I am trying to upgrade the forum but discovered that this seems to be impossible.
I am currently on 4.7.1 which does not support PHP 8.0 and the automated upgrade path only works if PHP 8.0 is installed.
So, I am not in a situation where there is no possible path forward for the upgrade. Here is the error message when switching to a newer PHP.
The forum does not run any third-party extensions or plugins.
What's the solution?