Currently in the Date/Time custom field options there is no way to choose a minimum amount of days out. For example if I have a specific request type where we do not want users to submit a ticket for an event setup happening in less than 48 hours when they load the date picker they are unable to pick today or the next two business days. This would be useful as it ensures techs have enough time to get things in order for a setup or forces users to call in if they have an emergency need.
