Microsoft’s September 2025 Exchange Server Hotfix Updates fix hybrid app issues, with support for SE, 2019, and 2016 versions ...

Microsoft also is advising customers who rely on the on-premises version of Exchange to move to the 2019 version as soon as possible. Microsoft will support Exchange Server until October 14, 2025.

CISA urged users of on-premises Exchange servers to download Microsoft’s April 2025 Exchange Server hotfix updates.

Microsoft removes the August Exchange Server security update after admins complain it disabled their server installations.