First, I really like your program. Other clients I've used have way too much latency to be practical. I have IPv6 at home and on my mobile network. I'd prefer to use IPv6 when available to avoid NAT issues, but it doesn't let me register using IPv6 in Zopier. I receive the message "Registration failed (No DNS results (923))". I verified DNS was working on my phone by using "IPv6 and More" app and making TCP connections to Asterisk.