Joe Rossignol, MacRumors:
Some customers have been hoping that Apple will start swapping out second-generation keyboards with third-generation keyboards, as part of its service program, but MacRumors has learned that isn’t the plan.
When asked if Apple Stores and Apple Authorized Service Providers will be permitted to replace second-generation keyboards on 2016 and 2017 MacBook Pro models with the new third-generation keyboards, if necessary, Apple said, no, the third-generation keyboards are exclusive to the 2018 MacBook Pro.
This isn’t terribly surprising, as the architecture of the new machines has changed and the swap-out goes way beyond simply swapping keyboards. But it is good to know.
Reading the iFixit teardown, they did change the case in some subtle ways such that the weight and size of the computer, despite bigger batteries, is the exact same as the old one. iFixit speculated they shaved the case a bit.
It’s really unfortunate, as in fact, the new keyboard’s membrane (according to a leaked service document) is indeed designed to prevent debris from entering. (See MacRumors or your other favorite site for details; Loop tends to moderate links away.)
Interestingly Apple filed a patent for this new keyboard design in 2016.
That doesn’t preclude Apple from doing something different later.