What is the difference between archiving and deleting?

Done is a checkmark: the entry stays in its topic, disappears from "Unread" and appears in the Done filter. In Settings you can have done entries archived automatically after a while (immediately, 1 hour up to 24 hours).

Archiving tidies up without losing anything. Archived entries sit in the Archive filter, stay searchable and come back with one swipe. You can also archive a whole topic; all its entries move with it. If you archive a shared topic, sharing ends: the members lose access, even if you restore it later. To share it again after restoring, share it anew; the old invite link no longer works.

When you restore an entry from an archived topic, 4later asks whether to restore the whole topic (with all its entries; a shared topic comes back private) or only this entry: the topic then stays archived and the entry moves, active, into the 4later topic, together with its reminder.

Deleting puts the entry into the Bin. From there you can restore it. In Settings you set when the bin empties itself: never, after 1 day, 1 week, 1 month, 6 months or 1 year. Until then the entry still counts towards your storage.

Undo: Right after archiving or deleting you can shake the device briefly, and 4later offers to take the action back.

If you archive or delete the last entry of a topic, 4later asks whether the now empty topic should be archived along with it.