Milestone 16 was completed on 2021-06-24. It adds support for ROS 1 noetic, ROS 2 galactic, and the releases of the other ROS distros current at the end of June 2021. It also adds support for webOS OSE v2.10.0 and OpenEmbedded honister.
A new revision 23 of the OpenEmbedded Build Instructions updated for this has been published. Its change log is here. A “rich diff” of the changes made since the previous revision is here.