Teams Gains Ability to Start Chat with Email Address

A new Teams feature allows users to initiate chats with any email address. This caused some commotion in the security community, but it’s not that bad. In fact, it’s an extension of existing functionality that allows Teams users to chat with guest accounts. All that’s happening is that initiating a chat causes a new guest account to be created in the tenant, and there’s lots of controls to make sure that guests are controlled.

https://office365itpros.com/2025/11/10/chat-with-email-address-teams/