Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires orchestra/workbench dev-master -> satisfiable by orchestra/workbench[dev-master]. - orchestra/workbench dev-master requires orchestra/testbench-core ^6.34.0 || ^7.27.1 || ^8.7.1 -> found orchestra/testbench-core[v6.34.0, 6.x-dev, v7.27.1, 7.x-dev, v8.7.1, 8.x-dev] but it conflicts with your root composer.json require (dev-workbench).