Fighting irssi switched their ircserver and the new does not have an AAAA only hostname, so i had to fight with my irssi, to persuade it to use ipv6.
Unfortunately the config file syntax is mostly undocumented. I had to figure out how to add servers via the commandline to find out that the magic is

family = "inet6"

Second it would be nice to have some kind of priority order, “First try the servers with autoconnect set, then the others” instead of the current topdown algorithm.