Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires larastan/larastan ^2.7|^3.0 -> satisfiable by larastan/larastan[v2.7.0, ..., 2.x-dev, v3.0.0, ..., 3.x-dev]. - Root composer.json requires laravel/framework 12.* -> satisfiable by laravel/framework[12.x-dev (alias of dev-master)]. - illuminate/support[v9.51.0, ..., 9.x-dev] require illuminate/contracts ^9.0 -> found illuminate/contracts[v9.0.0-beta.1, ..., 9.x-dev] but it conflicts with your root composer.json require (^10.0|^11.0|^12.0). - larastan/larastan v2.7.0 requires illuminate/support ^9.52.16 || ^10.28.0 -> satisfiable by illuminate/support[v9.52.16, 9.x-dev, v10.28.0, ..., 10.x-dev]. - larastan/larastan[v2.9.9, ..., 2.x-dev] require illuminate/support ^9.52.16 || ^10.28.0 || ^11.16 -> satisfiable by illuminate/support[v9.52.16, 9.x-dev, v10.28.0, ..., 10.x-dev, v11.16.0, ..., 11.x-dev]. - larastan/larastan[v2.8.0, ..., v2.9.8] require illuminate/support ^9.52.16 || ^10.28.0 || ^11.0 -> satisfiable by illuminate/support[v9.52.16, 9.x-dev, v10.28.0, ..., 10.x-dev, v11.0.0, ..., 11.x-dev]. - larastan/larastan[v3.0.0, ..., 3.x-dev] require illuminate/support ^11.15.0 -> satisfiable by illuminate/support[v11.15.0, ..., 11.x-dev]. - Only one of these can be installed: illuminate/support[dev-master, v6.0.0, ..., 6.x-dev, v7.0.0, ..., 7.x-dev, v8.0.0, ..., 8.x-dev, v9.0.0-beta.1, ..., 9.x-dev, v10.0.0, ..., 10.x-dev, v11.0.0, ..., 11.x-dev, 12.x-dev], laravel/framework[dev-master]. laravel/framework replaces illuminate/support and thus cannot coexist with it. - laravel/framework 12.x-dev is an alias of laravel/framework dev-master and thus requires it to be installed too.