When I try to call using WLM 2009 (Build14.0.8089.726) to another IM such as pidgin etc it is fail. The message error show ".... using a version of Messenger that does not have improvements to support a Computer Call. Please ask your contact to upgrade to the latest version of Messenger and try your call again".

I thing another IM (such as Pidgin, etc) has already use protocol WLM 2009 (Build14.0.8089.726) too inside their engine while login process.
What version should be used by another party to so that the call is working?

Any body can help?