How can I install "Find my iPhone" on an old iPad 3?

Question

I've recently gotten a new iPad, but my old iPad 3 is still working fine. So I've done a complete wipe on it and I've given it to a friend who has little interest in computing: she just wants to email and get on the internet. My friend will have to undergo surgery next week and will take the iPad 3 with her to the hospital -- she'll be in the hospital for a week or two. Before she went, I wanted to install 'Find my iPhone' on the iPad 3 in case it goes walkabout in the hospital.
However, when I tried to install it, AppStore insisted I upgrade to iOS 8, which I don't think the iPad 3 can pull off. I once upgraded to to iOS 5 or 6 and regretted that real soon -- the iPad 3 just doesn't have the processor speed to handle all that advanced stuff. It's doing fine on iOS 4 and I want to keep it that way. Is there some way to make AppStore install the old 'Find my iPhone'? I still have some backups of the iPad 3 pre-wipe -- could I extract 'Find my iPhone' from there and put it back on the iPad 3 without doing a full restore? Is there some other way we can keep track of the iPad 3 without updating?

Answer 1

If you have iOS 4.3 on it then it's not an iPad 3 (they were initially launched with iOS 5.1 installed on them), it's either a first gen iPad (if it doesn't have cameras), or a 2nd gen : Identify your iPad model - Apple Support.
The Find My iPhone app is used to try and locate other devices from it, it won't help you locate that iPad if it's lost. To be able to potentially locate and track that iPad you need Settings > iCloud > Find My iPad 'on' on it, but iCloud only became available with iOS 5 (so you won't have the setting on iOS 4.3). You will need to update the iPad (you can only update a device to the highest iOS version that it supports i.e. 5.1.1 for the first gen iPad, 8.1.3 for other iPads) if you want to be able to enable it