I upgraded from a Pi 3 to a Pi 4. I also changed from Apache to Nginx. When I tried to transfer the site from one server to the other everything broke so I had to remake it from scratch. Yes I know its not that much work (arguably less than trying to copy it but that’s not the point). Also certbot always broke the site when I tried an automatic install for the SSL certificates so I had to figure out how to set them up manualy.