I read on the forum and was able to move my game from iPhone 4 to 5S perfectly.
This is for a complete transfer of old phone to new phone
Steps:
1. Transfer all purchase from old phone to iTunes
2. Backup with encryption old phone to iTunes
3. Restore from backup to new phone
4. Load MW, it will have your game
I didn't transfer purchases in ages, so the process took me about 3 hours from start to finish, game worked perfectly.
Hint, doing normal backup (no encryption did not work the first time for me, but encryption) did)
Last thing I wanted to do was blow away my old phone and be at the mercy of Support, had faction members waiting +1 week to get account.