not the Kaby Lake one that’s recently landed
Apple just told the world it has no idea who the Mac is for
Owen Williams

This is not entirely true, the Kaby Lake equivalent of the quad-core used in the 15-inch model isn’t even available yet (source).

Also, the Kaby Lake CPUs that are available today have not been around long enough for Apple to include them in the Macbooks, unless they didn’t test everything properly. And let’s just say that rushing products to market didn’t work out so well earlier this year (Samsung anyone?)