After moving the Backup directory location, do I need to move the old backups?

I just added a new volume to a client's vps because the backups were causing them to run out of space and changed the Backup folder to be on the new drive. The system is set to retain the 5 most recent backups. Should I leave the old backups where they are, meaning will the system recognize that is the old location and remove the oldest as it creates the new backups in the new location? Or should I move them over? Or, are they now stranded regardless and I will need to manually delete them as the new ones are created? Thanks. -Michael