Laravel API versioning using the Accept-Version header

app\Http\Controllers\Api\Controller.php

<?php

namespace App\Http\Controllers\Api;

use App\Http\Controllers\Controller as BaseController;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

abstract class Controller extends BaseController
{
    protected $realClass;

    public function __construct()
    {
        $this->realClass = sprintf(
            '%s%s\\%s',
            rtrim(__CLASS__, class_basename($this)),
            studly_case(config('api.version')),
            class_basename($this)
        );
    }

    public function __call($method, $parameters)
    {
        if (! class_exists($this->realClass)) {
            throw new NotFoundHttpException;
        }

        if (! method_exists($this->realClass, $method)) {
            throw new NotFoundHttpException;
        }

        return app()->call(sprintf('%s@%s', $this->realClass, $method), $parameters);
    }
}

app\Http\Middleware\ApiVersion.php

<?php

namespace App\Http\Middleware;

use Illuminate\Http\Request;

class ApiVersion
{
    public function handle(Request $request, $next)
    {
        if ($version = $request->header('Accept-Version')) {
            config(['api.version' => $version]);
        }

        return $next($request);
    }
}

config\api.php

<?php

return [
    'version' => 'v1',
];