Apple is going to replace the 3-pin accessory connector with a new 4-pin accessory connector on the 2022 iPad Pro. This was reported by the Japanese edition of Macotacara, and the Chinese DTCHAT showed how the back panel of the new tablet will differ in comparison with the current generation.
It is noted that this connector will help power accessories that connect via the Thunderbolt / USB-C connector, but details are not specified. Its use for MagSafe is unlikely: the current third generation is 5-pin, and the location will make magnetic charging inconvenient.
Given the shifted pin layout in the DTCHAT image, old accessories are unlikely to be compatible with the new model, so you will have to buy a new Smart Keyboard along with the tablet.
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