Occasionaly I try to clean up my iOS-device by deleting apps that I barely use, which includes games. I've played a lot of games on my iOS-device, some will release new content after a few months, some won't.
What will happen to my progression if I delete an app and the developer decides to release new content that I'd like to play. Will I have to restart from scratch, is my progression saved or is this up to the developer? Are there any ways to back-up progression before deleting an app?