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.
Apple also addressed a rare memory issue that causes the system to randomly reboot. There is also a fix related to running an external display with Windows using Boot Camp. Just yesterday, Apple also released a SMC update for Mid 2013 MacBook Air's that helped improved battery life.
You can download the update here, or simply launch Software Update via the App Store.
[Thanks Karan B]