My operation is perhaps strange:
- I record my new ebooks (or those reworked) in a directory that is still empty because I then moved to another which groups them all.
So there can not be any confusion between a new and old version of the same ebook (grant me to know the difference between copying and moving ...

).
In addition, Calibre is configured to back up only the files extension "epub" only, so the converted versions.
In French, I would say "j'en perds mon latin"
mtfbwy