An important sidenote is “Skype for Business” has nothing to do with Skype MSFT acquired. It’s just brand reuse to cover up their shitty product. What that product is? Good old MSN Messenger’s on-prem sister i.e. ms lync. In fact Skype for business main .exe is still lync.exe . This was acceptable in early 2000s. Now those outdated ui elements, confused windows and scrambled chat history, ignoring the offline messages after the first one. It’s wonky as hell to use in this day and age. At least there are some decent clients for open source platforms like matrix, mattermost, zulip etc. MS teams, MS Skype, MS anything is crap as always.