First up, the books will be given their own titles. The first volume - now Book III of The Last King of Osten Ard - will be called Into the Narrowdark. The second - now Book IV of the untrilogy - will retain the original title of The Navigator's Children.
The books also look like they might come out sooner than expected, with the publishers considering a spring 2022 release for the first volume and a late summer 2022 release for the second, just a few months later. Previously the publishers had been considering 22 October 2022 for the first volume and an early-to-mid-2023 release date for the second, so it appears they've shuffled things up, which is good news.
Ahead of those two volumes, a shorter novel in the same setting, Brothers of the Wind, will be published on 4 November this year.