How to Prepare for Microsoft's EWS Retirement

Microsoft is permanently retiring Exchange Web Services (EWS) for Exchange Online by April 2027. If your OnTime still uses EWS, action will be required to maintain connectivity with Exchange Online.

While EWS continues to work today, Microsoft may begin disabling it by default in Exchange Online tenants in October 2026. Once this happens, OnTime installations that still rely on EWS may lose connectivity unless EWS has been added to your Microsoft EWS Allowed App IDs.

This means you have three options to continue as usual after September:

• Stay on your current OnTime version: Add OnTime to your Microsoft EWS Allowed App IDs to continue using EWS until April 2027.

• Upgrade to OnTime 6.4: Upgrade to OnTime 6.4 and add OnTime to your Microsoft EWS Allowed App IDs to continue using EWS until April 2027.

• Upgrade to OnTime 6.4 and migrate to Microsoft Graph (Recommended): Upgrade to OnTime 6.4 and transition to Microsoft Graph to remove your dependency on EWS and ensure continued connectivity after April 2027.

To make these different options and the process as simple as possible, we're hosting two webinars where we'll provide a step-by-step guide to configuring the EWS Allowed App IDs, explain the transition process, and what is means for you when moving to Microsoft Graph. Sign up today and make sure you're prepared!