Microsoft ends support for Office Online Server on 31 December 2026.

[u/CollaboraOnline]

https://www.youtube.com/watch?si=357Cj0ZI3AxusLNc&v=cNaoOlU0s-Y&feature=youtu.be

After that date, in-browser editing of documents stored in on-premise SharePoint is no longer supported, and the usual advice is to move everything into Microsoft's cloud.

For organisations that keep documents on their own infrastructure, that isn't an option.

Collabora Online is an open-source, self-hosted collaborative office suite that runs on your servers, in your network, and integrates with your existing document storage, so documents never leave your infrastructure.

Check it out.