Apple released MacBook Air EFI Firmware Update 2.8 for mid-2013 and 2014 models Tuesday. The update addresses sleep and memory issues.
Mid-2013 MacBook Air Models
Apple's patch notes in full:
This update is recommended for MacBook Air (mid 2013 and early 2014) models.
This update improves reliability when waking from sleep and when booting while certain USB and Thunderbolt devices are connected.
This update also addresses a rare memory issue that may cause the system to randomly reboot, and an issue where the system may not properly sleep the built-in display when an external display is connected while running Windows using Boot Camp.
The update is a 4.8MB download from Apple's support site.