Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires laravel/tinker dev-develop, found laravel/tinker[dev-master, v1.0.0, ..., 1.x-dev, v2.0.0, ..., 2.x-dev, 3.x-dev (alias of dev-master)] but it does not match the constraint. Problem 2 - Root composer.json requires orchestra/testbench 10.x-dev -> satisfiable by orchestra/testbench[10.x-dev]. - orchestra/testbench 10.x-dev requires orchestra/workbench ^10.0 -> satisfiable by orchestra/workbench[10.x-dev]. - orchestra/workbench 10.x-dev requires laravel/tinker ^2.10.1 -> found laravel/tinker[v2.10.1, 2.x-dev] but it conflicts with your root composer.json require (dev-develop).