I've an application working since one year, now my client is asking to make a folder outside the App to place the contracts (PDFs) in.

The point is that the app is fully working and has many calls to the `base_url()` function, so I cannot change the config file `$config['base_url']` variable or my app will stop working.

So basically I need to go to the parent folder of my current app.

Let's say the base url is at `www.mysite.com/a/app/` I need to go into the `www.mysite.com/b/` folder.

My first idea was:

```
<?= base_url('../b') ?>

```

But of course does not work. Any idea?