Downloading MacBook Air SMC Update 2.0 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. The program lies within System Tools, more precisely System Optimization. This free Mac app is an intellectual property of Apple Inc. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software.
From the developer:
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.
The version change is reflected in the System Profiler available on the Mac.
You may want to check out more software for Mac, such as MacBook Pro SMC Firmware Update, which might be related to MacBook Air SMC Update.