Get the hell out of Islands Mode
Hurry, hurry, choose wisely
What’s happening? More and more organisations are starting explore Microsoft Teams, and in doing this it’s important to understand the interopability options while running in coexistence (Skype for Business Online and Microsoft Teams next to each other).
Like all other vendors, backward compatibility is always difficult ;-) Teams is in this case no exception.
First of all, if your tenant was created before november 2018 you are probally running in Islands mode.