Supporting the transition to IPv6-only networking services for iOS

Apple announced that as of June 1, all apps submitted to the Apple Store must support IPv6-only networking. Most existing apps will not require changes due to their compatibility with Apple's NSURLSession and CFNetwork APIs. The transition from IPv4 to IPv6 is happening because IPv4 has a technical limitation of only allowing about 4 billion unique addresses, which is insufficient for the growing number of devices that need internet access. IPv6 uses a 128-bit address, allowing for approximately 340 trillion trillion trillion unique addresses. The adoption rate of IPv6 has increased significantly in recent years, with last year being a record year with a 4% increase. Developers should replace hardcoded IP addresses with domain names and avoid network preflighting to ensure code compatibility with IPv6 DNS64/NAT64 networks. CloudFlare offers various features for developers during their migration to IPv6, including Pseudo IPv4 which allows legacy IPv4 applications to take advantage of IPv6.