Exchange Online to block legacy ActiveSync clients in 2026
19 décembre 2025 à 11:16
Microsoft announced that Exchange Online will block devices using Exchange ActiveSync protocol versions earlier than 16.1 from connecting to its services starting March 1, 2026. This change affects organizations using mobile devices with native email applications to access Exchange Online mailboxes and aims to strengthen security and reliability across the platform. Clients using basic authentication for an affected protocol will be unable to connect to Exchange Online and will receive an HTTP 401 error stating "bad username or password."