Microsoft Teams voicemail messages in Exchange will see compliance and security enhancements, including updated 'From' fields to meet RFC 6854 standards and labels for external or unverified calls. Rollout begins December 2024, with no admin action required. Users should be informed of these changes.
We are pleased to inform you that we will roll out two improvements to enhance compliance and security for voicemail messages in Microsoft Exchange.
This change is related to three products: Microsoft Teams calls, Microsoft Outlook/Exchange, and Microsoft Skype for Business calls. Results will be visible in Outlook/Exchange email messages.
When this will happen:
General Availability (Worldwide, GCC): We began rolling out early December 2024 and expect to complete by late January 2025.
General Availability (GCC High, DoD): We will begin rolling out early January 2025 and expect to complete by mid-February 2025.
How this will affect your organization:
1. The From: field of voicemail email messages will be updated to comply with the latest RFC standard, RFC 6854: Update to Internet Message Format to Allow Group Syntax in the From: and Sender Header Fields. According to this compliance standard, the Internet message format must always include an address in the From header field.
Example:
2. To strengthen trust and security in voicemails received from external PSTN calls and from federated tenants, Unverified and External tags will always be added to the From field of voicemail messages in the mailbox.
| Voicemail message type | Label |
|---|---|
| Voicemail messages from external PSTN callers that are found in Entra ID contacts | External |
| Voicemail messages from federated tenant callers that are found in the federated Entra ID contacts | External |
| Voicemail messages from external PSTN callers that are not found in Entra ID contacts | Unverified |
| Voicemail messages from anonymous callers, for example Skype calls without a phone number | Unverified |
Note: This rollout applies to voicemail messages in Microsoft Exchange received from external PSTN calls and calls from federated tenants.
Example of the From field in voicemail message if PSTN caller was not found in Entra ID contacts:
Example of the From field in voicemail message if PSTN caller was found in Entra ID contacts:
Example of the From field in voicemail message for calls from federated tenant:
Example of the From field in voicemail message for anonymous Skype calls:
Note: Both improvements will always be on by default.
What you need to do to prepare:
This rollout will happen automatically by the specified date with no admin action required before or after the rollout. You may want to notify your users about this change and update relevant documentation.