Restore important app. data from iOS 10 after an upgrade to iOS 11 Following situation. I am using the "iSafeBox" Password Safe on my iPhone 6s where I keep all of my account and password details. After upgrading to ios11 however, I found that the app is not compatible and that the developer will not continue development. To make things worse, I also cannot go back to iOS 10 as it is not signed anymore...

I have an old iPhone 6 running iOS 10.3 and was hoping I could restore that one with the backup of the 6S, but iTunes tells me that the version is too old and cannot be restored with the iOS 11 backup.

When checking the backup of the iPhone 6S running iOS 11, I found that the unsupported app was still there and got transferred over into my itunes library. I am now wondering if there is any way I can extract that specific app + data, and load it onto my iPhone 6 running iOS 10.3, then continue using it there?

I am open to jailbreak and all sorts of shady stuff as long as I get back access to my passwords T_T

Thank you!
That’s how I solved it:

Requirements


iPhone / iPad with iOS 11 running the password app which is not supported anymore
spare iPhone / iPad running iOS 10 with same password app freshly installed and no data inside


Procedure


download the latest free trial version of the iPhone Explorer
connect the iOS 11 device
go to Apps
select the password app
click MOUNT APP to display the appdata folder in a virtual drive with limited read / write access (Note: the trial version of iPhone explorer offers only 150MB of data to be written)
copy all files and folders to your local hard drive, make sure the folder structure is the same
connect the iOS 10 device
go to apps
select the empty password app
click MOUNT APP and copy over the iOS 11 appdata from your hard drive to the iOS 10 device
disconnect the iOS 10 device
open the password app and enter your master pin 
you should now see your passwords listed as usual


Hope that helps!