Microsoft Teams for iOS and Android: Update now or the calendar is gone

Microsoft has announced that users of its Teams mobile applications for iOS and Android must install an update by early October 2026, or they will lose access to the calendar feature. This change affects only the mobile apps, while the web-based application and desktop clients remain unaffected. The update requires specific versions of the apps: iOS users need version 8.9.0 (build 8.9.77.2026092302) and Android users require version 1416/1.0.0.2026122504. Microsoft did not explicitly state that the calendar functionality was the sole reason for the update, though it linked the requirement to the impending shutdown of Exchange Web Services (EWS) in Exchange Online. The EWS, a legacy SOAP-based interface used for accessing mailboxes, calendars, contacts, and other Exchange data, will be phased out starting October 1, 2026. Full access via EWS will be blocked beginning April 1, 2027. While administrators can temporarily extend the EWS availability, this does not replace the necessity of updating the Teams apps. Microsoft has moved the deadline for the required update forward from late October to earlier in the year, aligning with the gradual deactivation of EWS services. Microsoft recommends that administrators check the app versions currently being used by their users before October 2026 and ensure that end-users are informed about the update. For organizations managing mobile devices centrally, IT managers should verify that the latest versions of the Teams apps are installed on all affected devices. Additional information regarding this update is available in the Microsoft 365 Message Center under notification MC1440980. The shift away from EWS to Microsoft Graph represents a broader trend in Microsoft’s strategy to modernize its cloud services. By replacing older protocols with more secure and efficient APIs, Microsoft aims to improve performance and security across its platforms. However, this transition poses challenges for users who rely on legacy systems or have customized workflows tied to EWS. The calendar function, which many users depend on for scheduling and coordination, is particularly vulnerable to disruption unless updated promptly. Administrators and IT departments face the task of ensuring smooth migration to the new system. Some organizations may encounter difficulties if they have not yet begun planning for the EWS shutdown. Microsoft has not provided detailed guidance on how to test the new setup or troubleshoot potential issues arising from the update. As a result, some experts suggest that businesses should start preparing now to avoid disruptions during the transition period. Users who fail to update their Teams apps by early October 2026 will find that the calendar feature becomes inaccessible. While other functions within Teams appear to remain functional without the update, the loss of calendar access could significantly impact productivity, especially for teams relying heavily on shared schedules and reminders. Microsoft has not indicated whether alternative methods of accessing calendar data will be available for non-updated apps, leaving uncertainty for users who may be unable to apply the update for various reasons.