If you mean the “all changes saved” message at the bottom of the editors page, it indicates that the changes in the document have been successfully sent to the database, allowing a new version of the file to be created in the OO Docs cache.

To create a new version of the file in your storage, a callback handler must be implemented on your end. There are few Document Save Examples available here

"callbackUrl": "https://xxxxx/"

Please describe how you save the file.