Your requirements could not be resolved to an installable set of packages. Problem 1 - mantle-framework/testkit[v1.1.0, ..., 1.x-dev] require php ^8.1 -> your php version (8.0.30) does not satisfy that requirement. - Root composer.json requires mantle-framework/testkit ^1.1 -> satisfiable by mantle-framework/testkit[v1.1.0, v1.1.1, v1.1.2, 1.x-dev].