If you have used Excel Web App (part of Office Web Apps), you are familiar with the fact that there is no “Save” button. The changes you make are immediately saved back to SharePoint and you even have multiple people editing the spreadsheet at the same time with Co-authoring. I had always wondered what happened when it comes to versioning so today I decided to dig a little deeper to find out what happens. We’ll start with editing an Excel document in the browser with versioning enabled. Whenever you change the value of a cell, the results are immediately saved back to SharePoint. However, opening a second browser to look at the versioning shows that we are still on the same version.
The changes have been saved to SharePoint, but no version has been created. Effectively, you can think of this as the same thing as calling .SystemUpdate() for you programmers out there. However, what I have found is if you wait long enough (a couple of minutes), eventually it will go and commit a new version. Otherwise, it will commit a new version when you
A new version will also be created if you close the document (either close out of the file menu or using the breadcrumbs). Where it gets really interesting is when you have multiple editors. You’ll see the same behavior as before, where a new version will be saved a few minutes after the first change. However, if multiple changes have occurred, it will write the last author’s name into the version.
However, ultimately whomever closes their browser session last (or times out last apparently) is the final author of the version. In this case, Anna closes the document first, then I closed it. It then goes back and updates the author and modified date on version 4.
In summary, Excel Web App will create a new version automatically for you if one hasn’t been created whenever you close the editor or after a period of time has elapsed after the first change. Whomever makes changes last will end being the ultimate author of that version. Btw, I have never seen it create a second version of a document when you leave it open for a long period of time. It appears that it will only create one version for a given Co-authoring editing session. Hopefully, this help you understand how versioning with Excel Web App works better. These examples were demonstrated using my Office 365 E3 account.