Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires yoanm/symfony-jsonrpc-http-server-doc ^1.1 -> satisfiable by yoanm/symfony-jsonrpc-http-server-doc[v1.1.0, v1.1.1]. - yoanm/symfony-jsonrpc-http-server-doc[v1.1.0, ..., v1.1.1] require symfony/config ^4.4 || ^5.4 || ^6.0 -> found symfony/config[v4.4.0-BETA1, ..., 4.4.x-dev, v5.4.0-BETA1, ..., 5.4.x-dev, v6.0.0-BETA1, ..., 6.4.x-dev] but it conflicts with your root composer.json require (~7.0.0@dev). Problem 2 - Root composer.json requires matthiasnoback/symfony-config-test ^4.0 -> satisfiable by matthiasnoback/symfony-config-test[4.0.0, ..., 4.3.0]. - matthiasnoback/symfony-config-test 4.0.1 requires symfony/config ^2.7 || ^3.4 || ^4.0 -> found symfony/config[v2.7.0-BETA1, ..., 2.8.x-dev, v3.4.0-BETA1, ..., 3.4.x-dev, v4.0.0-BETA1, ..., 4.4.x-dev] but it conflicts with your root composer.json require (~7.0.0@dev). - matthiasnoback/symfony-config-test[4.1.0, ..., 4.2.1] require symfony/config ^2.7 || ^3.4 || ^4.0 || ^5.0 -> found symfony/config[v2.7.0-BETA1, ..., 2.8.x-dev, v3.4.0-BETA1, ..., 3.4.x-dev, v4.0.0-BETA1, ..., 4.4.x-dev, v5.0.0-BETA1, ..., 5.4.x-dev] but it conflicts with your root composer.json require (~7.0.0@dev). - matthiasnoback/symfony-config-test 4.3.0 requires symfony/config ^4.4 || ^5.3 || ^6.0 -> found symfony/config[v4.4.0-BETA1, ..., 4.4.x-dev, v5.3.0-BETA1, ..., 5.4.x-dev, v6.0.0-BETA1, ..., 6.4.x-dev] but it conflicts with your root composer.json require (~7.0.0@dev).