I maintain the github repository for ivy, but not the mobile apps. The App Store (iOS) version was taken down because of some internal Google policies that made it too awkward to maintain; the Play Store (Android) version is still available last I checked but is very (very!) old. In any case Google owns or at least has owned both those apps. It would be a good thing to deprecate those either officially or unofficially and issue new versions of the apps using current ivy, which is much more robust, performant, and rich. That could be done by just doing it under some other name such as "Ivy high-precision calculator". I do have verbal permission from Google to do this, but I don't have the skill set—I have zero experience in mobile deployment.
It would also be nice to make the app UI a little better, but that is a separate issue.
-rob