Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires contao/manager-bundle 2.8 (exact version match: 2.8, 2.8.0 or 2.8.0.0), found contao/manager-bundle[4.3.0, ..., 4.13.x-dev, 5.0.0-RC1, ..., 5.x-dev] but it does not match the constraint. Problem 2 - contao-community-alliance/dc-general-contao-frontend dev-feature/2.4.0 requires contao-community-alliance/dc-general ^2.4@dev -> found contao-community-alliance/dc-general[dev-release/2.4.0, 2.4.x-dev (alias of dev-release/2.4.0)] but it does not match your minimum-stability. - contao-community-alliance/dc-general-contao-frontend 2.4.x-dev is an alias of contao-community-alliance/dc-general-contao-frontend dev-feature/2.4.0 and thus requires it to be installed too. - Root composer.json requires contao-community-alliance/dc-general-contao-frontend ^2.4@dev -> satisfiable by contao-community-alliance/dc-general-contao-frontend[2.4.x-dev (alias of dev-feature/2.4.0)].

Process completed with exit code 2.