In December 2019, we released our Connectivity Settings Fallback Feature, 

On 4G networks, a device is unable to receive an SMS unless it is already connected to the network.

This makes changing parameters, setting APNs and other functions difficult to do remotely, as if a device cannot connect settings cannot be applied via OEM. 

If a device in the field has its settings altered to the wrong APN for example, it will stop connecting and is unable to be recovered without physically retrieving the device. 

For this reason we have developed this new feature which operates as follows:

When a device connects in successfully, it stores the current (i.e. proven to be working) admin parameters in memory.

Then, if it is unable to connect for over 3 days, and there has been a parameter change it will do the following.

1. Revert to the ‘last known working’ set of admin parameters and attempts a connection
2. If a device is not able to successfully register on the network for 3 days, it will attempt an upload with a 10 minute registration timeout (i.e. leave the modem on for 10 minutes continuously). This is a fail safe to allow a device to reconnect if something has gone wrong (i.e. misconfigured settings, timeouts). 
3. The device will use this set of parameters for 8 hours, giving the device a chance to get online and download an updated set of admin parameters

After 8 hours the device will revert back to the current admin parameters. And the 3 day cycle begins again.