# Build Options ## Selecting a Symfony Skeleton By default, Symfony Docker will install the minimalist skeleton. To install the ["website skeleton"](https://symfony.com/doc/current/setup.html#creating-symfony-applications), use the following command: SKELETON=symfony/website-skeleton docker-compose up --build ## Selecting a Specific Symfony Version Use the `SYMFONY_VERSION` environment variable to select a specific Symfony version. For instance, use the following command to install Symfony 4.4: SYMFONY_VERSION=4.4.* docker-compose up --build ## Installing Development Versions of Symfony To install a non-stable version of Symfony, use the `STABILITY` environment variable during the build. The value must be [a valid Composer stability option](https://getcomposer.org/doc/04-schema.md#minimum-stability)) . For instance, use the following command to use the `master` branch of Symfony: STABILITY=dev docker-compose up --build ## Customizing the Server Name Use the `SERVER_NAME` environment variable to define your custom server name(s). SERVER_NAME="symfony.wip, caddy:80" docker-compose up --build If you use Mercure, keep `caddy:80` in the list to allow the PHP container to request the caddy service. ## Using custom HTTP ports Use the environment variables `HTTP_PORT`, `HTTPS_PORT` and/or `HTTP3_PORT` to adjust the ports to your needs, e.g. HTTP_PORT=8000 HTTPS_PORT=4443 HTTP3_PORT=4443 docker-compose up --build to access your appplication on [https://localhost:4443](https://localhost:4443).