Problème d'installation de Sonata

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  Problem 1
    - sonata-project/page-bundle 2.3.9 requires sonata-project/seo-bundle ~1.1 -> no matching package found.
    - sonata-project/page-bundle 2.3.8 requires sonata-project/seo-bundle ~1.1 -> no matching package found.
    - sonata-project/page-bundle 2.3.7 requires sonata-project/seo-bundle ~1.1 -> no matching package found.
    - sonata-project/page-bundle 2.3.6 requires sonata-project/seo-bundle ~1.1 -> no matching package found.
    - sonata-project/page-bundle 2.3.5 requires sonata-project/seo-bundle ~1.1 -> no matching package found.
    - sonata-project/page-bundle 2.3.4 requires symfony/symfony >=2.2,<2.4-dev -> no matching package found.
    - sonata-project/page-bundle 2.3.3 requires symfony/symfony >=2.2,<2.4-dev -> no matching package found.
    - sonata-project/page-bundle 2.3.2 requires symfony/symfony >=2.2,<2.4-dev -> no matching package found.
    - sonata-project/page-bundle 2.3.1 requires symfony/symfony >=2.2,<2.4-dev -> no matching package found.
    - sonata-project/page-bundle 2.3.0 requires symfony/symfony >=2.2,<2.4-dev -> no matching package found.
    - Installation request for sonata-project/page-bundle ^2.3 -> satisfiable by sonata-project/page-bundle[2.3.0, 2.3.1, 2.3.2, 2.3.3, 2.3.4, 2.3.5, 2.3.6, 2.3.7, 2.3.8, 2.3.9].

Potential causes:
 - A typo in the package name
 - The package is not available in a stable-enough version according to your minimum-stability setting
   see <https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion> for more details.

Read <https://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.

{
    "name": "root/ms",
    "license": "proprietary",
    "type": "project",
    "autoload": {
        "psr-4": {
            "": "src/"
        }
    },
    "require": {
        "php": ">=5.3.9",
        "symfony/symfony": "2.7.*",
        "doctrine/orm": "^2.4.8",
        "doctrine/doctrine-bundle": "~1.4",
        "symfony/assetic-bundle": "~2.3",
        "symfony/swiftmailer-bundle": "~2.3",
        "symfony/monolog-bundle": "~2.4",
        "sensio/distribution-bundle": "~4.0",
        "sensio/framework-extra-bundle": "^3.0.2",
        "incenteev/composer-parameter-handler": "~2.0",
        "sensio/generator-bundle": "^2.5",
        "doctrine/doctrine-fixtures-bundle": "^2.3",
        "twig/extensions": "^1.3",
        "gedmo/doctrine-extensions": "^2.4",
        "nervo/yuicompressor": "^2.4",
        "friendsofsymfony/user-bundle": "^1.3",
        "sonata-project/core-bundle": "^2.3",
        "sonata-project/admin-bundle": "^2.3",
        "sonata-project/user-bundle": "^2.2",
        "sonata-project/doctrine-orm-admin-bundle": "^2.3",
        "sonata-project/easy-extends-bundle": "^2.1",
        "sonata-project/cache-bundle": "^2.2",
        "sonata-project/seo-bundle": "^2.0",
        "sonata-project/notification-bundle": "^2.3"
    },
    "require-dev": {
    },
    "scripts": {
        "post-install-cmd": [
            "Incenteev\\ParameterHandler\\ScriptHandler::buildParameters",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::prepareDeploymentTarget"
        ],
        "post-update-cmd": [
            "Incenteev\\ParameterHandler\\ScriptHandler::buildParameters",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::prepareDeploymentTarget"
        ]
    },
    "config": {
        "bin-dir": "bin"
    },
    "extra": {
        "symfony-app-dir": "app",
        "symfony-web-dir": "web",
        "symfony-assets-install": "relative",
        "incenteev-parameters": {
            "file": "app/config/parameters.yml"
        }
    }
}