Supporting IPv6-only Networks. Starting June 1, 2016, all apps submitted to the App Store must support IPv6-only networking. A majority of apps will not require any changes as IPv6 is already supported by NSURLSession and CFNetwork APIs.
In Mac OS X 10.2 Jaguar, Apple introduced IPv6 support. Like other IPv6-capable operating systems, Mac OS will prefer IPv6 over IPv4 if it has a choice. That is, until yesterday's 10.6.5 Snow How to prefer IPv6 on the Mac OS X Sierra? - Google Groups > Subject: Re: How to prefer IPv6 on the Mac OS X Sierra? > > Congrats, Simon! Big job, huh?
Comparison of IPv6 support in operating systems - Wikipedia
10.4: Disable IPv6 networking for - Mac OS X Hints
Jun 19, 2015 · He also explained how Apple has supported IPv6 for over ten years now since early versions of Mac OS X and from iOS 4 onward. 3 Steps For Developers. He went on to explain three steps all developers can take to make sure their applications work over IPv6 networks: Those steps are: Use the networking frameworks (for example, “NSURLSession”)
How to Obtain the IPv6 Address of Your Mac and iPad Aug 30, 2013