Many things to be improved
Just to remind you: while Skype, Hangouts and other good conference tools are free you have to pay for an office 365 subscription to be able to use this app. But anyway this app is really crap as other current Microsoft apps (Outlook). As others wrote many things do not work, e. g. Conference calls with Skype users or starting a presentation with is available on OneDrive.
I really need to consider leaving the Microsoft universe.
Oli,71 about
Skype for Business, v6.6.1