Microsoft Teams: Stricter external access controls for federated chats

Microsoft Teams introduces two new PowerShell controls to enforce stricter external access and mutual federation policies in federated group chats, enhancing admin control and reducing exposure to unapproved external organizations. These controls are disabled by default and roll out worldwide from July to September 2026. What and Why We’re introducing two new Microsoft Teams PowerShell controls that help organizations enforce external access and federation policies more consistently in federated group chats: External Access Restrictions for Chat Participants (EnableExternalAccessRestrictionsForChatParticipants) Mutual Federation for Chat Participants (EnableMutualFederationForChatParticipants) These controls are independent from each other and help ensure federated chat participation strictly aligns with configured external access policies. They help reduce indirect exposure to unapproved external organizations and provide admins with greater control over cross-tenant communications.  Rollout Schedule General Availability (Worldwide): Beginning late July 2026 and expected to complete late September 2026 External Access Restrictions for Chat Participants available: July 31, 2026 Mutual Federation for Chat Participants available: September 30, 2026 Impact on Your Organization Who is affected Microsoft Teams administrators managing external access and federation settings Organizations using federated group chats with external tenants Users assigned External Access Policies that restrict federation access Platforms/Services Microsoft Teams Teams PowerShell What will happen The new controls are disabled by default. The change only affects organizations that choose to enable the controls. The controls are configured through the existing Set-CsTenantFederationConfiguration PowerShell cmdlet. When EnableExternalAccessRestrictionsForChatParticipants is enabled: Users whose External Access Policy has EnableFederationAccess set to False cannot be added to federated group chats with external users. Those users are automatically removed from existing active federated group chats that include external participants. This setting does not change behavior controlled through the CommunicationWithExternalOrgs setting in External Access Policies. When EnableExternalAccessRestrictionsForChatParticipants is disabled: Users whose External Access Policy has EnableFederationAccess set to False can still participate in federated group chats if the chat was created by a user in their organization who is allowed to use federation. When EnableMutualFederationForChatParticipants is enabled: All federated group chat participants from tenants that have this setting enabled must be allowed to federate with the domains of the other tenants in the chat.  Users […]

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