Laravel 12 continues the lean application layout: fewer boilerplate files, middleware declared in bootstrap/app.php, and console scheduling living where you expect. If you are migrating from older majors, the biggest win is less hunting through empty classes.
Start by mapping your custom middleware and route groups to the new configuration style, then prune providers you no longer need. The framework conventions you already know—Eloquent, queues, and events—are unchanged.
Once the skeleton matches your mental model, upgrades become smaller diffs and easier reviews.