Every Mac in existence requires Firmware to run. Most Mac users don’t give a thought to what Firmware their Mac is running, if it is up to date or not. It is important to keep your Firmware current for an optimal Mac experience. Here is a typical definition of Firmware:
Firmware provides the instructions for the hardware on your Mac to run correctly. The instructions control many low-level functions that affect the power, thermal and sleep management features. Updates to the firmware can also add additional features to your computer and improve the reliability of your hardware.
The whole concept of Firmware is quite technical. This article describes the basics of Firmware. It is technical so it might not be for everyone. However, at the end of the article there are links to determine what version of Firmware your Mac should be running. It is worth checking that out.