"Nike Vaporfly shoes are not banned but Eliud Kipchoge's are"

BBC:

Any new shoe technology developed after 30 April will have to be available on the open market for four months before an athlete can use it in competition.

World Athletics has also introduced an immediate indefinite ban on any shoes that have a sole thicker than 40mm.

...

An immediate indefinite ban has also been introduced on any shoe that contains more than one "rigid embedded plate or blade".

*Buy Vaporfly running shoes at Amazon.