With my bip proxy IPv6 enabled it is time to look at my IRC client. I am a 'weechat' user so that is my target. It seems that weechat has some support for IPv6 via its 'ipv6' option on the server configuration block. You can set this option for connection 'freenode' as below:
/set irc.server.freenode.ipv6 yesThis certainly switches the connection over to IPv6, but it does not seem to fallback to IPv4 automatically. Some additional support will be required to handle this, though the changes look minor. I guess we can call this half enabled.