Recently I cam across an unsupported scenario with Microsoft Teams. I logged in with an Office 365-account on which Teams is not enabled, giving me the following screen:
Translated, that is: “You’re missing out! Ask your IT administrator for access to Microsoft Teams.”
Microsoft Teams brings together the full breadth and depth of Office 365 to provide a true hub for teamwork. Word, Excel, PowerPoint, SharePoint, OneNote, Planner, Power BI and Delve are all built into Microsoft Teams so people have all the information and tools they need at their fingertips. It is available for Office 365 Business Essentials, Business Premium, and the Enterprise E1, E3, and E5 plans.
It puts itself in a strong competitive position against Slack.