Since version 2009 there's no addition to support more IM applications and no more update for latest version...
Just like Trillian, there's no support for the version 4 (I'm using it) and the new beta version 5. Also there's bunch of IM applications like Miranda and Pidgin (the famous one).
I hope there's update for the latest and more IM applications. Just for the info, I never using YM and WLM for years... using Trillian since version 3.1 until now 4.2 about 3 years.
sorry if my English is bad...