Laravel needs latest version of laravel to install and update dependencies in your laravel projects. To support this, use the below commands to upgrade the composor version in Ubuntu.
To Update your OS dependencies
sudo apt-get update
To install the latest version of composer
sudo curl -s https://getcomposer.org/installer | php sudo mv composer.phar /usr/local/bin/composer
That’s It. To validate composor , type be command
composer -v