[Geoff Bacon]

You could create a collection called "Not Wanted" or "Discards"; put your old song versions in this collection

When creating set lists, set the filter to ignore this collection.

Alternatively, you could add all your songs to a "Current" collection (very quick to do) and move old duplicates to a discard collection. You then include the "Current" collection in a filter. When a song is superseded (but not overwritten), you move the old version from "Current" to "Discards". One disadvantage of this method is that you need to remember to specify "Current" each time you import a new song.

This means that your old setlists will remain valid ii.e. they show the order of songs and still work. However, should you resurrect the setlist, you need to remember to replace any songs with their updated versions.

You still need to work through the Songs tab looking for very similar sounded names to decide what goes in your Discards collection.
However, after you have done this big exercise once, you should only need to move superseded songs into the Discard collection when you import a new version

Hope this helps
Geoff