This is the overwriting of an existing article The newsreader generates a special article with a control message in the header which tells the newsserver to overwrite the existing article with this one
If something is superseded by something newer, it is replaced because it has become old-fashioned or unacceptable. Hand tools are relics of the past that have now been superseded by the machine. if a new idea, product, or method supersedes another one, it becomes used instead because it is more modern or effective = replace (superseder , from supersedere , from sedere )
take the place or move into the position of; "Smith replaced Miller as CEO after Miller left"; "the computer has supplanted the slide rule"; "Mary replaced Susan as the team's captain and the highest-ranked player in the school"