If you want to upload a file in the documents app that already exists, you will be notified that this is not possible. However, you will not be asked to replace the file.

You will receive this notification in Sharepoint.

Is it also possible / desirable to add this to the documents app?

* Edited: Translated to English, thanks Google Translate. Please refer to the posting rules and to avoid the translation to miss the payload of the request. Laurens | Workspace 365