Merge pull request #54 from eshashah-msft/patch-1

Update readme.md

examples/Azure_IoT_Adu_ESP32/readme.md

@@ -52,7 +52,7 @@ _The following was run on Windows 11, with Arduino IDE 2.1.0 and ESP32 board lib
 
 - Have an [Azure account](https://azure.microsoft.com/) created.
 - Have an [Azure IoT Hub](https://docs.microsoft.com/azure/iot-hub/iot-hub-create-through-portal) created.
-  > Important: To use Azure Device Update you must have an Azure IoT Hub with [scale unit](https://learn.microsoft.com/azure/iot-hub/iot-hub-scaling) S1, S2, S3 or a free/standard hub. This sample will not work with a Azure IoT Hub 'Basic' scale unit. 
+  > Important: To use Azure Device Update you must have an Azure IoT Hub with [scale unit](https://learn.microsoft.com/azure/iot-hub/iot-hub-scaling) S1, S2, S3. This sample will not work with a Azure IoT Hub 'Basic' scale unit or free tier. 
 - Have an [Azure Device Update](https://docs.microsoft.com/azure/iot-hub-device-update/create-device-update-account?tabs=portal) instance created and linked to your Azure IoT Hub.
 - Have a logical device created in your Azure IoT Hub: using authentication type "Symmetric Key" or "X.509 self-signed".   
   - **Symmetric Key**: follow [this guidance](https://docs.microsoft.com/azure/iot-hub/iot-hub-create-through-portal#register-a-new-device-in-the-iot-hub) to create a device.In this case, the device keys are used to automatically generate a SAS token for authentication.