The section "General Notes Regarding Future FreeBSD Releases" must correspond to current state. The removed version of the section was copies from 14.3R relnotes and obsolete since 15.R release date.
When 14.0R was released, its "Future release" section was used for later 13.X releases (and so on in the past).
The 15.0R relnotes were released without "Future release" section, and this information need to be updated and published as soon as it will be ready.
As agreed earlier, I publish it to make visible for comments in the tree.