Updates and Versions of Files

I’m using ipfs-desktop and I’m tying to update a file by uploading a modified version of that file to the same directory with the same filename. But this method is rejected. So how can I update a file?

Second, I added a new file to a directory, thus the hash of the directory changes. I’m missing the link in ipfs desktop to the previous version of that directory. Am I missing out something?

Regards,
Martin