In Settings -> Organisation Configuration, if you choose Stripe as your Gateway, the Auto Charge/Auto Refund option becomes available.
Stripe does not keep deposits for more than a week and releases them after 7 days automatically. Thus, for bookings more than a week old, you need to renew the deposit after 7 days manually (You have to void the deposit and ask the guests to do the process again).
However, if you tick the Auto Charge/Auto Refund box, the system considers Stripe deposits as actual payments. That is when guests authorise the deposit, the amount is transferred to your account and after guests’ departure, if you do not want to Capture some or all of it, it will be automatically refunded to them based on your setting in Organisation Configuration.
Please note that £3.00 per deposit transaction will be deducted from your account.