Is it PC or android version?
If PC try redownloading the game, unpack it somewhere else and try again.
If Android try installing the same version on top of the existing one, if that doesnt help, the. I'm afraid you'll have to either wait for next release or reinstall the game
You can try clearing the cache in case of Android - it might help, but I don't guarantee it (this won't delete your save data so it would be a good idea to try)