Yes, it will work and you don't have to do anything.

We have not seen emails from the Internet coming in using IPv6. In order for IPv6 to work over the Internet, every router in between your Xeams and the sender's SMTP has to be compatible with IPv6. Since nobody knows when is that going to happen, most servers still use IPv4. Additionally, with the adaption of NAT the need for IPv6 has somewhat diminished and therefore, many companies have slowed down.