I don't know the official process, but as a human that sometimes reads and implements IETF RFCs, I'd appreciate updates to the original doc rather than replacing it with something brand new. Probably with some dated version history.

Otherwise I might go to consult my favorite RFC and not even know its been superseded. And if it has been superseded with a brand new doc, now I have to start from scratch again instead of reading the diff or patch notes to figure out what needs updating.

And if we must supersede, I humbly request a warning be put at the top, linking the new standard.

At one point I could have sworn they were sticking obsoletion notices in the header, but now I can only find them in the right side-bar:

https://datatracker.ietf.org/doc/html/rfc5245

I agree, that it would be much more helpful if made obvious in the document itself.

It's not obvious that "updated by" notices are treated in any more of a helpful manner than "obsoletes"