Comment by billfor

At least with the older devices, all the app does is a upnp broadcast to find the wemos, and then issue SOAP requests to turn them on/off. The app will work without an internet connection - you can verify this by disabling your internet and checking. If you need automation or firmware updates, or possibly with some of their newer devices, then you need the internet connection. So just keep the app around (back it up or download from f-droid if on android).