You need PHP >= 5.4.0 or HHVM >= 3.2 and the
mbstring extension to use
League\Csv but the latest stable version of PHP/HHVM is recommended.
League\Csv is available on Packagist and can be installed using Composer:
composer require league/csv:^7.0
You can also use
League\Csv without using Composer by downloading the library and using any other PSR-4 compatible autoloader.