Choose between notifications or indications

I tried to look in the documentation and in the code itself for the answer to the question I ask in the title: is it possible to choose whether to subscribe to a characteristic by notification or indication?

(I am in charge of the BLE device firmware, so my knowledge of mobile development is limited. I say this to apologize in advance in case the question is dumb, simple or obvious 😅).

The thing is, I don't know if you can choose whether subscribing to a characteristic via the "subscribeToCharacteristic" method makes use of notifications or indications (i.e. if it will acknowledge or not when receiving data).

I have seen this in the PhilipsHue/flutter_reactive_ble/packages/reactive_ble_mobile/android/src/main/kotlin/com/signify/hue/flutterreactiveble/ble/ReactiveBleClient.kt file:

    private fun setupNotificationOrIndication(
        deviceConnection: EstablishConnectionResult,
        characteristicId: UUID,
        characteristicInstanceId: Int
    ): Observable<Observable<ByteArray>> =
        when (deviceConnection) {
            is EstablishedConnection -> {
                if (rxBleClient.getBleDevice(deviceConnection.deviceId).bluetoothDevice.bondState == BOND_BONDING) {
                    Observable.error(Exception("Bonding is in progress wait for bonding to be finished before executing more operations on the device"))
                } else {
                    deviceConnection.rxConnection.resolveCharacteristic(
                            characteristicId, characteristicInstanceId
                    ).flatMapObservable { characteristic ->
                        val mode = if (characteristic.descriptors.isEmpty()) {
                            NotificationSetupMode.COMPAT
                        } else {
                            NotificationSetupMode.DEFAULT
                        }

                        if ((characteristic.properties and BluetoothGattCharacteristic.PROPERTY_NOTIFY) > 0) {
                            deviceConnection.rxConnection.setupNotification(
                                characteristic,
                                mode
                            )
                        } else {
                            deviceConnection.rxConnection.setupIndication(characteristic, mode)
                        }
                    }
                }
            }
            is EstablishConnectionFailure -> {
                Observable.just(Observable.empty())
            }
        }

In the iOS implementation I haven't even dared to go in to check it out...

I am supposed to assume that if a characteristic has notification permission enabled it is subscribed by notification and only if notification permission is not enabled then it is subscribed by indication? Which would mean that I can't have both permissions enabled. (My Kotlin knowledge is 0...)

Thanks in advance and apologies if the question is dumb...🙇‍♂️

PhilipsHue / flutter_reactive_ble

Choose between notifications or indications #823