Microsoft is preparing to make Teams a bit more secure this month with the rollout of brand impersonation protection for Teams Calling. It will start by mid-May 2026 to help warn users about suspicious inbound calls from first-contact external callers who could be impersonating trusted brands. With this, Microsoft hopes to reduce social-engineering fraud and improve tenant security.
This feature will get a targeted release beginning in mid-May and it is set to complete by late May. This arrival window is slightly later than first proposed. The general availability is still TBD, but hopefully Microsoft won’t take too long in pushing it to everyone.
The feature works by evaluating inbound VoIP calls from first-contact external callers for brand impersonation signals. High-risk call warnings will appear before you can answer suspicious calls. If the risk signals continue, then users will continue to get warnings during the call. This feature will be on by default for all tenants, but recipients still have the control and can accept, block, or end the call.
The change will be arriving for all organizations that use Microsoft Teams Calling and receive inbound VoIP calls from first-contact external callers. Microsoft mentions that no changes will be made to existing Teams Calling policies and no admin configuration will be needed to turn on the feature.
Admins are advised to tell helpdesk staff that users may see high-risk call warnings, update any internal training materials if Teams Calling security is covered, and watch out for Microsoft documentation on caller ID security, which will be linked before rollout.
You can find out more on the Microsoft 365 Admin Center under Message ID MC1219793.