Lumen 5.5 Released! What's New and First Look

Lumen 5.5 is now available for everyone. This is considered a maintenance release that upgrades the underlying packages to the Laravel 5.5 series.

Before upgrading your application to Lumen 5.5, you should review the Laravel 5.5 Upgrade Guide and make appropriate changes to your application based on the Laravel components you are using.
Once you have made the necessary adjustments to your application, you can upgrade the Lumen framework dependency in your composer.json file and run the composer update command:

"laravel/lumen-framework": "5.5.*"

For more information, please refer to the official Lumen documentation.

Lumen 5.5 New Features & Changes

So far, apart from the core changes, I haven't noticed any obvious changes in other features. Currently, the function in routes/web.php has changed. In all previous versions, $app was always used, but now it has been changed to $router:

$router->get('test','IndexController@test');