Set due dates for all tasks in a list
- Open Tasks.
- Tap the list containing the tasks > ••• at the bottom of the list, or Menu > Set due date for all....
- Tap the month, day, and year > Set due date.
To remove a previously assigned due date, tap No due date.
Checked against the LuneOS code and installed apps. Nobody has tried these steps by hand yet, so tell us if something differs.