When guests search your Caterbook web booking engine but find there are no rooms free for a given date range, they can now be presented with a calendar showing a broad overview of availabilty.
From Settings / Property / Booking template, you can activate this feature from the Toggle availability overview tick box illustrated below.
The Limited availability threshold value determines how many free rooms at the property will result in the overview calendar showing those dates as having "A few rooms left."
Depending on whether you have 5 rooms or 50 your definition of what constitutes "Limited availability is going to be different, but a rule of thumb might be 1 out of every 5 rooms for smaller properties, 1 in 10 for those with more rooms.