Air 4.

A fresh report from the Japanese website Mac Otakara talks about the iPad Air 4 switching over to USB-C. However, the next iPad mini, which at this point, we might as well call it the iPad mini 6 will stick to Lightning. Keep in mind that with the arrival of the iPad Air 3 and iPad mini 5, Apple used its A12 Bionic SoC, the same silicon found in its 2018 iPhone series. While it’s not confirmed what hardware the company will stick when it launches the iPad Air 4, if it gets released next year, it’s possible we might see the A13 Bionic in action.