Microsoft has announced that Group chat with external users in Microsoft Teams is now Generally Available.
The new external group chat feature enables users to initiate and participate in group Teams chats with users from outside your organization, as long as those users have an AAD identity. The organizations are required to use the open federation policy or be on each other’s allow list.
Open federation is the default setting in Teams. Admins can limit this in the Teams Admin Center and all legacy settings will be honoured.
The feature expands on the existing ability for Teams users to find, participate in 1:1 chat, call and set up meetings with external users.
Once your organization is federated with another organization, users can initiate a chat in the same way they would with someone inside their organization. Simply tap on the new Chat icon, enter the email address of the recipient, and tap the Search externally option to find the user. You can add up to 250 participants to a single group chat.
The feature will begin rolling this out in mid-May and is expected to complete rollout in late July and is rolling out on Teams desktop, web and mobile.