There are four color type indications:
Available
This VBOS device is available for booking.
Partly available
This VBOS device is currently available but has been booked for a time later today. Check the app for more details.
Occupied according to the sensor
This VBOS device has not been booked, but the sensor has registered that the desk or room is in use.
Booked by a user
This VBOS device is not available for booking at this time.