enforce iOS to use IGMP v2 for multicast?

[Jeff Lu]

I'm working with an app that was developed with the CocoaAsyncSocket library, which uses <sys/socket.h> style socket programming. We have a customer where certain features are not working if iOS "adapts" to v3 IGMP but seems to work if v2 IGMP is used.

Is there a way to force iOS to use IGMP v2 for broadcast? Our company also makes a hardware communicator and their code forces v2 and we've been asked to see if we can do the same.

Thanks for any leads on where to go to inform myself. more or code snippets on how to do this.