ClassicPress 1.5.0 was released a few days ago with support for PHP 8. And this solves a lot of problems I had on this blog in the last few month: On the homepage was the title „Archive“ visible, which should not be visible; and on my archive page nothing was shown at all—except for the title; and all I‘ve got was mysterious error messages in the logs … Guess I should have better looked at the requirements (which are now, btw, a bit outdated), than I would have seen that I was using the wrong PHP version. Lesson learned.
So now I can start tinkering on this blog again and not try to hunt this weird behavior of ClassicPress.