The host application runs on nRF54L15 and uses the nRF91M1 Serial Modem for cellular data over PPP. Modules communicate over zbus and coordinate with SMF state machines. After the network and cloud are up, the main module periodically sends a demo device message and requests a FOTA poll.
See Application behavior for the full startup sequence, cloud synchronization, and Memfault integration, and Architecture for the module design and state machines.
CoAP authentication uses a JWT signed with the installed private key. Only the CA certificate and private key are required at runtime. The device certificate is used for portal onboarding.