Word and Excel co authoring in SharePoint 2016

Question

There is a lot of confusion on this topic so I just want to confirm if following is true:

Word = Supports co-authoring via both desktop application and Office Online Server/Office Web App Server

Powerpoint = Supports co-authoring via both desktop application and Office Online Server/Office Web App Server

Excel = Only support co-authoring via Office Online Server/Office Web App Server

Answer 1

SharePoint 2016 on-premise only supports co-authoring with Word and PowerPoint. Co-authoring with Excel desktop or even web-based client (through Office Web Apps Server) is not supported.

Answer 2

Please refer to Feature availability across Office Online plans for a comparison list. All mentioned apps support real time co-authoring via browser and desktop app (Word, Excel, PowerPoint).

More information especially about Excel can be found in Collaborate on Excel workbooks at the same time with co-authoring