MQTT topic to receive configuration updates

[Stanislav Lvovich]

Could you explain how to subscribe to updates of shadow configuration
using the account device (from an external cloud connected to MQTT) 

I have tried to use the root topic 
But i receive `shadow.desire` updates sent from UI ( /{deviceId}/shadow/update/delta )
Hot to get `shadow.ported` updates ?

[Markus Tacker (he/him)]

You can subscribe to `/{deviceId}/shadow/update/documents`.

[Stanislav Lvovich]

Hi, thank you for your reply

Do you mean {nrfcloud_mqtt_topic_prefix}/{deviceId}/shadow/update/documents` , right?

I have tried to subscribe to root topic {nrfcloud_mqtt_topic_prefix} and did not see any updates from shadow/update/documents

I'm connecting to the MQTT by the common device account client

[Markus Tacker (he/him)]

No. The shadow-documents are per-device, and you can only subscribe to the device-shadow topics from the device you are connecting as. 

This means the account cannot subscribe to AWS IoT shadow topics from other devices.

[Stanislav Lvovich]

So, maybe there is another way to understand a device has updated a config?

For example,
- the customer backend is updating `device.config` (shadow.config), using the nRF REST API method
- the device will update its config when online
- The customer backend wants to know when it happens (to update UI or else)

[Markus Tacker (he/him)]

Right now the only way to know when a regular device has updated its shadow is to poll the REST endpoint `FetchDevice`.