Could be a while. Our efforts with the RK 4.4 kernel codebase have been a stop-gap until VPU support for the mainline kernel was available and the changes to add this now been submitted so we've started the lengthy process of rebasing against Linux 4.19 - which means no more real-world effort against the 4.4 codebase.
NB: Next 9.0 Alpha will come out with changes to Kodi but nothing much more. We have no plans to release Rockchip Beta or full release LE 9.0 images - Rockchip will remain in an Alpha state until at least LE 9.2.