When the Parrot Skycontroller 4 is powered on, its LED status indicator gives you an instant visual indication:
Flashing green:
Skycontroller 4 update in progress
Alternating light blue and dark blue:
Connecting to ANAFI USA
Flashing light blue:
No drone configured or wrong WPA key
Steady dark blue:
Connected to ANAFI USA
Alternating purple and dark blue:
RTH in progress
Alternating red and any other color:
Low battery alert (ANAFI USA, Skycontroller 4, or both) or RTH alert