Microsoft warns that users of the mobile version of Microsoft Teams must update their apps to keep access to Calendar features. According to reports, the change affects Teams on mobile devices and is tied to an upcoming deadline. If users do not update in time, they will lose Calendar access within the Teams app. Mashable says users need to update as soon as possible to avoid losing Calendar functionality “in weeks,” while TechRadar reports a specific end-of-September 2026 cutoff. Both outlets frame the issue as a required update rather than a service outage, urging users to install the latest version of the Teams mobile application. The warning indicates Microsoft is likely retiring or discontinuing older app versions’ support for the Calendar integration. Users who update the app are expected to retain Calendar access through the Teams interface, while those who remain on outdated versions may no longer be able to use Calendar features after the stated deadline.