How do we update roadmaps following releases?

E.g. the notebook roadmap describes goals for 'Next (4.1)', but 4.1 is now out. Do we discard that section, change the section header to archive it in the same document, or move it to a separate document as an archived record of what we planned to do in each release?

We are definitely planning a 4.2, and quite probably further 4.x releases, so 5.0 was not really 'next+1'. I came to add a summary of our discussion about companion files and storing volatile data like widget state, but then I realised I don't know whether that's planned for a 4.x release or not.