Q: Downloading a previous version of ibooks

Had you previously downloaded the app on the account i.e. is it in the account's purchase history ? If not see if the app is still in your country's App Store, and if it is try downloading it - see if this link works : https://itunes.apple.com/app/ibooks/id364709193?mt=8

If you can get it into you account's purchase history, go to the Purchased tab in App Store on your phone and select the app, and you might be able to download an older compatible version of it : Install an app on an earlier version of iOS or OS X - Apple Support

By 'doesn't work' do you mean that it doesn't download and doesn't get added to your account' purchase history ?

As for using a newer device

You need to use a computer's iTunes, not an iOS device, that is the only way to potentially get it into your account's purchase history,