Does Windows still keeps old versions of files after each update

Question

Does Windows still keeps old versions of files after each update or remove all old redundant files?

Answer 1

When Windows Update replaces a file, the previous version is not saved in the Recycle Bin, so no redundant files.

When one installs a new Windows version, or if you do an In-place Upgrade, the old Windows files go into the folder Windows.old. However, most of them are deleted after 28 days.