In successive versions of the Chronology of Cities in Flight:
John Amalfi died in a hunting accident in 4004;
the universe ended in 4004;
the universe ended in 4104.
That last event and date remained in the text but the Chronology was left out of the omnibus edition.
The hunting accident, appearing in the Chronology but not in any text, was just meant as a reminder that even people with antiagathics will eventually die by accident or violence. When Blish did come to write an ending, he had his characters living until the end of the universe which, however, was brought unexpectedly close to the present for narrative purposes.