Microsoft warns Teams mobile users to update app now or lose Calendar access

• Microsoft Teams mobile users warned to update now
• Android and iOS users could risk losing access to their Calendar if not
• Deadline moved up to September 2026 as Microsoft likely reacts to end of life for EWS

Microsoft has warned Teams users that it has changed the date for them to update their smartphone apps, or risk losing access to the Calendar.

The company had originally said users of its Android and iOS apps would have until the end of October 2026 to update their services, but this deadline has now been brought forward to the end of September 2026.

Only the iOS and Android apps are affected, with web and desktop versions unaffected - and we would expect users with automatic updates enabled to get an updated version without needing to take any action.

Update Teams now

"To ensure continued access to Calendar functionality in Microsoft Teams mobile, users must update the Teams mobile app to the latest version," Microsoft wrote in its notice.

"This change helps maintain a reliable calendar experience on iOS and Android devices and ensures compatibility with ongoing Teams service updates."

Microsoft says those who aren't able to update (or forget, or ignore the warnings), "will not be able to access Calendar functionality in Teams mobile" - and nothing will be changing to Teams Calendar on desktop or web.

Users will need to update to version 8.9.0 (build 8.9.77.2026092302) or higher on iOS, and version 1416/1.0.0.2026122504 or higher on Android.

For those using at Teams on a work device - admins will need to make sure one of these updated versions are deployed before the deadline date.

The move appears to be linked to the upcoming end of support for Exchange Web Services (EWS) which allows apps to access mailboxes and other data in Exchange Online.

This is due to come into force on October 1, 2026, with shutdown having first been announced in 2023, following a number of high-profile security issues.

Microsoft notes that Teams admins can extend EWS until April 2027 if needed - however after that date,. it will no longer work.

Via The Register