Right now, Wildman’s server supports Yahoo! Messenger 6.0. Also, look at this: http://wink.messengergeek.com/t/how-to-patch-yahoo-messenger-6-0-0/2435
BTW, Escargot seems to be catching up on Yahoo! Messenger support (front/ymsg · master · Escargot / Escargot Server · GitLab)