Teams mobile users now have even less time to update the app before older versions lose calendar access.

Microsoft originally set a late-October deadline in its message, but we're guessing someone familiar with the impending demise of Exchange Web Services (EWS) had a quiet word. The date has been brought forward to the beginning of October, leaving users until the end of September to update the Teams mobile app.

The October deadline applies only to the iOS and Android apps. The web and desktop versions are unaffected.

Users with automatic updates enabled will probably receive a compatible version without doing anything. Managed devices are another matter, and administrators will need to ensure an updated Teams app is deployed, though we can't imagine why they might hesitate to roll out one of Microsoft's updates.

Microsoft has stern words for refuseniks: "Older versions will lose calendar access."

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

Microsoft will begin disabling EWS in Exchange Online on October 1, 2026. The service stopped receiving feature updates in 2018, its retirement was announced in 2023, and Microsoft detailed the shutdown process earlier this year.

EWS allows applications to access mailboxes and other data in Exchange. It dates to 2007 and has proved popular with both integrators and miscreants, including those behind the Midnight Blizzard intrusion. Microsoft is understandably keen to shut it down.

EWS in on-premises Exchange Server is unaffected, but the Exchange Online version is heading for retirement. Administrators can re-enable it temporarily through a policy setting, but the plug will be pulled for good next year. At the time, Microsoft stated: "There will be no exceptions past April 2027." ®