为slim路由器添加基本URL路径

I have a bunch of routes and they all start with /api/2.01.

How can I add it once so it applies to all routes. Slim Framework Base URL asks the same question, but I believe provides an outdated answer.

PS. If instead of asking a new question, should I have instead somehow tagged the post which I believe is dated to be reviewed or something?

$app = new \Slim\Slim();
$app->post('/api/2.01/books', function () {
    //Create books
});
$app->get('/api/2.01/books', function () {
    //getbook
});
$app->get('/api/2.01/books/{id}', function () {
    //Get book
});
$app->delete('/api/2.01/books/{id}', function () {
    //Create book
});

If you are using Slim v2.0, you can do somtehing like:

// API group
$app->group('/api', function () use ($app) {

// Library group
$app->group('/library', function () use ($app) {

    // Get book with ID
    $app->get('/books/:id', function ($id) {

    });

    // Update book with ID
    $app->put('/books/:id', function ($id) {

    });

    // Delete book with ID
    $app->delete('/books/:id', function ($id) {

    });

});

as specified in the docs: http://docs.slimframework.com/routing/groups/