Since IPv6 is going to replace IPv4, should I develop my new application to support it?

Question

I develop applications using many languages and a few platforms. From what I am reading, IPv6 is going to be mainstream within then next 5–10 years, and that some ISPs even offer direct connection to the IPv6 Internet. On my private network, all the machines have dual stack connectivity and communicate with each other using IPv6 when possible.

My question is: should my new application be written to support IPv6? If so, what are the things I need to consider? Are there any downsides to supporting IPv6 now?

I don't know if this will help or hurt, but here are some more specific details to maybe direct the answers a little:

My app would run on Windows/Linux/Mac, and it would consist of a platform–specific component written separately for each platform, and a common "core" component written in an interpreted language.

My app should be able to locate other instances of itself running on any of the three platforms, and support both TCP and UDP between any two machines.

Answer 1

Yes: all of your new applications should support IPv6. As you've said yourself, it is already being used in many LAN environments.

No: you shouldn't have to change much in order to support IPv6. The underlying framework should take care of the differences for you. This assumes that you aren't doing "bad" things like storing or otherwise manipulating IP addresses.