Hello!! To update the game you just simply download the game again when a new update releases, this will create a new file for the game but all of your progress (eg: saves, gallery, etc) is saved via your local files on your device so no need to panic if you accidentally delete the game. You can delete the old version if you wish to save storage if you want as all of your progress will transfer to the new one.
The update isn't currently out just yet but will be probably later today, if you have any more questions about the update feel free to ask!!