Do I really need an ERN to publish an iOS in the app store?

I'm new to this forum, so I'm not sure if this is the correct place or way to ask. Forgive me if it's not, I am getting desperate about this issue. I have an app in the app store that uses the Flickr API and a friend of mine recently pointed me to this blog post about how if I use an API I need an ERN or something like that: http://ift.tt/1OVz9Oq

I asked the freelancer coder that built it for me and he said that he knew nothing about it. I'm confused. Is this true? do I need to get an ERN to publish an app in the iOS store when it's using the Flickr API?