Since a while the Menu Button has disappeared from Lync (note that the HTC One hasn't got a menu button of its own). I can no longer log out! Also, I am no longer able to join a Lync conference call using the mobile Lync client. When I reinstalled Lync 2010 I found out I could not configure my Exchange account anymore - because of the missing Menu Button :-(
Has Microsoft placed a wrong s/w update in Google Play store?