The setKeepAliveTimeout API is now deprecated in iOS 9 (as well as the other VoIP socket settings). How are current VoIP apps able to communicate when on a LAN without Internet access? The new solution as of iOS 8 is to use PushKit and funnel all requests for the app to wake-up from Apple's APNs. But these notifications will not arrive if on a private network.
Any ideas are welcomed, but unless I'm missing something; this as effectively killed a segment of VoIP apps from existing.