FOSUserBundle registration form in Symfony 4.3

Question

I'm trying to setup my FOSUserBundle 2.0 for Symfony 4.3 following this documentation: https://symfony.com/doc/2.1/bundles/FOSUserBundle/index.html

I created a new member class that extends FOSUser like in the documentation:

use FOS\UserBundle\Model\User as BaseUser;
use Doctrine\ORM\Mapping as ORM;

class NewMember extends BaseUser
    {
        /**
         * @var int
         *
         * @ORM\Id
         * @ORM\Column(name="id", type="integer")
         * @ORM\GeneratedValue(strategy="IDENTITY")
         */
        protected $id;

        /**
         * @var string
         *
         * @ORM\Column(name="displayName", type="string", length=50, nullable=true)
         */
        protected $displayName;

I configure user_class in fos_user.yaml:

# config/packages/fos_user.yaml
fos_user:
    db_driver: orm # other valid values are 'mongodb' and 'couchdb'
    firewall_name: main
    user_class: App\Entity\Main\NewMember
    from_email:
        address: "test@domain.com"
        sender_name: "test@domain.com"

I use the fos_user.registration.form.factory but my registration form always get the same fields, no matter what I do:

Email
Username
Password
Repeat password

Any help is appreciated. Thank you in advance.