Apple's third-generation butterfly switch keyboard will only be used on the 2018 MacBook Pro, with owners of earlier models unable to get the updated keyboard as a replacement under the company's service programs or as part of a repair.
The 2018 MacBook Pro keyboard, claimed by Apple to be quieter than the second and first-generation butterfly switch designs used in the 2016 and 2017 MacBook Pro and MacBook releases, won't be offered to owners of earlier models if they are brought into an Apple Store or an Apple Authorized Service Provider for servicing.
Confirmed by AppleInsider sources within Apple corporate not authorized to speak on behalf of the company, the earlier MacBook Pro units will receive the same keyboard design as they already have, not the new version. At this time, only the 2018 MacBook Pro will receive the new design if maintenance is required.
It is unclear why the keyboards cannot be updated, but it is likely the rest of the "upper case" that the keyboard is attached to has some changes in the 2018 version that makes it incompatible with earlier models.
There have been a number of cases where the butterfly key mechanism has caused keyboard issues for the 2016 and 2017 MacBook Pro, as well as the MacBook, including repeated characters, unresponsive keys, and other similar issues. The problems prompted Apple to launch a keyboard service program for the issue, with affected users able to receive free servicing on their notebooks.
The new keyboard is touted as being quieter while typing, likely in part due to the addition of a silicone membrane surrounding each butterfly mechanism. It is plausible the membrane could help prevent dust and debris from interfering with the mechanism, with the lower volume potentially being a side effect of its inclusion.
The membrane is not a perfect seal, however. There are gaps to allow the keycap to connect to the keyboard, and a larger one in the center of the cap.
Other than the membrane, there does not appear to be any changes made to the mechanism itself. It remains to be seen if the issues from the 2016 and less in the 2017 models will continue to manifest at the same rate, or if the membrane can prevent them from happening.
The exclusivity of the new keyboard was first reported by MacRumors, but with later confirmation by AppleInsider's own sources.