I'm getting this when i'm trying to install an extension.

Warning: Unsupported declare 'strict_types' in /home/SITE_NAME/public_html/vendor/magento/inventory-composer-installer/src/Plugin.php on line 6

Parse error: syntax error, unexpected ':', expecting ';' or '{' in /home/SITE_NAME/public_html/vendor/magento/inventory-composer-installer/src/Plugin.php on line 55

I have : CentOS Linux release 7.5.1804 (Core); PHP 7.2 (via cPanel) ; Latest magento 2.3.3 CE

php -v PHP 5.6.40 (cli) (built: Oct 29 2019 08:07:50)

Need Some Help


2 Answers 2


either you could update your php to 7.X version or downgrade your ProxyManager. this will fix your problem.


In my issue I have resolved it like this php /path_to_composer/composer.phar install So try to find right version of php and run composer by php

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