In high school swimming here in the US, we can't go a year without changing our diving rules.
|(via LA Times)|
Internationally, it's breaststroke. Ever since FINA allowed a Kitajima to win Olympic gold using a dolphin kick during a pullout, updates in that stroke seem to come along a couple of times annually.
“101.2.3 Kick – After the start and each turn, at any time prior to the first breaststroke kick a single butterfly kick is permitted. Following which, all movements of the legs shall be simultaneous and in the same horizontal plane without alternating movement.
The feet must be turned outwards during the propulsive part of the kick. Scissors, alternating movements or downward butterfly kicks are not permitted except as provided herein. Breaking the surface of the water with the feet is allowed unless followed by a downward butterfly kick.”