Your requirements could not be resolved to an installable set of packages. Problem 1 - yiisoft/view[6.0.0, 7.0.0, ..., 7.0.1, 8.0.0] require psr/event-dispatcher-implementation 1.0.0 -> could not be found in any version, but the following packages provide it: - symfony/event-dispatcher Provides tools that allow your application components to communicate with each other by dispatching - league/event Event package - symfony/symfony The Symfony PHP framework - phpfastcache/phpfastcache PHP Abstract Cache Class - Reduce your database call using cache system. Phpfastcache handles a lot - yiisoft/event-dispatcher Yii Event Dispatcher - crell/tukio A robust, stand-alone PSR-14 event dispatcher implementation. - carlosas/simple-event-dispatcher Simple PSR-14 Event Dispatcher - phpactor/phly-event-dispatcher Experimental event dispatcher for PSR-14 - phly/phly-event-dispatcher Experimental event dispatcher for PSR-14 - yiisoft/psr-dummy-provider PSR Dummy Provider - circli/event-dispatcher PSR-14 event dispatcher implementation. - phoole/event Slim, powerful and full compatible PSR-14 event manager library for PHP - windwalker/event Windwalker Event package - berlioz/core Berlioz Framework Core - berlioz/cli-core Berlioz Framework CLI Core - ngsoft/tools A set of reusable tools used on my projects. - windwalker/framework The next generation PHP framework. - berlioz/event-manager PHP event manager/dispatcher, respecting PSR-14 (Event Dispatcher) standard. - bytic/event-dispatcher ByTIC Events package. - neat/event Neat Event components ... and 34 more. Consider requiring one of these to satisfy the psr/event-dispatcher-implementation requirement. - yiisoft/view-twig 2.1.0 requires yiisoft/view ^6.0|^7.0|^8.0 -> satisfiable by yiisoft/view[6.0.0, 7.0.0, 7.0.1, 8.0.0]. - Root composer.json requires yiisoft/view-twig ^2.1 -> satisfiable by yiisoft/view-twig[2.1.0]. Potential causes: - A typo in the package name - The package is not available in a stable-enough version according to your minimum-stability setting see <https://getcomposer.org/doc/04-schema.md#minimum-stability> for more details. - It's a private package and you forgot to add a custom repository to find it Read <https://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.