Starting October 1, 2026, Microsoft begins phasing out Exchange Web Services (EWS), with a full shutdown by April 1, 2027. Sounds like a purely Microsoft-side issue — but it isn’t: many backup solutions for Exchange Online, including “Veeam Backup for Microsoft 365” and “Veeam Data Cloud for M365”, still rely on EWS for data protection today.
Here’s the catch: Microsoft Graph, the intended successor API, doesn’t yet cover every scenario backups need. Until that gap closes, EWS remains critical in the background — even as Microsoft winds it down.
The fix comes in two parallel tracks. On one side, organizations need to actively make sure EWS stays reachable for their backup application right now (think allow lists and app IDs), rather than relying on automatic transition rules. On the other, vendors like Veeam are already preparing the technical migration to Microsoft Graph, so backups can eventually run without EWS at all.
Do nothing, and you risk failing backup jobs — and once access is restored, a full resync with a gap in your data protection. Now’s the time to review your own M365 backup setup.
Important: This topic applies to both “Veeam Backup for Microsoft 365” and “Veeam Data Cloud for Microsoft 365” and all other Backup Solution which are using EWS!
More details: KB4820: What Microsoft’s EWS Retirement Means for Your Veeam Backups