Skype for Business, Client Feature Comparison
Not all versions of the Skype for Business client support the same features.
This web page has a detailed comparison of the capabilities of the Windows and MacOS Skype for Business clients:
https://docs.microsoft.com/en-us/skypeforbusiness/plan/feature-comparison
This web page compares the mobile editions of Skype for Business (Android and iOS) to the Windows client:
https://docs.microsoft.com/en-us/SkypeForBusiness/plan-your-deployment/clients-and-devices/mobile-feature-comparison