Pour avoir php8.4 (minimum synfony)

sudo LC_ALL=C.UTF-8 add-apt-repository ppa:ondrej/php # Press enter to confirm.
sudo apt-get update
sudo apt-get -y install lsb-release ca-certificates curl apt-transport-https
sudo curl -sSLo /tmp/debsuryorg-archive-keyring.deb https://packages.sury.org/debsuryorg-archive-keyring.deb
sudo dpkg -i /tmp/debsuryorg-archive-keyring.deb
sudo sh -c 'echo "deb [arch=amd64 signed-by=/usr/share/keyrings/deb.sury.org-php.gpg] https://packages.sury.org/php/ $(lsb_release -sc) main" > /etc/apt/sources.list.d/php.list'
sudo apt-get update

Sur linux, il faut installer les différent modules séparément

sudo apt install php8.4 php8.4-xml php8.4-intl php8.4-mbstring php8.4-curl php8.4-sqlite3

symfony check:requirements

symfony new my_project_directory --version="8.0.*" --webapp

symfony server:start