Limiting the shadow document size
The nRF9160 DK has a size limit of 2303 bytes for receiving TLS packages.
See the following contents of the mfw_nrf9160_1.2.0_release_notes.txt
file in nRF9160 modem firmware binaries (v1.2.0) for reference.
The nRF Asset Tracker sets up an IoT rule, which only publishes the cfg
section of the shadow document to a separate topic $aws/things/<thing name>/shadow/get/accepted/desired/cfg
when devices receive their state after publishing an empty message to $aws/things/<thing name>/shadow/get.
The published object can be empty as shown, if the device has no shadow or if the configuration is not set:
{}
Otherwise, the message contains a top-level key cfg
and the desired device configuration as shown below:
{
"cfg": {
"loct": 60,
"act": false,
"actwt": 60,
"mvres": 60,
"mvt": 3600,
"accath": 10.5,
"accith": 5.2,
"accito": 1.7
}
}