Transfer the War Robots progress from Android to iOS

I agree with this question and have an unfortunate answer.

The saddest part of the iOS line is that iTunes does not back up CoreData / Application generated data (save games, favorites, you know, locally saved data). The only way this is feasible is if the application supported saving progress back to the server, and loading it back to the device next time you play. And, clearly, Angry Birds doesn't.

This is an opportunity to contact the developers about Angry Birds and ask them to implement a server-side store of your progress, in ADDITION to the local data.

[edit]
This answer is 50% wrong. A server side store would be great, and iTunes doesn't back up Application generated data, but you CAN pull saved files out with some finagling.

As long as you have a wifi / internet connection, most games should perform syncing with the 'cloud'.

Otherwise, you would need to access where the files are located, usually by some service like: iExplorer and PhoneDisk. If you cannot write to where the game files are stored, then yes, you will need to jailbreak the phone to gain write privileges.