composer self-update// Upgrade Version composer self-update // or composer self-update --2 // Downgrade Version composer self-update --1composer self-update composer self-updatesudo composer self-updatesudo -u nginx php composer.phar update php7.3 -f /usr/local/bin/composer updatecomposer self-update To update composer command just find location of composer.phar and update as: where composer #Retrieves you location of your composer.phar cd path_to_composer.phar #Move to directory with composer.phar php composer.phar self-update #Update your composer