Automatic due dates allow you to specify a task due date that is relative to either the trip start date or the trip end date.
To add an automatic due date to a task assigned to a trip, open the task that you would like to add the automatic date to. Under the due date, click on the Automatic button.
Note: this feature only applies to tasks that have an assigned trip.
From there you can then specify the number of days the task needs to be completed by and whether it needs to occur before or after the trip start or end date. Once you have specified the number of days the task needs to be completed by(either before or after the start date), the calculated due date will automatically appear beneath the Fixed/Automatic toggle.
Note: in order for an exact due date to be calculated, a trip start /end date must be added to the trip.
Any tasks with an automatic due date will then show the green calendar icon next to the date.