[itsme]

Sorry Mike, I don't get the advantage of that change. Does it make sense to change the existing SongID from numerical to a text field and introduce a new synchronization ID which is more or less a copy of the current SongID. At least for my use case of matching setlists, the new synchronization ID would need to get more or less the same features as the existing SongID: visible in title format, configurable manually, used for matching songs with different names and files and so on.
Why not just fine-tune the existing SongID (make it unique, allow usage as sort criteria, improve filtering...) and add a (or maybe several) custom field(s) that can be named by the user and can be flexibly used for any purpose.