Looks like the final linux patches were submitted last week.
https://rvspace.org/en/project/JH7110_Upstream_Plan
Once the last few are accepted does that mean distros like armbian can finally let us use something newer than 5.15 such as maybe 6.7 onwards?
One tiny fly in the ointment is that the 6.6 mainline release 2023-10-30 will with a very high probability become the next Long Term Supported linux kernel and then it will be another year before the next LTS kernel is selected. The reason is that it usually takes 9-10 weeks for the next new mainline kernel to be ready, so that would be early 2024 before 6.7 would be a mainline kernel and historically the LTS kernels are announced between October and December.
Earlier versions of those patches have been submitted quite for a while now. But submitted doesn’t mean accepted. There is ongoing discussion about those patches here: https://lore.kernel.org/lkml/?q=JH7110
Kind regards!
Your assumption was right: Linux 6.6 Formally Becomes This Year's LTS Kernel - Phoronix
For next year, my crystal ball told me that 6.11 will be the LTS.
“Full upstream” means everything besides kernel DRM driver for the GPU. So, it’s ok for server use but not for anything graphical.