There's no way to overwrite files if they exist

[FdelMazo]

Currently, the action only uploads files in the mode "add", which tries to append stuff to a file if it already exists. It would be really good if it also had support for the "rename" and "overwrite" modes

[aTable]

This is intentional so that the prototype didn't cause data loss. As I don't actually use dropbox myself, I have no intention to implement this however, it looks like people have forked this and extended further.

This fork looks promising