Request for Information Regarding Microsoft 365 Apps Server

“Microsoft 365 Apps Server” is not the documented product name; for an on-premises server that provides browser-based Word, Excel, PowerPoint, and OneNote integration with SharePoint Server, the supported product is Office Online Server (OOS).^1^

Product distinction

If the requirement is to let SharePoint users view or edit Office documents in a browser, deploy Office Online Server, not Microsoft 365 Apps on the SharePoint server.

SharePoint Server Subscription Edition compatibility

Office Online Server is explicitly listed as compatible with SharePoint Server Subscription Edition.^2^ SharePoint Subscription Edition can also use a linked OOS farm to render document thumbnails.^3^

Use separate servers or VMs:

• Do not install Office Online Server on a SharePoint, Exchange, SQL Server, or domain-controller machine.
• Do not install desktop Office on an OOS server.
• Microsoft also does not support installing Microsoft Office and SharePoint Server Subscription Edition on the same computer.^4^

After creating the OOS farm, connect SharePoint from an elevated SharePoint Management Shell. For a production HTTPS deployment, the core binding is:

New-SPWOPIBinding -ServerName "oos.contoso.com"
Get-SPWOPIZone

# Use this only if the required zone differs:
Set-SPWOPIZone -Zone "internal-https"

Microsoft’s configuration article documents the WOPI binding and zone selection. Production deployments should use HTTPS; HTTP is intended primarily for testing.^5^

Licensing

For OOS browser editing, Microsoft states that on-premises OOS customers receive an Office-for-the-web editing right when they have purchased an eligible desktop suite license, such as:

• Office Professional Plus
• Office Standard
• Microsoft 365 Apps for enterprise

Viewing and editing rights are different, so confirm the exact users, workloads, and agreement terms against the current Microsoft Product Terms or with the organization’s Microsoft licensing partner.^6^

This should not be confused with Microsoft 365 Apps licensing modes. Microsoft 365 Apps supports user-based licensing, shared-computer activation, and—under qualifying agreements—device-based licensing.^7^

Supported infrastructure for Office Online Server

OOS supports the 64-bit editions of:

• Windows Server 2012 R2
• Windows Server 2016, with the required OOS build
• Windows Server 2019, with the July 2021 patch or later
• Windows Server 2022, with the November 2021 patch or later

For Windows Server 2016–2022, OOS requires Server with Desktop Experience. Windows Server 2025 is not listed as supported in the current OOS requirements, so do not assume compatibility.^8^

Additional requirements and practices include:

• Domain membership for all OOS farm servers.
• Dedicated physical machines or VMs.
• HTTPS and a certificate for production.
• A load balancer for multi-server farms.
• Ports 443, 80, and—for private multi-server traffic—809 as applicable.
• All farm nodes in one data center.
• Same Active Directory forest as users and applicable data sources when using certain Excel external-data scenarios.

Installation media

Office Online Server is the Office server product for which an ISO is available. Current volume-license downloads are accessed from:

1. Microsoft 365 admin center
2. Billing → Your products → Volume licensing
3. Products and services → View downloads and keys
4. Select Office Online Server and download the ISO.

The account needs the VL Administrator or Product Download Manager role for the corresponding License ID, and downloading media does not itself establish licensing entitlement.^9^

For comparison, Microsoft 365 Apps does not use an OOS-style server ISO. It is downloaded and deployed using the Office Deployment Tool and Office CDN.^10^

Lifecycle and maintenance

Office Online Server uses a build-based servicing model: Microsoft supports the current build with security and critical updates until the next build is released. Older builds continue to function, but Microsoft may require an upgrade to the latest build before providing a hotfix.^11^

Therefore:

• Patch every OOS node consistently.
• Keep the farm on the latest supported OOS build.
• Test updates before production rollout.
• Treat the OOS lifecycle separately from Microsoft 365 Apps, which follows the Modern Lifecycle Policy and requires customers to remain current.^12^

References

1. Office Online Server overview
2. Office Online Server
3. New and improved features in SharePoint Server Subscription Edition
4. Software requirements for SharePoint Servers for SharePoint Server Subscription Edition
5. Configure Office Online Server for SharePoint Server
6. Office for the web service description
7. Overview of licensing and activation in Microsoft 365 Apps
8. Plan Office Online Server
9. Download volume licensing products
10. Overview of the Office Deployment Tool
11. Office Online Server release schedule
12. Lifecycle FAQ - Office, Office 365, and Microsoft 365