You no longer need to enable or configure anything. The anti-spam filter is active by default on every Mapaprop website and protects your forms without you doing a thing.
This tutorial used to explain how to create a Google reCAPTCHA account, get the keys and enter them in Mapaprop. That step no longer exists.
How it works and which forms it covers: Anti-spam protection on your website
If your site still has reCAPTCHA keys saved from before, they keep working. You do not have to remove or replace them.