Apple today released MacBook Air SMC update 2.0 for mid-2013 MacBook Air models, addressing an issue that could cause excessive battery drain when the computer's lid is closed.This update is recommended for MacBook Air (Mid 2013) models.
This update addresses an issue which may cause the battery to drain faster than expected when the lid is closed.
This is the second battery fix released for the 2013 MacBook Airs, with update 1.9 fixing a battery issue that could cause the battery to unexpectedly cease functioning.
The update can be downloaded from Apple's support site or via the Software Update tool in the Mac App Store.
Apple Releases Battery Fix SMC Firmware Update for MacBook Air [Mac Blog]