From April to June they promise difficulty, pets and boss rematches

Three weeks after Pywel opened, Pearl Abyss gathered feedback and sketched updates for April through June. Boss rematches, siege replays and three difficulty levels are coming. Damiana and Ungka get new abilities, weapons on the back can be hidden, and costumes that could not be worn before will be added.

Separate stores for resources, food, clothes and collections. New pets and mounts with armor. Interface, key rebinding and farther vistas, which will make the patches heavier. A free soundtrack DLC will come to Steam. The plans can change. The Steam note.

This is a roadmap, not a list of patches that have already shipped.