Do I need to replace NSURLConnection in order to achieve mandatory support for IPv6-only services? : <p>As Apple is requesting app submitted for review must support IPv6-only network starting from 1st June 2016, I am checking if I need to replace certain API / libraries in my app. However I don't know much enough about networking and some related aspects, as a result I am unable to have a definite answer on this and would like to seek for help.</p>

<p>Regarding the document <a href="https://developer.apple.com/library/mac/documentation/NetworkingInternetWeb/Conceptual/NetworkingOverview/UnderstandingandPreparingfortheIPv6Transition/UnderstandingandPreparingfortheIPv6Transition.html#//apple_ref/doc/uid/TP40010220-CH213-SW13" rel="noreferrer">Supporting IPv6 DNS64/NAT64 Networks</a> provided by Apple, it states that apps should be fine and no need to perform update if:</p>

<blockquote>
  <p>you’re writing a client-side app using high-level networking APIs such
  as <strong>NSURLSession</strong> and the <strong>CFNetwork frameworks</strong> and you <strong>connect by name</strong></p>
</blockquote>

<p>By this I take it as 2 criteria:</p>

<ol>
<li>using NSURLSession or CFNetwork</li>
<li>connect by name</li>
</ol>

<p>So the question here is:</p>

<ol>
<li><p>As far as I know NSURLConnection is based on CFNetwork, does this mean I will be fine too if my app is using NSURLConnection? (I saw NSURLConnection is also mentioned in <a href="https://developer.apple.com/library/ios/documentation/NetworkingInternetWeb/Conceptual/NetworkingOverview/art/NetworkingFrameworksAndAPIs_2x.png" rel="noreferrer">this image in the above document</a>, but again I am not quite sure about this as NSURLConnection is kind of old? And seems I cannot find documents mentioning IPv4 and IPv6 support either.)</p></li>
<li><p>By the criteria "calling by name", does this mean no matter I am using NSURLSession or NSURLConnection, if I happen to call or access certain resources / APIs by an IPv4 address, bad things will happen? (I've done some research, and from my understanding clients like iOS device with iOS 9+ will always use synthesized IPv6 address to access IPv4 server, as a result the client will fail to reach the resource if I call by IPv4 address?)</p></li>
</ol>

<p>Thanks for any help!</p>
