How does the Supersedes: header work?
Commonly used for periodic postings and other information updates, the Supersedes: header replaces an old message with a new one. t is especially useful for FAQ maintainers, who use it to replace old versions of the FAQ with more up-to-date ones – this FAQ, for example, uses it. To replace the message <4b6uce$ou7@vixen.cso.uiuc.