iTunes: How to find backup corresponding to a particular version of iOS? I have an iPhone 8 Plus, which I upgraded to iOS 12.3.2. iOS 12.3.2 was a special bug fix release which is available only for iPhone 8 Plus models.

I want to downgrade it to iOS 12.3.1, but I think I already did an iTunes backup for iOS 12.3.2.

How can I find a backup in iTunes which can be restored to iOS 12.3.1?
If you have an old 12.3.1 backup of your iPhone, you can restore your iphone from that backup.

Then you have to delete (or drag outside the folder) your 12.3.2 backup so that iTunes restore your device from the new "latest one".

from Apple support :

Find iOS backups on your Mac

Find a list of your backups:


Click Search icon in the menu bar.
Type or copy and paste this: ~/Library/Application Support/MobileSync/Backup/
Press Return.


OR

Locate a specific backup:


Open iTunes. Click iTunes in the menu bar, then choose Preferences.
Click Devices.
Control-click the backup that you want, then choose Show in Finder.