The Nintendo Switch successor is reportedly using magnetic Joy-Con controllers, and the Joy-Con controllers currently used with the Switch might not be backwards compatible with it.
According to a report from Spanish outlet Vandal (translated by VGC), it was able to get some details about the Nintendo Switch successor from accessory and peripheral manufacturers. Those companies were apparently able to touch the console through an opaque box, giving them a literal feel for the console without seeing it.
While the console will reportedly be bigger than the current Switch system, it won’t be nearly as big as the Steam Deck. As mentioned, because the magnetic system would replace the rail-based one, it would mean the original Joy-Con controllers will not be backward-compatible. However, this should not be an issue for the Switch Pro Controller, which is said to be compatible with the new system.