Just a quick note to let you know that COPS for PHP 8.x is available from a forked repo at GitHub - mikespub-org/seblucas-cops: Calibre OPDS (and HTML) PHP Server : web-based light alternative to Calibre content server / Calibre2OPDS to serve ebooks (epub, mobi, pdf, ...) instead of the original repo GitHub - seblucas/cops: Calibre OPDS (and HTML) PHP Server : web-based light alternative to Calibre content server / Calibre2OPDS to serve ebooks (epub, mobi, pdf, ...)
General user support issues remain available at the original repo but pull requests should be against the latest source code at the forked repo.
A modified Dockerfile for the archived linuxserver/docker-cops version is available under docker/Dockerfile.linuxserver - please update to your latest standards as needed.