upgrade composer

C++
composer self-update
composer self-updatephp composer.phar self-updatecomposer install --ignore-platform-reqsphp composer.phar 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
Source

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