From now, pets are displayed as Display Entity. If you use Geyser, change pets_format in config to "LEGACY"
(Geyser not supports Display Entities)
Example configuration for pets appearance:
Code (Text):
appearance:
scale: 1.2
displayname:
background_color: "BLACK"
background_opacity: 50
Available background colors:
- BLACK
- WHITE
- RED
- GREEN
- BLUE
- YELLOW
- ORANGE
- PURPLE
- GRAY
Background opacity value is percent and need to be i range 0-100 (%)