This is oddly worded to me and likely going to cause grief as it sounds like your app can only run on IPV6. I would interpret is as your app must be able to run internet connected when IPV4 is not available. This likely includes your local loopback if you are using 127.0.0.1 (which I infer from the hard code statement).

Or another weird to put it, your application must be IPV6 with the option of a IPV4 add-on.