Android: download and install the app directly — it keeps itself updated from inside. iPhone: we're not on the App Store yet, so use PDR Knock in Safari (instructions below).
Not on the Play Store yet, so you install the APK file yourself. Once installed, PDR Knock checks for a new version every time you open it and offers the update in-app.
iOS can't install app files from the web like Android can, so there's nothing to download here yet. Until the App Store listing is live, run PDR Knock from Safari — it works the same in the field.
Open PDR Knock in SafariQuestions? Request a demo or ask your account manager for a login first.