Updated advisory as of July 17, 2026. We will continue to provide new updates and guidance as we get closer to the September release milestones. - Commvault Support & Community teams
For customers and partners backing up Microsoft 365 and Exchange Online in your environments, we have published a new KB article with more details about this transition, actions Commvault is taking, and recommendations for different customer segments. We suggest clicking “subscribe for updates” and we will also provide a heads up here in the Community and through direct outreach to impacted customers later in the summer.
What is Changing?
Microsoft is making a phased transition from the 20-year-old EWS architecture to the modern, REST-based Microsoft Graph API. This shift enhances security via OAuth-based authentication and provides a more unified architecture across Microsoft 365.
To ensure long-term compatibility, security, and supportability, Commvault is adopting Microsoft Graph for Exchange Online protection. Because Microsoft Graph does not yet support every Exchange Online workload, Commvault will use a hybrid transport model until the Microsoft transition is complete.
Microsoft EWS Retirement Timeline
Per Microsoft, below is the revised planned transition timeline for EWS. (Note they have removed the previously communicated June 2026 milestone to phase out some EWS access.)
- October 1, 2026: Phased disablement of EWS begins (tenant-controlled).
- April 1, 2027: EWS permanently retired for all Exchange Online tenants.
⚠️ IMPORTANT: This change applies only to Exchange Online. On-premises Exchange Server environments are not impacted by this deprecation.
Planned Commvault Milestones & Timings
We understand that your backup continuity is non-negotiable. Our hybrid approach and timeline is intended to ensure your environment is "Graph-ready" before Microsoft begins the phased disablement in October 2026 and also that there is continuity for workloads not yet fully supported by Graph.
We recommend reading the latest KB article for details by deployment type, but below is a brief summary.
For Commvault Cloud SaaS (Metallic) customers, Commvault will automatically enable the Graph API as the primary mode of transport beginning in September. From the customer side, the only action that should need to be taken is verification of permissions against the Azure applications you have configured. A small number of customers using legacy single-tenant Azure apps may need to do additional configuration of permissions as noted in the KB article, and you will receive a notification in-app.
For self-hosted / on-premises software customers with Exchange Online, Commvault plans to release a hotfix cycle for 11.44 in early September where, similar to SaaS, the Graph API will be enabled by default. To continue protecting your Exchange Online mailboxes after Microsoft retires EWS in April 2027, you will need to upgrade to Commvault 11.44 or later. Once deployed, the only action required by the customer is to verify the Azure apps being used for the workload have the appropriate permissions to use the Graph API. There is more detail around these steps in the KB article here.
Recommended Actions for Administrators to Prepare
Review the new KB article here for more detailed guidance and recommended actions by deployment type, including steps related to verifying and/or reauthorizing Azure AD applications where and when needed.
Dependency on the Microsoft Ecosystem
As a Microsoft partner, Commvault’s development timeline is inextricably linked to Microsoft’s API release schedule. While Graph is the future, Microsoft has acknowledged that it does not yet have full feature parity with EWS. This is an ongoing process and subject to further changes as Microsoft continues to evolve their release plans and dates.
Other reference links:
The previous Commvault KB article contains more general context around the Microsoft transition and timings.
For full Microsoft guidance, take a look at this blog post from their Exchange team and this Microsoft Learn article.
Stay Tuned
We will continue to share updates, timelines, and guidance here and through the new KB article.
As always, don’t hesitate to post questions here or reach out to your account team.
