Office Online Server end of life: 5 options for SharePoint Server SE (2026)

Office Online Server (OOS) reaches end of support on 31 December 2026. If your organisation runs SharePoint Server Subscription Edition (SE), you need to decide what replaces browser viewing of Word, Excel and PowerPoint files. This guide compares the five realistic options, with the facts that matter for the decision and links to the primary sources.

The short answer

• Documents may leave your network and you want co-authoring: migrate to SharePoint Online and Microsoft 365. This is the path Microsoft recommends, and the biggest project.
• Documents must stay on-premises and you need browser editing now: evaluate an open-source office suite such as Collabora Online or ONLYOFFICE Docs, which connect to SharePoint over WOPI.
• Documents must stay on-premises and reading in the browser is what your users need: a dedicated Office Online Server replacement, such as Office Render Engine, uses the same WOPI binding on Windows Server.
• Your users all have desktop Office and you can live without browser viewing: remove the binding and rely on the desktop apps.
• Keeping OOS unsupported buys time, but no security fixes.

What changes on 31 December 2026

Microsoft lists the retirement on its Office Online Server lifecycle page. The official announcement states that after this date OOS "will no longer receive security updates, bug fixes, or technical support", and that Microsoft's recommended path is Microsoft 365. There is no on-premises successor.

The SharePoint team adds two points that shape every option below:

• Microsoft will not actively block OOS in SharePoint Server after the retirement date, but it will not be supported in any configuration, including with SharePoint Server SE.
• Without OOS, users lose viewing, editing and collaboration on Office documents in the browser, and thumbnails in libraries and search results are no longer supported. Office desktop apps keep working.

SharePoint Server SE itself is not going away. It follows the Modern Lifecycle Policy, and Microsoft states it will not reach end of support before 31 December 2035. Public updates ship monthly and each one is supported for one year. So the question is not whether to keep SharePoint SE, but what renders its documents.

Four questions that decide it

1. Must documents stay on-premises? Data sovereignty rules, public sector requirements or customer contracts often answer this before anything else.
2. Do users need to edit in the browser now, or mainly read? Many intranets and document libraries are read far more often than they are edited.
3. How much effort and change can you absorb? A binding switch takes days. A tenant migration takes months.
4. Which servers can you run? Some options need Linux or containers, others run on Windows Server next to your farm.

Option 1: Keep Office Online Server, unsupported

Nothing changes on 1 January 2027: OOS keeps running and SharePoint keeps using it. The catch is that every vulnerability found afterwards stays open, on a server that opens every document your users click. Most security policies do not allow that for long, and audits will ask about it.

Good for: buying a few months while you decide. Not for: a permanent answer.

Option 2: Desktop Office only

You can remove the OOS binding and let users open documents in the desktop apps. Microsoft states that Microsoft 365 Apps for enterprise and Office LTSC 2024 remain supported clients for documents on SharePoint Server SE.

What you lose: viewing in the browser, previews in libraries and search results, and access from machines without Office installed. What you keep: full editing, in the desktop apps.

Good for: small teams where everyone has desktop Office. Not for: kiosk and shared machines, external or occasional users, or intranets where people mostly read.

Option 3: Migrate to SharePoint Online and Microsoft 365

This is Microsoft's recommended path. You get Office for the web with co-authoring, and Microsoft runs the service.

Two points to plan for. First, Office for the web cannot be pointed at an on-premises SharePoint SE farm: its WOPI integration is reserved for Cloud Storage Partner Program members, not customers. So this option means moving the content. Second, the SharePoint Migration Tool lists SharePoint Server 2010 to 2019 as sources, not Subscription Edition, so confirm your migration tooling early.

Good for: organisations already moving to Microsoft 365. Not for: content that must stay on-premises.

Option 4: An open-source office suite (Collabora Online, ONLYOFFICE Docs)

Both products run on your own servers, typically on Linux or in containers, and both offer viewing and editing in the browser.

• Collabora Online connects to SharePoint with a standard WOPI binding, the same mechanism OOS uses (integration page). The vendor states that its documentation covers SharePoint Subscription Edition since June 2026. Business subscriptions start at €3 per user per month for up to 99 users, with Enterprise pricing on request (subscriptions).
• ONLYOFFICE Docs offers two routes (help centre): a WOPI binding, documented for SharePoint Subscription Edition, and a farm connector with more features that is officially listed for SharePoint 2019. The Enterprise edition is licensed by simultaneous connections, priced on request (editions).

Neither is certified by Microsoft; support comes from the vendor. Rendering is done by each suite's own engine, so test your own documents.

Good for: teams that need browser editing on-premises and can run Linux servers. Not for: teams that want to change nothing beyond the binding.

Option 5: A dedicated Office Online Server replacement

A dedicated replacement takes the place of OOS behind the same WOPI binding, so SharePoint, your users and your processes stay as they are. Office Render Engine is one: it runs on Windows Server inside your network with no connection to the internet, shows Word, Excel, PowerPoint and PDF in the browser, and brings back hover previews in SharePoint search. It is view-only today; editing in the browser is in development without a release date. Pricing is €0.50 per SharePoint user per month, billed annually. Other vendors, such as Thinkfree, also market self-hosted OOS replacements; check their SharePoint SE support directly with them.

Good for: on-premises farms where most document access is reading. Not for: teams that need browser editing today.

The options side by side

Option	Browser viewing	Browser editing	Data stays on-premises	Integration effort	Cost model
Keep OOS, unsupported	Yes	Yes	Yes	None now, risk grows	Existing licences, no support
Desktop Office only	No	In desktop apps	Yes	Low: remove the binding	Microsoft 365 Apps or Office LTSC 2024
SharePoint Online / Microsoft 365	Yes	Yes, with co-authoring	No	High: content migration	Microsoft 365 per user
Collabora Online	Yes	Yes	Yes	Low to medium: WOPI binding, Linux server	Per user subscription
ONLYOFFICE Docs	Yes	Yes	Yes	Medium: WOPI binding or farm connector	Per simultaneous connection
Office Render Engine	Yes	Not yet	Yes	Low: same WOPI binding, Windows Server	€0.50 per user per month

Sources linked in the text. Vendor details as published by each vendor in October 2026.

How to decide in one afternoon

1. Run Get-SPWOPIBinding on each farm and list the file types and zones bound to OOS.
2. Ask the data protection and security teams whether documents may leave your network.
3. Look at usage: how often are documents edited in the browser compared with viewed?
4. Shortlist at most two options and test them on a test farm or extra zone with a sample of your real documents.
5. Check the details that differ between products: your authentication setup, search previews and the file types you rely on. This applies to every third-party option, ours included.
6. Plan the switch before December, with a rollback path to OOS while it is still supported.

Frequently asked questions

Will Office Online Server stop working on 1 January 2027? No. Microsoft will not block it, but it receives no further updates, including security updates, and is unsupported in every configuration.

Can I use Office for the web with my on-premises SharePoint SE farm? No. Microsoft does not offer that for customers; browser editing in Microsoft 365 requires the content to be in SharePoint Online.

Do previews in SharePoint search come back with a replacement? They depend on the WOPI client. Office Render Engine shows them; for any product, test this in your pilot.

What do I need to switch the binding? Farm administrator rights, a DNS name and a trusted HTTPS certificate for the new server, and a test with an ordinary user account. Our end-of-life guide walks through the steps.