I have a working TYPO3 11.5.36 with PHP 7.4.21 (non-composer-install). If I move to PHP 8.1.9 the site gets broken, and it's weird because if I delete all cachefiles in filesystem (typo3temp/var/cache) I can
- access a page, e.g. the backend login form ONCE =>
- cache files are written again =>
- after that the next request shows a ERR_CONNECTION_RESET (because the Apache child dies/restarts, too) =>
- backend/frontend is not working any more
- no useful log entries
If I disable ~10 system extensions in PackageStates.php like tstemplate, sys_note, setup, ... I can access the site, but have all the backend stuff missing of course. If I enable one of this system extensions again, the site breaks again. BTW: Installtool is accessible all the time, but flushing the cache throws an error then, too.
Any suggestions on this behaviour or did I miss something with PHP8?