>>So the question is why we have to modify also (a) to make (c) happy?
>I still do not understand what the problem is. meta-clang does have a dunfell branch, that sets LAYERSERIES_COMPAT accordingly, why are you not using that?
Please assume that we can't, if this would make it possible to finally answer my aforementioned question.
Sorry, not possible. If dunfell branch doesn't do what you need it to, the correct solution is to send patches for the branch, or backport the needed changes into your internal copy of that layer. But certainly not to start mixing layer revisions from different releases and demand that this must be supported and easy.
Alex