When does Wings of Fire return?

Wings of Fire is a series of high fantasy novels about dragons. The series has sold over 27 million copies and has been on the New York Times bestseller list for over 200 weeks. The main series consists of three arcs (soon to be four) of five books apiece, which focus on young dragons. Each book centers on its own protagonist, whose story is told through a third person limited perspective. Fifteen books in the main series have been released, as well as four novellas (known as Winglets), two extended-length standalone novels and multiple companion books.