Entering Spring means the next DLC will be the Rare Blades Pack, going by the image it seems we can expected 3 new blades, although it doesn't mean the won't be more after all NG+ gave us 7 new blades. Curiously a new NPC has been added to the game in NG+ with the recent update.
Spring 2018: New Rare Blade Pack
Summer 2018: New Challenge Mode Pack
Fall 2018: Brand-new Story Content Pack