Add to Home Screen
Isshio runs in the browser. From the home screen it starts like an app, in its own window and offline too.
How it works
iPhone: open isshio.com in Safari. Tap the three dots ··· at the bottom right, then “Share”. In older iOS versions “Share” sits directly in the bar at the bottom.
Show more actions if needed, then tap “Add to Home Screen” and “Add”.
Android: the easiest way is Google Play: search for Isshio there, or in the settings under “Add to Home Screen” tap “Install from Google Play”. Without the store: open isshio.com in Chrome, tap the three dots ⋮ (menu) and choose the entry to install, for example “Install app” or “Add to Home screen”.
From now on, start Isshio from the new icon.
Good to know: On iPhone, the app on the home screen has its own storage. Bring the groups you had in Safari over with “Back up codes” and “Restore codes”. The Android app from Google Play has its own storage too.