Field Notice: FN74365 - Cisco Unity Connection Unified Messaging with Microsoft 365 - Voicemail Stored in Cisco Unity Connection Will Not Sync with Exchange Online (Outlook) Due to EWS Deprecation - Software Upgrade Recommended

Available Languages

Updated:April 15, 2026

Document ID:FN74365

Bias-Free Language

The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.

High

Impact Rating:

High

First Published:

2026-Apr-15

Last Published:

2026-Apr-15

Revision:

1.0

Cisco Bug IDs:

CSCwp95908

Notice

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.

Products Affected

Affected Software Product	Affected Release	Affected Release Number	Comments
Unity Connection Updates	14	14	All releases are affected.
Unity Connection Updates	14SU1	14SU1
Unity Connection Updates	14SU2	14SU2
Unity Connection Updates	14SU3	14SU3
Unity Connection Updates	14SU3a	14SU3a
Unity Connection Updates	14SU4	14SU4
Unity Connection Updates	14SU5	14SU5
Unity Connection Updates	14SU6	14SU6
Unity Connection Updates	15	15	All releases earlier than 15 SU4 are affected.
Unity Connection Updates	15SU1	15SU1
Unity Connection Updates	15SU2	15SU2
Unity Connection Updates	15SU3	15SU3

Defect Information

Defect ID	Headline
CSCwp95908	Implement Graph API support for office 365 in unity connection.

Problem Description

Cisco Unity Connection uses Exchange Web services (EWS) for syncing Voicemail deposited on unity with Microsoft 365 (Exchange online) and on-prem Exchange. Beginning October 1, 2026, Cisco Unity Connection will not sync voicemail with Microsoft 365 as Microsoft will start deprecating Exchange Web Service (EWS) for Exchange online alone (not for on-prem exchange).

Background

Microsoft is deprecating EWS for third-party applications to integrate with Microsoft 365 and replacing it with Graph API. Beginning October 1, 2026, Microsoft will block EWS requests from non-Microsoft apps (including Cisco Unity Connection) to Microsoft 365.

Microsoft announcement: Retirement of Exchange Web Services in Exchange Online

Note: This applies only to Microsoft 365 and Exchange Online (all environments). There are no changes to EWS in Exchange Server. EWS will continue to be fully supported for Exchange on-premises mailboxes.

Problem Symptom

Voicemail, which is stored in Cisco Unity Connection, will not sync with the Microsoft 365 - Exchange (Outlook) email inbox when using the Single Inbox (Unified Messaging Service) feature.

Cisco Unity Connection users will not be able to read voice messages using Microsoft 365 (Outlook).

Administrators will see the error Failed to Connect to Microsoft endpoint using https://outlook.office365.com when choosing the Test function in the Cisco Unity Connection admin console.

Workaround/Solution

Solution

Cisco Unity Connection will migrate to Graph API in releases 15 SU4 and later. Upgrade to Release 15 SU4 before October 1, 2026, as shown in the following table. Upgrading is the only option to sustain Unified Messaging Service.

Cisco Unity Connection Release	Affected Build number	First Fixed Release
14	14.0.1.10000-19	15 SU4
14 SU1	14.0.1.11900-128
14 SU2	14.0.1.12900-69
14 SU3	14.0.1.13900-70
14 SU3a	14.0.1.13901-2
14 SU4	14.0.1.14900-36
14 SU5	14.0.1.15900-25
14 SU6	14.0.1.16900-10
15	15.0.1.10000-24	15 SU4
15 SU1	15.0.1.11900-14
15 SU2	15.0.1.12900-43
15 SU3	15.0.1.13900-61

Revision History

Version	Description	Section	Date
1.0	Initial Release	—	2026-APR-15

For More Information

For further assistance or for more information about this field notice, contact the Cisco Technical Assistance Center (TAC) using one of the following methods:

Receive Email Notification About New Field Notices

To receive email updates about Field Notices (reliability and safety issues), Security Advisories (network security issues), and end-of-life announcements for specific Cisco products, set up a profile in My Notifications.

Was this Document Helpful?

Feedback

Contact Cisco

Open a Support Case
(Requires a Cisco Service Contract)