Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires pimcore/generic-data-index-bundle 2.x-dev -> satisfiable by pimcore/generic-data-index-bundle[2.x-dev]. - pimcore/generic-data-index-bundle 2.x-dev requires pimcore/pimcore ^v11.5 -> found pimcore/pimcore[v11.5.0-RC1, ..., 11.x-dev] but it conflicts with your root composer.json require (^12.x-dev). Problem 2 - Root composer.json requires pimcore/admin-ui-classic-bundle ^v1.3 -> satisfiable by pimcore/admin-ui-classic-bundle[v1.3.0-RC1, ..., 1.x-dev]. - pimcore/admin-ui-classic-bundle[v1.3.0-RC1, ..., v1.3.0] require pimcore/pimcore ^11.1 -> found pimcore/pimcore[v11.1.0-RC1, ..., 11.x-dev] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle v1.3.1 requires pimcore/pimcore ^11.1.3 -> found pimcore/pimcore[v11.1.3, ..., 11.x-dev] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle[v1.3.2, ..., v1.3.5] require pimcore/pimcore ^11.1.4 -> found pimcore/pimcore[v11.1.4, ..., 11.x-dev] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle[1.4.0, ..., v1.4.4] require pimcore/pimcore ^11.2.0 -> found pimcore/pimcore[v11.2.0, ..., 11.x-dev] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle v1.4.5 requires pimcore/pimcore ~11.2.0 -> found pimcore/pimcore[v11.2.0, ..., v11.2.7] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle v1.5.0-RC1 requires pimcore/pimcore 11.3.0-RC1 -> found pimcore/pimcore[v11.3.0-RC1] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle v1.5.0-RC2 requires pimcore/pimcore ^11.3.0 -> found pimcore/pimcore[v11.3.0-RC1, ..., 11.x-dev] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle[v1.5.0, ..., v1.5.2] require pimcore/pimcore ~11.3.0 -> found pimcore/pimcore[v11.3.0-RC1, ..., v11.3.3] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle[v1.5.3, ..., v1.5.5] require pimcore/pimcore ~11.3.1 -> found pimcore/pimcore[v11.3.1, v11.3.2, v11.3.3] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle[v1.6.0-RC1, ..., v1.6.6] require pimcore/pimcore ^11.3.1 -> found pimcore/pimcore[v11.3.1, ..., 11.x-dev] but it conflicts with your root composer.json require (^12.x-dev). - pimcore/admin-ui-classic-bundle[v1.7.0, ..., 1.x-dev] require pimcore/pimcore ^11.5.0 -> found pimcore/pimcore[v11.5.0-RC1, ..., 11.x-dev] but it conflicts with your root composer.json require (^12.x-dev).