With our last update 3.4.5 you can find new and improved capacity/inventory management system in Admin panel. It has been moved from General section to it’s own section as we want to embrace the WooCommerce stock management extensions and improve the functionality. You can now determine SKU and quantity of available places per slot the same way you would manage stock for simple products.
The inventory section allows you to manage stock for the appointable product individually and allows you to set minimum and maximum available places per order. Setting minimum and maximum quantity per order is useful, when you are offering multiple places per each available slot and you want to force customers to book min and max number of slots per order. In upcoming releases we will also add option to allow backorders, so your customers will get in line (will require your approval) for slots that are not available.