Composer update error

If you installed the new composer on php version 7.1, this will show an error like this : Class UpdateHelper\ComposerPlugin contains 2 abstract methods and must therefore be declared abstract or implement the remaining methods (Composer\Plugin\PluginInterface::deactivate, Composer\Plugin\PluginInterface::uninstall) in /var/www/vhosts/example.com/vendor/kylekatarnls/update-helper/src/UpdateHelper/ComposerPlugin.php on line 11 Here is a solution to this issue

You need to remove/delete the following folder from vendor directory :

vendor/kylekatarnls



Then run the following command :

composer update --prefer-source



Then this command : 

composer dump-autoload

Mohammed Anwar

Experienced technical lead PHP, MySQL and Laravel Developer for 15+ years, with proven ability to develop and create high-quality and optimized web applications. Great ability to build and optimize database design, schema and queries. Versed programing trainer and instructor delivering web courses and helping others to get into the field in a timely manner. Fast and eager learner for new technologies .