Microsoft is sunsetting Exchange Web Services (EWS), and while that may sound dramatic, there's no cause for alarm — especially if you're working with a forward-thinking backup provider. Understanding this transition is crucial for maintaining robust data protection strategies.

What's Happening with EWS?

EWS, the protocol introduced in 2005 to access Exchange mailbox data, will be fully retired by April 1, 2027, with a controllable disablement plan starting in October 2026. But the real shift has already started — Microsoft is updating its own applications and services to stop using EWS.

In mid-October 2025, Microsoft released a message center notification to Microsoft 365 tenant admins reminding them of this change. You'll likely see press headlines that say things like "Microsoft is moving away from EWS, an outdated, insecure technology" — which might sound worrying. But this is a Microsoft-wide transition and has been on the roadmap for a long time.

Understanding Exchange Web Services

Microsoft Exchange Web Services is a RESTful protocol that Microsoft introduced in 2005 to enable access to Exchange mailbox data — like emails, calendars, and contacts. It became the standard interface for Exchange and has been widely adopted by Microsoft and by third-party application developers throughout the industry.

For nearly two decades, EWS has been central to how data is accessed and managed in Microsoft Exchange environments. Over the last decade, Microsoft has been replacing various APIs with a more modern, more secure, and more unified alternative: Microsoft Graph.

Microsoft Graph: The Modern Alternative

Of course, Microsoft Graph isn't new. It's one unified protocol that spans the entire Microsoft 365 platform and across other Microsoft services. The move from EWS to Graph isn't new either; it's been in progress, slowly, for years. What's changing now is the timeline: The shift is entering its final phase.

So, while it might come as a surprise to some, Microsoft has been preparing for this and is doing everything to ensure the transition from EWS to Graph is smooth.

Impact on Microsoft 365 Backup Solutions

The upcoming changes affect all Microsoft 365 customers and vendors — not just individual backup providers. Organizations that work closely with Microsoft have known about this transition for a long time and are already ensuring a smooth, seamless shift.

As Microsoft adds new capabilities to Graph to bring it closer to parity with EWS functionality, modern backup solutions are integrating those Graph changes into their products. Between now and April 1, 2027, Microsoft will continue to make incremental changes. There may be minor adjustments behind the scenes, but organizations shouldn't notice anything that impacts their data protection.

A Gradual, Managed Transition

Think of it like a house renovation: Microsoft is improving one room at a time, not tearing the whole structure down. As they gradually enhance Microsoft Graph, backup providers have already started using those new capabilities to replace EWS. The shift will happen step by step.

The goal is to deliver the same quality of experience, stability, performance, security, and ease of use as the industry moves to a 100% Graph-powered world. Ultimately, though, Microsoft gets a vote too. They may choose not to bring some EWS functions over to Graph.

Known Limitations and Considerations

For example, Microsoft has already announced that they will not support backup and restore of Exchange public folders using Graph. Organizations that currently back up public folders using EWS-based solutions need to be aware of this limitation.

When Microsoft removes EWS, customers who back up public folders will be impacted. Leading backup providers are continuously giving Microsoft feedback as they update their plans, and documentation is being updated to identify any areas where Microsoft is choosing not to bring Graph to full parity with EWS.

Preparing Your Organization

Here are key steps to prepare for the EWS sunset:

Stay informed: Keep track of Microsoft's announcements and your backup provider's communications about the transition.

Review your backup scope: Identify if you're backing up Exchange public folders or other features that may be affected by the transition.

Test your recovery processes: Ensure your backup and recovery procedures continue to work as expected during the transition period.

Communicate with stakeholders: Keep your team and management informed about the changes and any potential impacts.

Work with your vendor: Maintain open communication with your backup provider to understand their transition roadmap and any actions you need to take.

The Importance of Vendor Partnership

This transition highlights the importance of working with backup vendors who maintain close relationships with Microsoft and stay ahead of platform changes. Organizations should look for providers who:

- Have established partnerships with Microsoft
- Proactively communicate about platform changes
- Demonstrate a track record of smooth transitions during API updates
- Provide transparent documentation about feature parity and limitations
- Invest in continuous product development to align with Microsoft's roadmap

Looking Forward

The transition from EWS to Microsoft Graph represents Microsoft's commitment to modernizing its platform with improved security, performance, and unified access across services. While change can feel disruptive, this particular transition has been carefully planned and communicated well in advance.

For organizations with the right backup partner, this transition should be seamless. The key is ensuring your backup provider is aligned with Microsoft, committed to the transition, and transparent about any limitations or required actions.

Final Recommendations

There's no need to panic about the EWS sunset. Prepared organizations and vendors are aligned with Microsoft and committed to ensuring Microsoft 365 backup remains stable and secure throughout the transition.

Focus on maintaining open communication with your backup provider, staying informed about the transition timeline, and testing your backup and recovery processes regularly. By taking these proactive steps, your organization can navigate the EWS sunset smoothly and continue to maintain robust data protection for your Microsoft 365 environment.

This article was inspired by insights from Keepit Blog on the Microsoft EWS transition and its implications for data backup.