You can save your game by connecting it to a Game Center account, regardless of your iOS version. Game Center supports only one save game per account and trying to use multiple games with one account may result in the loss of your save(s).
1. Go to your device's Settings > Game Center
2. Log in with your Apple ID
3. Launch Our World
4. Open Player Settings in the upper left corner of the map
5. Tap “Connect” and your game status changes to “Game Saved”