This feature is only available for tasks in a List, Blank Journal, and Project.
Open the Journal List and tap the 3 dots icon at the bottom right corner, then tap "auto move unfinished tasks”
You can also move all the unfinished tasks to another day by tapping the relative button just above the previous one.
The tasks are moved when the day changes, this automation affects only the current day's unfinished/not-done/unchecked tasks (to manually move unfinished tasks to a different day at once you can use the “Move unfinished…” buttons in the three dots menu).
Tasks are not moved exactly at midnight, the automations are set to be completed within 3AM.