Fatal error: Uncaught Error: Interface "Composer\Plugin\PluginInterface" not found in /srv/disk3/2724534/www/redgraveresearch.com/concrete/vendor/composer/package-versions-deprecated/src/PackageVersions/Installer.php:34 Stack trace: #0 {main} thrown in /srv/disk3/2724534/www/redgraveresearch.com/concrete/vendor/composer/package-versions-deprecated/src/PackageVersions/Installer.php on line 34