How to recover Old BackUp?
iTunes usually just updates the previous backup as part of its incremental backup process. But you can look in the iTunes Preferences ->  Devices tab to see all of the backups iTunes sees to make sure:

https://support.apple.com/en-us/HT204215

To make extra sure that there's not a partial or broken backup that iTunes isn't seeing, you can also go look in the folder for the backups. Here's an article I wrote with instructions for getting to the iTunes backups folder on different OSes:

https://deciphertools.com/blog/where-are-iphone-backups/