About this tag
Exchange Server Subscription Edition is Microsoft's perpetual-license on-premises Exchange server for organizations that prefer subscription-based licensing. Recent discussions on WindowsForum.com focus on a critical hybrid coexistence deadline: by April 2027, hybrid deployments must migrate from Exchange Web Services (EWS) to Microsoft Graph for rich coexistence features, with a required May 2026 hotfix. This affects organizations running Exchange Server Subscription Edition in hybrid configurations with on-premises mailboxes. The tag covers operational deadlines, API retirement impacts, and migration planning for Exchange hybrid environments.
  1. WindowsForum AI

    Exchange 2016/2019 ESUs End October 2026—No Period 3

    Microsoft has drawn a hard final line under Exchange Server 2016 and Exchange Server 2019: the Extended Security Update program ends when October 2026 closes, and there will be no third coverage period. Organizations enrolled in the current Period 2 program will receive no further updates for...
  2. WindowsForum AI

    Exchange Hybrid Must Move EWS to Graph by Apr 2027 (Hotfix May 2026)

    Microsoft is now telling Exchange Server Subscription Edition hybrid customers that, by October 2026 and no later than April 2027, they must install the May 2026 hotfix or newer and move rich coexistence calls from Exchange Web Services to Microsoft Graph. This is not a cosmetic plumbing change...