Apple has made a very subtle design change to the M4 MacBook Air to make it easier to spot when side by side with the M3 and M2 models. As iCulture.nl points out, the M4MacBook Air has a design detail that's easy to spot but isn't immediately obvious.

**Changes to mute key icon**

This change is reflected in the volume keys of the built-in keyboard. The M2 and M3 MacBook Air's mute key uses a simple speaker outline icon, while the M4 MacBook Air uses a slashed speaker outline icon to indicate mute.

**Design Logic**

The previous mute key icon made sense when compared to the volume down and volume up keys, but the new mute key icon is intuitive to understand even without comparing it to other volume key icons.

In addition, this icon is consistent with the mute icon used by Apple in the software, and Apple also uses the same mute key icon on the Magic Keyboard of the new M3 iPad Air.

Of course, the bigger design change is to replace the space gray with a new sky blue, which is currently exclusive to the M4 MacBook Air.