Composer require sonata-project/core-bundle in Symfony 3.4

Question

I'd like to add sonata-project/user-bundle to Symfony 3.4 project but i received the following error message, BTW, i already installed "sonata-project/doctrine-orm-admin-bundle" :

composer require "sonata-project/user-bundle"
-------------------------------

Using version ^4.7 for sonata-project/user-bundle
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - sonata-project/user-bundle 4.7.0 conflicts with sonata-project/core-bundle[3.17.2].
    - sonata-project/user-bundle 4.7.0 conflicts with sonata-project/core-bundle[3.17.2].
    - sonata-project/user-bundle 4.7.0 conflicts with sonata-project/core-bundle[3.17.2].
    - Installation request for sonata-project/user-bundle ^4.7 -> satisfiable by sonata-project/user-bundle[4.7.0].
    - Installation request for sonata-project/core-bundle (locked at 3.17.2) -> satisfiable by sonata-project/core-bundle[3.17.2].

For information, this the content of the composer.json file :

    "require": {
        "php": ">=5.5.9",
        "doctrine/doctrine-bundle": "^1.6",
        "doctrine/orm": "^2.5",
        "incenteev/composer-parameter-handler": "^2.0",
        "sensio/distribution-bundle": "^5.0.19",
        "sensio/framework-extra-bundle": "^5.0.0",
        "sonata-project/doctrine-orm-admin-bundle": "^3.8",
        "symfony/monolog-bundle": "^3.1.0",
        "symfony/polyfill-apcu": "^1.0",
        "symfony/swiftmailer-bundle": "^2.6.4",
        "symfony/symfony": "3.4.*",
        "twig/twig": "^1.0||^2.0"
    }

   

So what can i do please ?