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 offe

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.