A new app icon, redrawn in Icon Composer for macOS 26. Tahoe renders it live instead of drawing one fixed image, so it follows the tinted, clear and dark icon appearances you pick in System Settings. macOS 15 gets a flattened version of the same mark.

Switching your icon from Alt or Foodie back to Default can keep showing the old one in the Dock until you relaunch OpenSolo. Letting the system render the default icon is what makes the new appearances work, and the Dock does not always redraw when the app hands control back.