The icon was boxy and emulated a small message box with three lines inside it. Some icons show their age and reflect a look that has long since passed, but the Google Messages icon didn’t seem ...

Google changed the icon design from a small message box type, with some lines inside it, to a bubble-like shape. You can essentially see two message bubbles here, one on top of the other.

With every app change, learning new icons and tools is an adjustment period. The Google Messages app is going through that now, changing up what a sent, delivered, and read message icon looks like.