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Action required after October 1, 2026 to continue using EWS (which is permanently disabled in April 2027):
Organizations using Q360 Calendar on v24 or earlier with Microsoft Exchange Online may experience a calendar sync interruption. Read this article to understand your options.
Microsoft is deprecating Exchange Web Services (“EWS”) in Exchange Online.
This change affects Q360 Calendar integrations on versions prior to Q360 v25.
What is changing
EWS is the API that older versions of Q360 Calendar use to sync appointments and availability with Microsoft Exchange Online (Microsoft 365 / Office 365).
Microsoft’s timeline:
October 1, 2026 — Microsoft automatically disables EWS across Exchange Online tenants that have not opted out. See the EWS deprecation timeline for full details of this process.
April 2027 — EWS is permanently and fully disabled, with no further extensions.
Who is affected
You are affected if all of the following apply:
a) You are on Q360 v24 or earlier
b) You have Q360 Calendar integration enabled
c) Your organization uses Microsoft Exchange Online (Microsoft 365 or Office 365)
Organizations on Q360 v25 or later are NOT affected; Q360 v25 migrated Calendar to the Microsoft Graph API.
What you need to do
The permanent solution is to upgrade to Q360 v25 or later.
If you are on Q360 v24 or lower, contact Solutions360 Support at support@solutions360.com to start your upgrade.
If you cannot upgrade before October 1, 2026
Microsoft does provide temporary options to keep EWS available past October 1, 2026. The key points:
Act before September 30, 2026 — Organizations that proactively configure their tenant settings before the end of September 2026 can avoid the automatic October 1, 2026 disruption entirely.
After October 1, 2026 — If EWS is blocked, a Microsoft 365 administrator can re-enable it, but there will be a service interruption in the interim.
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** Note: These options extend access only until April 2027, when EWS is permanently disabled. **
Sources: For the specific steps your Microsoft 365 administrator needs to take, see Microsoft’s own guidance:
- Deprecation of Exchange Web Services in Exchange Online > EWS Deprecation Timeline (Microsoft Learn) — includes Microsoft’s full timeline and links to further details on the October 2026 disablement process, including the one below
- Exchange Online EWS, Your Time is Almost Up (Exchange Team blog, 2026-02-05) — refer to the Key dates section for a visual timeline, and the section beginning “But if you still need to use EWS, you will have two choices…” for opt-out steps your administrator can take
Reference v25 Release documentation:
- Release Notes 25.01 and Release Notes Advisories 25.01 – includes deprecation of EXCHANGE_CAL_SYNC configuration (US41960475, US35596738, US44142471, US44142480)
Questions?
- Contact Solutions360 Support: support@solutions360.com