Applies to: Microsoft Teams.
Harmonious and interactivity between Teams and Skype for Business is influenced by TeamsUpgrade modes. Everyone using Skype for Business is granted a TeamsUpgrade mode, either automatically or explicitly by their admin. If they’ve been given a coexistence mode, they’ll be able to get messages you send them from within Teams. Simply search for them in Teams, compose your message, and send it on its way. You’ll view a Skype for Business icon beside the chat in your chat list.
For further info about TeamsUpgrade modes: https://docs.microsoft.com/en-us/microsoftteams/coexistence-chat-calls-presence
Group chat with Skype for Business users
Unfortunately, group messages can’t be sent to people using Skype for Business. However, anytime someone invites you to a group conversation from Skype for Business, you’ll receive a notification in Teams. You’ll then find you can join the conversation back in Skype for Business.
Skype for Business vs. Teams
Actually chatting with someone on Skype for Business from inside Teams is pretty awesome, but you’ll be foregoing fun features like emoji, file attachments, and tabs.
Turn off Skype for Business
You can’t completely abandon the integration with Skype for Business. If you want to disable the chat option, though, speak to your IT admin.
Note: If your IT admin disables chat, you’ll still see all your Skype for Business meetings, but you won’t be able to chat with Skype for Business users.