For those interested in an online collaborative Office suite à la Google Docs, you might consider OnlyOffice. OnlyOffice is offered as a hosted service, Enterprise Edition and free Community Edition. There is also a related Desktop application.
The range of features is extensive and pretty impressive. The interface is clean and well done. The overall focus is Microsoft-centric although the server will accept LibreOffice docs, PDF and standard garden-variety graphics (not necessarily editable, however).
The OnlyOffice Server includes three parts: A Community Server, Document Server and Mail Server. You may choose not to run the Mail Server but the other two are pretty much mandatory.
From their forum notes:
“Free open source office suite with business productivity tools: document and project management, CRM, mail aggregator.”
"The new version of Document Server 4.0 includes such features as:
commenting and integrated chat;
fast real-time co-editing like in Google Docs;
reviewing and tracking changes;
formula language and regional settings;
adding, removing and modifying the available styles.
Also an update to Community Server to version 8.9 with the following functionality was released:
mail and calendar integration
The server can be deployed on Windows or Linux but Docker on Linux seems to be the recommended approach. VMs are also supported.
The server can connect to Seafile via WebDAV from within the Community Server so that files can be accessed for editing (I have to move/copy them from Seafile first) and then returned to Seafile for storage.
for more info.