If a user attempts to join an Office 365 Skype for Business web conference and they don't have the native client installed (inc. the older Lync client), they have the option to install the Skype for Business Web App plug-in* . This doesn't need administrator rights to install which is great but on joining the meeting there is a firewall prompt for which admin rights are needed without which some features are blocked.
The question is which features are blocked?
* SkypeForBusinessPlugin.msi
