It's not an App like some other cruise liners have, sitting in Google Play or Apple Store. It's actually a website redirect, which provides things like the Daily Programme and your onboard account. So if you look it on a cellphone it looks a bit App like (but it's still website hosted) - see below - and you can also access it via a laptop or a tablet. Personally I find it useful and haven't had reliability issues, once past the initial login process. Others manage perfectly well without it.