When setting a due date or payment schedule on an Invoice, the client isn't automatically notified of upcoming payments due.

You can send a client an automated email using Workflows. Keep in mind that it is not linked to the Invoice, so we recommend adding the wording of 'if you have recently paid, please disregard this message'.

The alternative is to set up a reminder task for your team (also possible via Workflows) to check on this X days before the Booking date to follow up with the guest if it hasn't been paid. You're also able to keep track of them internally using the Scheduled Payments Report.