Traditionally, the keys on keyboards have been supported by scissor switches, which consists of crossed pieces of plastic that sit below the key and hold the switch up. These scissor switches help to block dust and debris from affecting the key switch and provide smooth key pressing for users.
Today, modern Apple laptops have phased out scissor switches in favor of butterfly switches. Butterfly switch involve thin interlocking pieces of plastic, with a profile much lower than scissor switches, which allows the keys to rest lower on the keyboard. This makes the MacBooks much slimmer than most other laptops.
Unfortunately, this compact design comes with the tradeoff of the slightest bit of dust causing keys to no longer function. According to an AppleInsider report, these new butterfly switch keyboards are twice as likely to break than keyboards with older switches. Up until now, the only solution offered by Apple was to clean the keyboards with compressed air.
Last Friday, Apple finally gave in and announced an extended keyboard service program, that would fix the faulty keyboards of customers. The increased warranty will last 4 years after the afflicted MacBook was bought, and will replace anything from a single key to the entire keyboard. The problems that Apple will fix include letters or characters repeating unexpectedly, letters or characters not appearing, and key(s) feeling "sticky" or not responding in a consistent manner.
Here is a list of all eligible products:
MacBook (Retina, 12-inch, Early 2015)
MacBook (Retina, 12-inch, Early 2016)
MacBook (Retina, 12-inch, 2017)
MacBook Pro (13-inch, 2016, Two Thunderbolt 3 Ports)
MacBook Pro (13-inch, 2017, Two Thunderbolt 3 Ports)
MacBook Pro (13-inch, 2016, Four Thunderbolt 3 Ports)
MacBook Pro (13-inch, 2017, Four Thunderbolt 3 Ports)
MacBook Pro (15-inch, 2016)
MacBook Pro (15-inch, 2017)