composer create-project symfony/website-skeleton my_project
Installing symfony/website-skeleton (v4.1.3.11)
composer require server --dev
Restricting packages listed in "symfony/symfony" to "4.1.*"
php bin/console server:run
[OK] Server listening on http://127.0.0.1:8000
composer require symfony/orm-pack
Using version ^1.0 for symfony/orm-pack
composer require symfony/maker-bundle --dev
composer require sonata-project/admin-bundle
Using version ^3.38 for sonata-project/admin-bundle
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Restricting packages listed in "symfony/symfony" to "4.1.*"
Your requirements could not be resolved to an installable set of packages.
  Problem 1
    - sonata-project/admin-bundle 3.38.3 requires symfony/class-loader ^2.8 || ^3.2 -> satisfiable by symfony/class-loader[3.4.x-dev] but these conflict with your requirements or minimum-stability.
    - sonata-project/admin-bundle 3.38.2 requires symfony/class-loader ^2.8 || ^3.2 -> satisfiable by symfony/class-loader[3.4.x-dev] but these conflict with your requirements or minimum-stability.
    - sonata-project/admin-bundle 3.38.1 requires symfony/class-loader ^2.8 || ^3.2 -> satisfiable by symfony/class-loader[3.4.x-dev] but these conflict with your requirements or minimum-stability.
    - sonata-project/admin-bundle 3.38.0 requires symfony/class-loader ^2.8 || ^3.2 -> satisfiable by symfony/class-loader[3.4.x-dev] but these conflict with your requirements or minimum-stability.
    - Installation request for sonata-project/admin-bundle ^3.38 -> satisfiable by sonata-project/admin-bundle[3.38.0, 3.38.1, 3.38.2, 3.38.3].
Installation failed, reverting ./composer.json to its original content.