Hi,
I tried the update version for My Passport Ultra, setting it up for Dropbox backup.
I ran the backup. After it was finished i examined the folders comparing the source against the destination.
There where several files that didn’t get backed up. I tracked one down. For instance the .NET assembly file named
Xamarin.Android.Support.v7.RecyclerView.dll
The version of WD Backup is 1.7.6289.16232 which I wanted to try after you fixed the issue “Cannot sign into Dropbox via WD Backup”