How can the "when BluetoothLE1.BytesReceived do..." differentiate which bytes are arriving? That is, how to associate/filter to a specific UUID. The examples that I've seen just grab the value that arrives and this works when the app is only looking for one characteristic. My app has several values from multiple services and characteristics. I've tried using an "if then" to match whether the UUID matches the specific service and characteristic uuid values but it's not working
Show your relevant Blocks and your device script.
In your App, you can register for value types, for example register for strings via Service UUID and Characteristic UUID.
You can also prefix values with an identifier.
https://www.professorcad.co.uk/appinventortips#TipsBluetooth