Fatal error: Uncaught Error: Interface 'Psr\Http\Server\RequestHandlerInterface' not found in /home/gcpsxdwf/public_html/forum.oandplibrary.org/vendor/flarum/core/src/Install/Controller/InstallController.php:28 Stack trace: #0 {main} thrown in /home/gcpsxdwf/public_html/forum.oandplibrary.org/vendor/flarum/core/src/Install/Controller/InstallController.php on line 28