Update 7 October, 2016:
A patch update to both v2.8 and 2.9 is now available. Versions 2.8.4 and 2.9.1 should address IPv6 compatibility and be accepted for App Store submission and review. Release notes can be found here: https://tokbox.com/developer/sdks/ios/release-notes.html and here are links to the updated SDKs:
Update 6 October, 2016:
With the release of iOS 10.0.2, we have discovered a change in DNS resolution behavior that has broken IPv6 functionality for the OpenTok iOS SDKs. On IPv6 networks, version 2.8.3 will not connect to a session successfully in an IPv6 network, and 2.9.0 will fail to publish and subscribe. Apps submitted to the app store may not pass the review process until this is fixed. This is being treated as an extremely high priority issue and we are working hard to patch both 2.8 and 2.9 branches. Both branches will be released publicly as soon as possible.