Laravel 12: New Features, Helpers, and Practical Upgrade Notes

What Actually Changed in Laravel 12

Laravel 12 is a focused release. Rather than introducing sweeping new subsystems, it tightens existing APIs, removes long-deprecated paths, and ships opinionated starter kits that reflect how the community actually builds apps today. If you are running Laravel 11 on PHP 8.2+, the upgrade is low-friction — but a handful of changes will bite you if you skip the release notes.

Starter Kit Overhaul

The most visible change is the replacement of the old Breeze and Jetstream scaffolding with a unified laravel new experience. The new stacks are:

• React + Inertia (TypeScript-first)
• Vue + Inertia (TypeScript-first)
• Livewire (Volt or class-based)
• API-only (no frontend)

The installer now asks which stack you want and wires everything — Vite config, auth scaffolding, and Pest — in one pass. There is no separate breeze:install step.

laravel new my-app
# Prompts: stack, testing framework, git init

Existing projects are unaffected; the starter kits are only relevant at project creation time.

Application Bootstrap Cleanup

Laravel 12 removes the Http/Kernel.php and Console/Kernel.php files that were already deprecated in Laravel 11. If you upgraded from Laravel 10 and kept those files, they will now be ignored entirely — but any customisation inside them will silently disappear.

Action required: Audit your kernels before upgrading. Move any custom middleware registration to bootstrap/app.php:

// bootstrap/app.php
return Application::configure(basePath: dirname(__DIR__))
    ->withRouting(
        web: __DIR__.'/../routes/web.php',
        api: __DIR__.'/../routes/api.php',
    )
    ->withMiddleware(function (Middleware $middleware) {
        $middleware->append(\App\Http\Middleware\EnforceJsonResponse::class);
    })
    ->withExceptions(function (Exceptions $exceptions) {
        $exceptions->render(fn (\App\Exceptions\DomainException $e, Request $r) =>
            response()->json(['error' => $e->getMessage()], 422)
        );
    })
    ->create();

Typed Route Model Binding Improvements

Laravel 12 makes implicit route model binding respect PHP 8.x union types and intersection types on controller method signatures. Previously, a union-typed parameter would fall back to the default resolver. Now the container inspects the concrete type and resolves accordingly.

// Before Laravel 12: union type caused silent fallback
public function show(Post|Page $resource): Response
{
    // $resource was always the raw route segment string
}

// Laravel 12: resolves the first bindable type found in the union
public function show(Post|Page $resource): Response
{
    // $resource is a hydrated Eloquent model
}

This is opt-in via the Illuminate\Routing\Contracts\BindingRegistrar interface on your model. If neither type implements it, the old behaviour is preserved.

Removed Deprecations Worth Noting

| Removed | Replacement | |---|---| | Route::prefix() chained on group closures without array | Pass options array directly | | $this->middleware() in controllers (constructor style) | Use #[Middleware] attribute | | Str::replaceArray() | Str::replaceMatches() or native str_replace() | | assertExactJson strict key ordering | assertExactJsonStructure |

Minimum PHP Version

Laravel 12 requires PHP 8.2. PHP 8.1 is dropped. If you are still on 8.1, upgrade PHP first — the language changes (readonly classes, never return type, DNF types) are worth it independently.

Upgrade Checklist

• Run composer require laravel/framework:^12.0 and fix any immediate constraint conflicts.
• Delete app/Http/Kernel.php and app/Console/Kernel.php after migrating their contents.
• Search for Str::replaceArray and $this->middleware( in controllers.
• Run php artisan route:list and confirm no routes silently broke.
• Execute your full Pest suite — binding changes can surface as 404s in feature tests.

Key Takeaways

• The kernel files are gone; bootstrap/app.php is the single configuration surface.
• Starter kits are rebuilt from scratch — existing projects are unaffected.
• Union-typed route model binding now works correctly without a workaround.
• PHP 8.2 is the floor; plan your server upgrade before touching composer.json.
• The removed deprecations are small but silent — a thorough test suite is your safety net.