I downloaded it, but it's far inferior to
MetalKid's IV Calculator, which also works in the iOS Safari browser.
The app does not take into account the data from the IV Judge, or the Hidden Power checker woman in Fortree (ORAS) / Anistar (XY). Also it doesn't combine the data from multiple levels like you can get by entering multiple rows in MetalKid's calc.
Its Pokédex is quite good but doesn't include the new ORAS move tutors. I have to add that much of the text in the app is badly translated from Japanese, though still understandable.