PHP 8.0 reaches end of life, and what that changes

26 November, and what changes is not the code — it is that no security patch is coming for whatever is found in December.

the supported set, from 27 November 2023:

  8.1   security fixes until 2025-12
  8.2   active support until 2024-12
  8.3   active support until 2025-12

and what "end of life" does not mean:
  the code stops working          no
  the distribution stops shipping it   depends, and
                                       check yours
  a CVE will definitely appear    also no — but the
                                  decision has to assume one might

The argument that gets made every time is that nothing has actually broken, which is true and is not the point: the risk is not that a version stops working, it is that a vulnerability is disclosed and there is no patch. Distribution backports muddy this — a long-term-support distribution may patch a version upstream has retired — so the answer depends on where PHP came from, and that is worth establishing before the deadline rather than during an incident.