We want to let our Exchange Server customers know that the Office Online Server (OOS) team has announced product retirement on December 31, 2026: Announcing the retirement for Office Online Server.
Office Online Server is an optional component that can be integrated with Exchange Server on-premises and it provides the ability to work with supported types of file attachments within Outlook on the web without having to download them, first.
The following actions in Exchange Server make use of Office Online Server:
- Previewing Office file types in OWA
- Live edit capabilities in OWA
Microsoft will not actively block usage of OOS in Exchange Server after its retirement. However, it's no longer maintained, and no further (security) updates will be provided.
After Office Online Server retirement, on-premises users will need to first download the attachments to view / work with them. Exchange Online users will continue to be able to work with attachments using Outlook on the web since OOS is not being used in the cloud.
For more information, please see Announcing the retirement for Office Online Server.
The Exchange Team
