When a new update releases, how do I download it without losing my saves? Do I have to uninstall the old version?
On android there is no way to "save" your saves. But in the new release there is an option to go straight to new content. So we suggest to do a full playthrough on your current version and then just to check what's new in the next release.
On windows and mac saves are stored on computer and will be transferred automatically between versions.