Some new info seems to be available to EAF which suggests LH will take up to 21(?) B789s, 9 of which are white tails to be delivered in 2021 and 2022 using the semi-new Business Class.
B789s from 2023 will then get the new Business Class.
This would somewhat fit in with my theory that the 789s will be split between LH and OS as LH can replace their aging 343s and 333s in FRA with them and OS will get them to replace their remaining 767s.