Change function "deleteUnexistingFiles" in the CMS installer script "administrator/components/com_admin/script.php" so that folders are only attempted to be deleted if they are empty when updating the CMS.
This PR is incomplete or even wrong as it is, and I don't even think that the files and folder deletion should be changed in CMS version 3, because in opposite to version 4 it might be (I haven't checked that) that the list of files and folders to be deleted contains only a parent folder but not subfolders and files in some case.
Sorry for having wasted your time.
This PR is incomplete or even wrong as it is, and I don't even think that the files and folder deletion should be changed in CMS version 3, because in opposite to version 4 it might be (I haven't checked that) that the list of files and folders to be deleted contains only a parent folder but not subfolders and files in some case.
Let's continue discussion in the issue.