MacBook Air SMC Update v1.8 MacBook Air SMC Update v1.8
This update addresses a rare issue on some Apple notebooks where a battery that has accumulated more than 1000 charge cycles may unexpectedly shut down or stop functioning.
https://support.apple.com/kb/DL1688

I have an MacBook Air (13-inch, Mid 2011) running El Capitan 10.11.6 (15G22010).
I have ignored this update for a long time because my battery, though not in good health, has 332 charge cycles, nowhere near 1000 charge cycles.
Do I need to apply this update at all? Should I apply it anyway?
If I install High Sierra 10.13, do I need to apply it before upgrading? Or will the OS upgrade make the SMC update obsolete?
Do I need to apply this update at all?

Is your Mac exhibiting any of the symptoms described?  If not, then no, you don't need to apply it.

Should I apply it anyway?

There are two schools of thought concerning this, so you're not going to get a concrete answer.  They are:

All updates should be applied to keep the machine up to date whether it needs the update or not.

Updates should only be applied to fix/address a particular problem.  With this line of thinking, you can refer to the old adage &quot;If it ain't broke, then don't fix it.&quot;


What should you do?
Move forward with installing High Sierra.  If the problem manifests, then you want to install the firmware.  But even after you install High Sierra, you have to do a &quot;gut check&quot; of sorts.

Do you feel more comfortable with a system with all the latest updates?  Then do the update
Are you OK with not having the latest firmware especially since there isn't a problem to fix?  Don't apply it, keep calm and carry on.

The thing is, it comes down to you and how secure you feel about it.