# Installation **Note:** this library requires **PHP 5.4**. All you need to do is to add `"chilldev/dependency-injection-extra": "dev-master"` to your `composer.json` file (replace `dev-master` with your desired constraint if you want to use particular version). Then run `composer.phar install`. **Note:** `dev-master` is a reference to `master` branch which is **stable** - to use current development branch with latest updates use `dev-develop`. That's all! Note that it's not a bundle, so you don't need to update your kernel code or anything else - just use library good directly in your code.