Apple has released an update for the latest MacBook line to improve various interface fixes and power issues. See the updates below:
EFI Firmware Updates: The Extensible Firmware Interface (EFI) specifies the interface between a computer’s firmware and the operating system. These updates address several issues related to system stability. Further information and installation instructions can be found on Apple’s support page.
SMC Firmware Updates: The System Management Controller (SMC) controls various power-related functions. According to Apple, these updates address the "sensing and accuracy of the MagSafe Power Adapter indicator light, and the battery charge indicator lights." General information and installation instructions for SMC updates can be found on Apple’ssupport page.
MacBook EFI Firmware Update 1.3
MacBook SMC Firmware Update 1.2
MacBook Pro EFI Firmware Update 1.6
MacBook Pro 15-inch SMC Firmware Update 1.2
MacBook Air EFI Firmware Update 1.1
MacBook Air SMC Firmware Update 1.1